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authorDimitry Andric <dim@FreeBSD.org>2017-01-02 19:19:15 +0000
committerDimitry Andric <dim@FreeBSD.org>2017-01-02 19:19:15 +0000
commitd93e1dfac8711cfed1a9d9cd1876a788b83945cd (patch)
tree5896fa6c02a262a6148b215487e545d937de58b7 /ELF/LinkerScript.cpp
parent8d43286d630f9224de07809ea253e83ebb9cdee6 (diff)
downloadsrc-d93e1dfac8711cfed1a9d9cd1876a788b83945cd.tar.gz
src-d93e1dfac8711cfed1a9d9cd1876a788b83945cd.zip
Vendor import of lld trunk r290819:vendor/lld/lld-trunk-r290819
Notes
Notes: svn path=/vendor/lld/dist/; revision=311125 svn path=/vendor/lld/lld-trunk-r290819/; revision=311126; tag=vendor/lld/lld-trunk-r290819
Diffstat (limited to 'ELF/LinkerScript.cpp')
-rw-r--r--ELF/LinkerScript.cpp2060
1 files changed, 1716 insertions, 344 deletions
diff --git a/ELF/LinkerScript.cpp b/ELF/LinkerScript.cpp
index 61abdc185e11..5057b57a4a54 100644
--- a/ELF/LinkerScript.cpp
+++ b/ELF/LinkerScript.cpp
@@ -8,8 +8,6 @@
//===----------------------------------------------------------------------===//
//
// This file contains the parser/evaluator of the linker script.
-// It does not construct an AST but consume linker script directives directly.
-// Results are written to Driver or Config object.
//
//===----------------------------------------------------------------------===//
@@ -17,311 +15,971 @@
#include "Config.h"
#include "Driver.h"
#include "InputSection.h"
+#include "Memory.h"
#include "OutputSections.h"
#include "ScriptParser.h"
#include "Strings.h"
-#include "Symbols.h"
#include "SymbolTable.h"
+#include "Symbols.h"
+#include "SyntheticSections.h"
#include "Target.h"
+#include "Writer.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/Casting.h"
#include "llvm/Support/ELF.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Path.h"
-#include "llvm/Support/StringSaver.h"
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <vector>
using namespace llvm;
using namespace llvm::ELF;
using namespace llvm::object;
+using namespace llvm::support::endian;
using namespace lld;
using namespace lld::elf;
+LinkerScriptBase *elf::ScriptBase;
ScriptConfiguration *elf::ScriptConfig;
-// This is an operator-precedence parser to parse and evaluate
-// a linker script expression. For each linker script arithmetic
-// expression (e.g. ". = . + 0x1000"), a new instance of ExprParser
-// is created and ran.
-namespace {
-class ExprParser : public ScriptParserBase {
-public:
- ExprParser(std::vector<StringRef> &Tokens, uint64_t Dot)
- : ScriptParserBase(Tokens), Dot(Dot) {}
+template <class ELFT> static void addRegular(SymbolAssignment *Cmd) {
+ uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
+ Symbol *Sym = Symtab<ELFT>::X->addRegular(Cmd->Name, Visibility, STT_NOTYPE,
+ 0, 0, STB_GLOBAL, nullptr, nullptr);
+ Cmd->Sym = Sym->body();
- uint64_t run();
+ // If we have no SECTIONS then we don't have '.' and don't call
+ // assignAddresses(). We calculate symbol value immediately in this case.
+ if (!ScriptConfig->HasSections)
+ cast<DefinedRegular<ELFT>>(Cmd->Sym)->Value = Cmd->Expression(0);
+}
-private:
- uint64_t parsePrimary();
- uint64_t parseTernary(uint64_t Cond);
- uint64_t apply(StringRef Op, uint64_t L, uint64_t R);
- uint64_t parseExpr1(uint64_t Lhs, int MinPrec);
- uint64_t parseExpr();
+template <class ELFT> static void addSynthetic(SymbolAssignment *Cmd) {
+ // If we have SECTIONS block then output sections haven't been created yet.
+ const OutputSectionBase *Sec =
+ ScriptConfig->HasSections ? nullptr : Cmd->Expression.Section();
+ Symbol *Sym = Symtab<ELFT>::X->addSynthetic(
+ Cmd->Name, Sec, 0, Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT);
+ Cmd->Sym = Sym->body();
- uint64_t Dot;
-};
+ // If we already know section then we can calculate symbol value immediately.
+ if (Sec)
+ cast<DefinedSynthetic>(Cmd->Sym)->Value = Cmd->Expression(0) - Sec->Addr;
}
-static int precedence(StringRef Op) {
- return StringSwitch<int>(Op)
- .Case("*", 4)
- .Case("/", 4)
- .Case("+", 3)
- .Case("-", 3)
- .Case("<", 2)
- .Case(">", 2)
- .Case(">=", 2)
- .Case("<=", 2)
- .Case("==", 2)
- .Case("!=", 2)
- .Case("&", 1)
- .Default(-1);
+static bool isUnderSysroot(StringRef Path) {
+ if (Config->Sysroot == "")
+ return false;
+ for (; !Path.empty(); Path = sys::path::parent_path(Path))
+ if (sys::fs::equivalent(Config->Sysroot, Path))
+ return true;
+ return false;
}
-static uint64_t evalExpr(std::vector<StringRef> &Tokens, uint64_t Dot) {
- return ExprParser(Tokens, Dot).run();
+template <class ELFT> static void addSymbol(SymbolAssignment *Cmd) {
+ if (Cmd->Expression.IsAbsolute())
+ addRegular<ELFT>(Cmd);
+ else
+ addSynthetic<ELFT>(Cmd);
+}
+// If a symbol was in PROVIDE(), we need to define it only when
+// it is an undefined symbol.
+template <class ELFT> static bool shouldDefine(SymbolAssignment *Cmd) {
+ if (Cmd->Name == ".")
+ return false;
+ if (!Cmd->Provide)
+ return true;
+ SymbolBody *B = Symtab<ELFT>::X->find(Cmd->Name);
+ return B && B->isUndefined();
}
-uint64_t ExprParser::run() {
- uint64_t V = parseExpr();
- if (!atEOF() && !Error)
- setError("stray token: " + peek());
- return V;
+bool SymbolAssignment::classof(const BaseCommand *C) {
+ return C->Kind == AssignmentKind;
}
-// This is a part of the operator-precedence parser to evaluate
-// arithmetic expressions in SECTIONS command. This function evaluates an
-// integer literal, a parenthesized expression, the ALIGN function,
-// or the special variable ".".
-uint64_t ExprParser::parsePrimary() {
- StringRef Tok = next();
- if (Tok == ".")
- return Dot;
- if (Tok == "(") {
- uint64_t V = parseExpr();
- expect(")");
- return V;
- }
- if (Tok == "ALIGN") {
- expect("(");
- uint64_t V = parseExpr();
- expect(")");
- return alignTo(Dot, V);
- }
- uint64_t V = 0;
- if (Tok.getAsInteger(0, V))
- setError("malformed number: " + Tok);
- return V;
+bool OutputSectionCommand::classof(const BaseCommand *C) {
+ return C->Kind == OutputSectionKind;
}
-uint64_t ExprParser::parseTernary(uint64_t Cond) {
- next();
- uint64_t V = parseExpr();
- expect(":");
- uint64_t W = parseExpr();
- return Cond ? V : W;
+bool InputSectionDescription::classof(const BaseCommand *C) {
+ return C->Kind == InputSectionKind;
}
-uint64_t ExprParser::apply(StringRef Op, uint64_t L, uint64_t R) {
- if (Op == "*")
- return L * R;
- if (Op == "/") {
- if (R == 0) {
- error("division by zero");
- return 0;
- }
- return L / R;
+bool AssertCommand::classof(const BaseCommand *C) {
+ return C->Kind == AssertKind;
+}
+
+bool BytesDataCommand::classof(const BaseCommand *C) {
+ return C->Kind == BytesDataKind;
+}
+
+template <class ELFT> LinkerScript<ELFT>::LinkerScript() = default;
+template <class ELFT> LinkerScript<ELFT>::~LinkerScript() = default;
+
+template <class ELFT> static StringRef basename(InputSectionBase<ELFT> *S) {
+ if (S->getFile())
+ return sys::path::filename(S->getFile()->getName());
+ return "";
+}
+
+template <class ELFT>
+bool LinkerScript<ELFT>::shouldKeep(InputSectionBase<ELFT> *S) {
+ for (InputSectionDescription *ID : Opt.KeptSections)
+ if (ID->FilePat.match(basename(S)))
+ for (SectionPattern &P : ID->SectionPatterns)
+ if (P.SectionPat.match(S->Name))
+ return true;
+ return false;
+}
+
+static bool comparePriority(InputSectionData *A, InputSectionData *B) {
+ return getPriority(A->Name) < getPriority(B->Name);
+}
+
+static bool compareName(InputSectionData *A, InputSectionData *B) {
+ return A->Name < B->Name;
+}
+
+static bool compareAlignment(InputSectionData *A, InputSectionData *B) {
+ // ">" is not a mistake. Larger alignments are placed before smaller
+ // alignments in order to reduce the amount of padding necessary.
+ // This is compatible with GNU.
+ return A->Alignment > B->Alignment;
+}
+
+static std::function<bool(InputSectionData *, InputSectionData *)>
+getComparator(SortSectionPolicy K) {
+ switch (K) {
+ case SortSectionPolicy::Alignment:
+ return compareAlignment;
+ case SortSectionPolicy::Name:
+ return compareName;
+ case SortSectionPolicy::Priority:
+ return comparePriority;
+ default:
+ llvm_unreachable("unknown sort policy");
}
- if (Op == "+")
- return L + R;
- if (Op == "-")
- return L - R;
- if (Op == "<")
- return L < R;
- if (Op == ">")
- return L > R;
- if (Op == ">=")
- return L >= R;
- if (Op == "<=")
- return L <= R;
- if (Op == "==")
- return L == R;
- if (Op == "!=")
- return L != R;
- if (Op == "&")
- return L & R;
- llvm_unreachable("invalid operator");
}
-// This is a part of the operator-precedence parser.
-// This function assumes that the remaining token stream starts
-// with an operator.
-uint64_t ExprParser::parseExpr1(uint64_t Lhs, int MinPrec) {
- while (!atEOF()) {
- // Read an operator and an expression.
- StringRef Op1 = peek();
- if (Op1 == "?")
- return parseTernary(Lhs);
- if (precedence(Op1) < MinPrec)
- return Lhs;
- next();
- uint64_t Rhs = parsePrimary();
+template <class ELFT>
+static bool matchConstraints(ArrayRef<InputSectionBase<ELFT> *> Sections,
+ ConstraintKind Kind) {
+ if (Kind == ConstraintKind::NoConstraint)
+ return true;
+ bool IsRW = llvm::any_of(Sections, [=](InputSectionData *Sec2) {
+ auto *Sec = static_cast<InputSectionBase<ELFT> *>(Sec2);
+ return Sec->Flags & SHF_WRITE;
+ });
+ return (IsRW && Kind == ConstraintKind::ReadWrite) ||
+ (!IsRW && Kind == ConstraintKind::ReadOnly);
+}
- // Evaluate the remaining part of the expression first if the
- // next operator has greater precedence than the previous one.
- // For example, if we have read "+" and "3", and if the next
- // operator is "*", then we'll evaluate 3 * ... part first.
- while (!atEOF()) {
- StringRef Op2 = peek();
- if (precedence(Op2) <= precedence(Op1))
- break;
- Rhs = parseExpr1(Rhs, precedence(Op2));
+static void sortSections(InputSectionData **Begin, InputSectionData **End,
+ SortSectionPolicy K) {
+ if (K != SortSectionPolicy::Default && K != SortSectionPolicy::None)
+ std::stable_sort(Begin, End, getComparator(K));
+}
+
+// Compute and remember which sections the InputSectionDescription matches.
+template <class ELFT>
+void LinkerScript<ELFT>::computeInputSections(InputSectionDescription *I) {
+ // Collects all sections that satisfy constraints of I
+ // and attach them to I.
+ for (SectionPattern &Pat : I->SectionPatterns) {
+ size_t SizeBefore = I->Sections.size();
+
+ for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections) {
+ if (!S->Live || S->Assigned)
+ continue;
+
+ StringRef Filename = basename(S);
+ if (!I->FilePat.match(Filename) || Pat.ExcludedFilePat.match(Filename))
+ continue;
+ if (!Pat.SectionPat.match(S->Name))
+ continue;
+ I->Sections.push_back(S);
+ S->Assigned = true;
}
- Lhs = apply(Op1, Lhs, Rhs);
+ // Sort sections as instructed by SORT-family commands and --sort-section
+ // option. Because SORT-family commands can be nested at most two depth
+ // (e.g. SORT_BY_NAME(SORT_BY_ALIGNMENT(.text.*))) and because the command
+ // line option is respected even if a SORT command is given, the exact
+ // behavior we have here is a bit complicated. Here are the rules.
+ //
+ // 1. If two SORT commands are given, --sort-section is ignored.
+ // 2. If one SORT command is given, and if it is not SORT_NONE,
+ // --sort-section is handled as an inner SORT command.
+ // 3. If one SORT command is given, and if it is SORT_NONE, don't sort.
+ // 4. If no SORT command is given, sort according to --sort-section.
+ InputSectionData **Begin = I->Sections.data() + SizeBefore;
+ InputSectionData **End = I->Sections.data() + I->Sections.size();
+ if (Pat.SortOuter != SortSectionPolicy::None) {
+ if (Pat.SortInner == SortSectionPolicy::Default)
+ sortSections(Begin, End, Config->SortSection);
+ else
+ sortSections(Begin, End, Pat.SortInner);
+ sortSections(Begin, End, Pat.SortOuter);
+ }
}
- return Lhs;
}
-// Reads and evaluates an arithmetic expression.
-uint64_t ExprParser::parseExpr() { return parseExpr1(parsePrimary(), 0); }
-
template <class ELFT>
-StringRef LinkerScript<ELFT>::getOutputSection(InputSectionBase<ELFT> *S) {
- for (SectionRule &R : Opt.Sections)
- if (globMatch(R.SectionPattern, S->getSectionName()))
- return R.Dest;
- return "";
+void LinkerScript<ELFT>::discard(ArrayRef<InputSectionBase<ELFT> *> V) {
+ for (InputSectionBase<ELFT> *S : V) {
+ S->Live = false;
+ reportDiscarded(S);
+ }
}
template <class ELFT>
-bool LinkerScript<ELFT>::isDiscarded(InputSectionBase<ELFT> *S) {
- return getOutputSection(S) == "/DISCARD/";
+std::vector<InputSectionBase<ELFT> *>
+LinkerScript<ELFT>::createInputSectionList(OutputSectionCommand &OutCmd) {
+ std::vector<InputSectionBase<ELFT> *> Ret;
+
+ for (const std::unique_ptr<BaseCommand> &Base : OutCmd.Commands) {
+ auto *Cmd = dyn_cast<InputSectionDescription>(Base.get());
+ if (!Cmd)
+ continue;
+ computeInputSections(Cmd);
+ for (InputSectionData *S : Cmd->Sections)
+ Ret.push_back(static_cast<InputSectionBase<ELFT> *>(S));
+ }
+
+ return Ret;
}
template <class ELFT>
-bool LinkerScript<ELFT>::shouldKeep(InputSectionBase<ELFT> *S) {
- for (StringRef Pat : Opt.KeptSections)
- if (globMatch(Pat, S->getSectionName()))
- return true;
- return false;
+static SectionKey<ELFT::Is64Bits> createKey(InputSectionBase<ELFT> *C,
+ StringRef OutsecName) {
+ // When using linker script the merge rules are different.
+ // Unfortunately, linker scripts are name based. This means that expressions
+ // like *(.foo*) can refer to multiple input sections that would normally be
+ // placed in different output sections. We cannot put them in different
+ // output sections or we would produce wrong results for
+ // start = .; *(.foo.*) end = .; *(.bar)
+ // and a mapping of .foo1 and .bar1 to one section and .foo2 and .bar2 to
+ // another. The problem is that there is no way to layout those output
+ // sections such that the .foo sections are the only thing between the
+ // start and end symbols.
+
+ // An extra annoyance is that we cannot simply disable merging of the contents
+ // of SHF_MERGE sections, but our implementation requires one output section
+ // per "kind" (string or not, which size/aligment).
+ // Fortunately, creating symbols in the middle of a merge section is not
+ // supported by bfd or gold, so we can just create multiple section in that
+ // case.
+ typedef typename ELFT::uint uintX_t;
+ uintX_t Flags = C->Flags & (SHF_MERGE | SHF_STRINGS);
+
+ uintX_t Alignment = 0;
+ if (isa<MergeInputSection<ELFT>>(C))
+ Alignment = std::max<uintX_t>(C->Alignment, C->Entsize);
+
+ return SectionKey<ELFT::Is64Bits>{OutsecName, /*Type*/ 0, Flags, Alignment};
}
template <class ELFT>
-void LinkerScript<ELFT>::assignAddresses(
- ArrayRef<OutputSectionBase<ELFT> *> Sections) {
- // Orphan sections are sections present in the input files which
- // are not explicitly placed into the output file by the linker script.
- // We place orphan sections at end of file.
- // Other linkers places them using some heuristics as described in
- // https://sourceware.org/binutils/docs/ld/Orphan-Sections.html#Orphan-Sections.
- for (OutputSectionBase<ELFT> *Sec : Sections) {
- StringRef Name = Sec->getName();
- if (getSectionIndex(Name) == INT_MAX)
- Opt.Commands.push_back({SectionKind, {}, Name});
- }
+void LinkerScript<ELFT>::addSection(OutputSectionFactory<ELFT> &Factory,
+ InputSectionBase<ELFT> *Sec,
+ StringRef Name) {
+ OutputSectionBase *OutSec;
+ bool IsNew;
+ std::tie(OutSec, IsNew) = Factory.create(createKey(Sec, Name), Sec);
+ if (IsNew)
+ OutputSections->push_back(OutSec);
+ OutSec->addSection(Sec);
+}
- // Assign addresses as instructed by linker script SECTIONS sub-commands.
- Dot = Out<ELFT>::ElfHeader->getSize() + Out<ELFT>::ProgramHeaders->getSize();
- uintX_t MinVA = std::numeric_limits<uintX_t>::max();
- uintX_t ThreadBssOffset = 0;
+template <class ELFT>
+void LinkerScript<ELFT>::processCommands(OutputSectionFactory<ELFT> &Factory) {
+ for (unsigned I = 0; I < Opt.Commands.size(); ++I) {
+ auto Iter = Opt.Commands.begin() + I;
+ const std::unique_ptr<BaseCommand> &Base1 = *Iter;
- for (SectionsCommand &Cmd : Opt.Commands) {
- if (Cmd.Kind == AssignmentKind) {
- uint64_t Val = evalExpr(Cmd.Expr, Dot);
+ // Handle symbol assignments outside of any output section.
+ if (auto *Cmd = dyn_cast<SymbolAssignment>(Base1.get())) {
+ if (shouldDefine<ELFT>(Cmd))
+ addSymbol<ELFT>(Cmd);
+ continue;
+ }
- if (Cmd.Name == ".") {
- Dot = Val;
- } else {
- auto *D = cast<DefinedRegular<ELFT>>(Symtab<ELFT>::X->find(Cmd.Name));
- D->Value = Val;
- }
+ if (auto *Cmd = dyn_cast<AssertCommand>(Base1.get())) {
+ // If we don't have SECTIONS then output sections have already been
+ // created by Writer<ELFT>. The LinkerScript<ELFT>::assignAddresses
+ // will not be called, so ASSERT should be evaluated now.
+ if (!Opt.HasSections)
+ Cmd->Expression(0);
continue;
}
- // Find all the sections with required name. There can be more than
- // ont section with such name, if the alignment, flags or type
- // attribute differs.
- assert(Cmd.Kind == SectionKind);
- for (OutputSectionBase<ELFT> *Sec : Sections) {
- if (Sec->getName() != Cmd.Name)
+ if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base1.get())) {
+ std::vector<InputSectionBase<ELFT> *> V = createInputSectionList(*Cmd);
+
+ // The output section name `/DISCARD/' is special.
+ // Any input section assigned to it is discarded.
+ if (Cmd->Name == "/DISCARD/") {
+ discard(V);
continue;
+ }
- if ((Sec->getFlags() & SHF_TLS) && Sec->getType() == SHT_NOBITS) {
- uintX_t TVA = Dot + ThreadBssOffset;
- TVA = alignTo(TVA, Sec->getAlignment());
- Sec->setVA(TVA);
- ThreadBssOffset = TVA - Dot + Sec->getSize();
+ // This is for ONLY_IF_RO and ONLY_IF_RW. An output section directive
+ // ".foo : ONLY_IF_R[OW] { ... }" is handled only if all member input
+ // sections satisfy a given constraint. If not, a directive is handled
+ // as if it wasn't present from the beginning.
+ //
+ // Because we'll iterate over Commands many more times, the easiest
+ // way to "make it as if it wasn't present" is to just remove it.
+ if (!matchConstraints<ELFT>(V, Cmd->Constraint)) {
+ for (InputSectionBase<ELFT> *S : V)
+ S->Assigned = false;
+ Opt.Commands.erase(Iter);
+ --I;
continue;
}
- if (Sec->getFlags() & SHF_ALLOC) {
- Dot = alignTo(Dot, Sec->getAlignment());
- Sec->setVA(Dot);
- MinVA = std::min(MinVA, Dot);
- Dot += Sec->getSize();
+ // A directive may contain symbol definitions like this:
+ // ".foo : { ...; bar = .; }". Handle them.
+ for (const std::unique_ptr<BaseCommand> &Base : Cmd->Commands)
+ if (auto *OutCmd = dyn_cast<SymbolAssignment>(Base.get()))
+ if (shouldDefine<ELFT>(OutCmd))
+ addSymbol<ELFT>(OutCmd);
+
+ // Handle subalign (e.g. ".foo : SUBALIGN(32) { ... }"). If subalign
+ // is given, input sections are aligned to that value, whether the
+ // given value is larger or smaller than the original section alignment.
+ if (Cmd->SubalignExpr) {
+ uint32_t Subalign = Cmd->SubalignExpr(0);
+ for (InputSectionBase<ELFT> *S : V)
+ S->Alignment = Subalign;
+ }
+
+ // Add input sections to an output section.
+ for (InputSectionBase<ELFT> *S : V)
+ addSection(Factory, S, Cmd->Name);
+ }
+ }
+}
+
+// Add sections that didn't match any sections command.
+template <class ELFT>
+void LinkerScript<ELFT>::addOrphanSections(
+ OutputSectionFactory<ELFT> &Factory) {
+ for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections)
+ if (S->Live && !S->OutSec)
+ addSection(Factory, S, getOutputSectionName(S->Name));
+}
+
+// Sets value of a section-defined symbol. Two kinds of
+// symbols are processed: synthetic symbols, whose value
+// is an offset from beginning of section and regular
+// symbols whose value is absolute.
+template <class ELFT>
+static void assignSectionSymbol(SymbolAssignment *Cmd,
+ typename ELFT::uint Value) {
+ if (!Cmd->Sym)
+ return;
+
+ if (auto *Body = dyn_cast<DefinedSynthetic>(Cmd->Sym)) {
+ Body->Section = Cmd->Expression.Section();
+ Body->Value = Cmd->Expression(Value) - Body->Section->Addr;
+ return;
+ }
+ auto *Body = cast<DefinedRegular<ELFT>>(Cmd->Sym);
+ Body->Value = Cmd->Expression(Value);
+}
+
+template <class ELFT> static bool isTbss(OutputSectionBase *Sec) {
+ return (Sec->Flags & SHF_TLS) && Sec->Type == SHT_NOBITS;
+}
+
+template <class ELFT> void LinkerScript<ELFT>::output(InputSection<ELFT> *S) {
+ if (!AlreadyOutputIS.insert(S).second)
+ return;
+ bool IsTbss = isTbss<ELFT>(CurOutSec);
+
+ uintX_t Pos = IsTbss ? Dot + ThreadBssOffset : Dot;
+ Pos = alignTo(Pos, S->Alignment);
+ S->OutSecOff = Pos - CurOutSec->Addr;
+ Pos += S->getSize();
+
+ // Update output section size after adding each section. This is so that
+ // SIZEOF works correctly in the case below:
+ // .foo { *(.aaa) a = SIZEOF(.foo); *(.bbb) }
+ CurOutSec->Size = Pos - CurOutSec->Addr;
+
+ if (IsTbss)
+ ThreadBssOffset = Pos - Dot;
+ else
+ Dot = Pos;
+}
+
+template <class ELFT> void LinkerScript<ELFT>::flush() {
+ if (!CurOutSec || !AlreadyOutputOS.insert(CurOutSec).second)
+ return;
+ if (auto *OutSec = dyn_cast<OutputSection<ELFT>>(CurOutSec)) {
+ for (InputSection<ELFT> *I : OutSec->Sections)
+ output(I);
+ } else {
+ Dot += CurOutSec->Size;
+ }
+}
+
+template <class ELFT>
+void LinkerScript<ELFT>::switchTo(OutputSectionBase *Sec) {
+ if (CurOutSec == Sec)
+ return;
+ if (AlreadyOutputOS.count(Sec))
+ return;
+
+ flush();
+ CurOutSec = Sec;
+
+ Dot = alignTo(Dot, CurOutSec->Addralign);
+ CurOutSec->Addr = isTbss<ELFT>(CurOutSec) ? Dot + ThreadBssOffset : Dot;
+
+ // If neither AT nor AT> is specified for an allocatable section, the linker
+ // will set the LMA such that the difference between VMA and LMA for the
+ // section is the same as the preceding output section in the same region
+ // https://sourceware.org/binutils/docs-2.20/ld/Output-Section-LMA.html
+ CurOutSec->setLMAOffset(LMAOffset);
+}
+
+template <class ELFT> void LinkerScript<ELFT>::process(BaseCommand &Base) {
+ // This handles the assignments to symbol or to a location counter (.)
+ if (auto *AssignCmd = dyn_cast<SymbolAssignment>(&Base)) {
+ if (AssignCmd->Name == ".") {
+ // Update to location counter means update to section size.
+ uintX_t Val = AssignCmd->Expression(Dot);
+ if (Val < Dot)
+ error("unable to move location counter backward for: " +
+ CurOutSec->Name);
+ Dot = Val;
+ CurOutSec->Size = Dot - CurOutSec->Addr;
+ return;
+ }
+ assignSectionSymbol<ELFT>(AssignCmd, Dot);
+ return;
+ }
+
+ // Handle BYTE(), SHORT(), LONG(), or QUAD().
+ if (auto *DataCmd = dyn_cast<BytesDataCommand>(&Base)) {
+ DataCmd->Offset = Dot - CurOutSec->Addr;
+ Dot += DataCmd->Size;
+ CurOutSec->Size = Dot - CurOutSec->Addr;
+ return;
+ }
+
+ if (auto *AssertCmd = dyn_cast<AssertCommand>(&Base)) {
+ AssertCmd->Expression(Dot);
+ return;
+ }
+
+ // It handles single input section description command,
+ // calculates and assigns the offsets for each section and also
+ // updates the output section size.
+ auto &ICmd = cast<InputSectionDescription>(Base);
+ for (InputSectionData *ID : ICmd.Sections) {
+ // We tentatively added all synthetic sections at the beginning and removed
+ // empty ones afterwards (because there is no way to know whether they were
+ // going be empty or not other than actually running linker scripts.)
+ // We need to ignore remains of empty sections.
+ if (auto *Sec = dyn_cast<SyntheticSection<ELFT>>(ID))
+ if (Sec->empty())
continue;
+
+ auto *IB = static_cast<InputSectionBase<ELFT> *>(ID);
+ switchTo(IB->OutSec);
+ if (auto *I = dyn_cast<InputSection<ELFT>>(IB))
+ output(I);
+ else
+ flush();
+ }
+}
+
+template <class ELFT>
+static std::vector<OutputSectionBase *>
+findSections(StringRef Name, const std::vector<OutputSectionBase *> &Sections) {
+ std::vector<OutputSectionBase *> Ret;
+ for (OutputSectionBase *Sec : Sections)
+ if (Sec->getName() == Name)
+ Ret.push_back(Sec);
+ return Ret;
+}
+
+// This function assigns offsets to input sections and an output section
+// for a single sections command (e.g. ".text { *(.text); }").
+template <class ELFT>
+void LinkerScript<ELFT>::assignOffsets(OutputSectionCommand *Cmd) {
+ if (Cmd->LMAExpr)
+ LMAOffset = Cmd->LMAExpr(Dot) - Dot;
+ std::vector<OutputSectionBase *> Sections =
+ findSections<ELFT>(Cmd->Name, *OutputSections);
+ if (Sections.empty())
+ return;
+ switchTo(Sections[0]);
+
+ // Find the last section output location. We will output orphan sections
+ // there so that end symbols point to the correct location.
+ auto E = std::find_if(Cmd->Commands.rbegin(), Cmd->Commands.rend(),
+ [](const std::unique_ptr<BaseCommand> &Cmd) {
+ return !isa<SymbolAssignment>(*Cmd);
+ })
+ .base();
+ for (auto I = Cmd->Commands.begin(); I != E; ++I)
+ process(**I);
+ for (OutputSectionBase *Base : Sections)
+ switchTo(Base);
+ flush();
+ std::for_each(E, Cmd->Commands.end(),
+ [this](std::unique_ptr<BaseCommand> &B) { process(*B.get()); });
+}
+
+template <class ELFT> void LinkerScript<ELFT>::removeEmptyCommands() {
+ // It is common practice to use very generic linker scripts. So for any
+ // given run some of the output sections in the script will be empty.
+ // We could create corresponding empty output sections, but that would
+ // clutter the output.
+ // We instead remove trivially empty sections. The bfd linker seems even
+ // more aggressive at removing them.
+ auto Pos = std::remove_if(
+ Opt.Commands.begin(), Opt.Commands.end(),
+ [&](const std::unique_ptr<BaseCommand> &Base) {
+ if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
+ return findSections<ELFT>(Cmd->Name, *OutputSections).empty();
+ return false;
+ });
+ Opt.Commands.erase(Pos, Opt.Commands.end());
+}
+
+static bool isAllSectionDescription(const OutputSectionCommand &Cmd) {
+ for (const std::unique_ptr<BaseCommand> &I : Cmd.Commands)
+ if (!isa<InputSectionDescription>(*I))
+ return false;
+ return true;
+}
+
+template <class ELFT> void LinkerScript<ELFT>::adjustSectionsBeforeSorting() {
+ // If the output section contains only symbol assignments, create a
+ // corresponding output section. The bfd linker seems to only create them if
+ // '.' is assigned to, but creating these section should not have any bad
+ // consequeces and gives us a section to put the symbol in.
+ uintX_t Flags = SHF_ALLOC;
+ uint32_t Type = SHT_NOBITS;
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
+ auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
+ if (!Cmd)
+ continue;
+ std::vector<OutputSectionBase *> Secs =
+ findSections<ELFT>(Cmd->Name, *OutputSections);
+ if (!Secs.empty()) {
+ Flags = Secs[0]->Flags;
+ Type = Secs[0]->Type;
+ continue;
+ }
+
+ if (isAllSectionDescription(*Cmd))
+ continue;
+
+ auto *OutSec = make<OutputSection<ELFT>>(Cmd->Name, Type, Flags);
+ OutputSections->push_back(OutSec);
+ }
+}
+
+template <class ELFT> void LinkerScript<ELFT>::adjustSectionsAfterSorting() {
+ placeOrphanSections();
+
+ // If output section command doesn't specify any segments,
+ // and we haven't previously assigned any section to segment,
+ // then we simply assign section to the very first load segment.
+ // Below is an example of such linker script:
+ // PHDRS { seg PT_LOAD; }
+ // SECTIONS { .aaa : { *(.aaa) } }
+ std::vector<StringRef> DefPhdrs;
+ auto FirstPtLoad =
+ std::find_if(Opt.PhdrsCommands.begin(), Opt.PhdrsCommands.end(),
+ [](const PhdrsCommand &Cmd) { return Cmd.Type == PT_LOAD; });
+ if (FirstPtLoad != Opt.PhdrsCommands.end())
+ DefPhdrs.push_back(FirstPtLoad->Name);
+
+ // Walk the commands and propagate the program headers to commands that don't
+ // explicitly specify them.
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
+ auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
+ if (!Cmd)
+ continue;
+ if (Cmd->Phdrs.empty())
+ Cmd->Phdrs = DefPhdrs;
+ else
+ DefPhdrs = Cmd->Phdrs;
+ }
+
+ removeEmptyCommands();
+}
+
+// When placing orphan sections, we want to place them after symbol assignments
+// so that an orphan after
+// begin_foo = .;
+// foo : { *(foo) }
+// end_foo = .;
+// doesn't break the intended meaning of the begin/end symbols.
+// We don't want to go over sections since Writer<ELFT>::sortSections is the
+// one in charge of deciding the order of the sections.
+// We don't want to go over alignments, since doing so in
+// rx_sec : { *(rx_sec) }
+// . = ALIGN(0x1000);
+// /* The RW PT_LOAD starts here*/
+// rw_sec : { *(rw_sec) }
+// would mean that the RW PT_LOAD would become unaligned.
+static bool shouldSkip(const BaseCommand &Cmd) {
+ if (isa<OutputSectionCommand>(Cmd))
+ return false;
+ const auto *Assign = dyn_cast<SymbolAssignment>(&Cmd);
+ if (!Assign)
+ return true;
+ return Assign->Name != ".";
+}
+
+// Orphan sections are sections present in the input files which are not
+// explicitly placed into the output file by the linker script. This just
+// places them in the order already decided in OutputSections.
+template <class ELFT> void LinkerScript<ELFT>::placeOrphanSections() {
+ // The OutputSections are already in the correct order.
+ // This loops creates or moves commands as needed so that they are in the
+ // correct order.
+ int CmdIndex = 0;
+
+ // As a horrible special case, skip the first . assignment if it is before any
+ // section. We do this because it is common to set a load address by starting
+ // the script with ". = 0xabcd" and the expectation is that every section is
+ // after that.
+ auto FirstSectionOrDotAssignment =
+ std::find_if(Opt.Commands.begin(), Opt.Commands.end(),
+ [](const std::unique_ptr<BaseCommand> &Cmd) {
+ if (isa<OutputSectionCommand>(*Cmd))
+ return true;
+ const auto *Assign = dyn_cast<SymbolAssignment>(Cmd.get());
+ if (!Assign)
+ return false;
+ return Assign->Name == ".";
+ });
+ if (FirstSectionOrDotAssignment != Opt.Commands.end()) {
+ CmdIndex = FirstSectionOrDotAssignment - Opt.Commands.begin();
+ if (isa<SymbolAssignment>(**FirstSectionOrDotAssignment))
+ ++CmdIndex;
+ }
+
+ for (OutputSectionBase *Sec : *OutputSections) {
+ StringRef Name = Sec->getName();
+
+ // Find the last spot where we can insert a command and still get the
+ // correct result.
+ auto CmdIter = Opt.Commands.begin() + CmdIndex;
+ auto E = Opt.Commands.end();
+ while (CmdIter != E && shouldSkip(**CmdIter)) {
+ ++CmdIter;
+ ++CmdIndex;
+ }
+
+ auto Pos =
+ std::find_if(CmdIter, E, [&](const std::unique_ptr<BaseCommand> &Base) {
+ auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
+ return Cmd && Cmd->Name == Name;
+ });
+ if (Pos == E) {
+ Opt.Commands.insert(CmdIter,
+ llvm::make_unique<OutputSectionCommand>(Name));
+ ++CmdIndex;
+ continue;
+ }
+
+ // Continue from where we found it.
+ CmdIndex = (Pos - Opt.Commands.begin()) + 1;
+ }
+}
+
+template <class ELFT>
+void LinkerScript<ELFT>::assignAddresses(std::vector<PhdrEntry> &Phdrs) {
+ // Assign addresses as instructed by linker script SECTIONS sub-commands.
+ Dot = 0;
+
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
+ if (auto *Cmd = dyn_cast<SymbolAssignment>(Base.get())) {
+ if (Cmd->Name == ".") {
+ Dot = Cmd->Expression(Dot);
+ } else if (Cmd->Sym) {
+ assignSectionSymbol<ELFT>(Cmd, Dot);
}
+ continue;
}
+
+ if (auto *Cmd = dyn_cast<AssertCommand>(Base.get())) {
+ Cmd->Expression(Dot);
+ continue;
+ }
+
+ auto *Cmd = cast<OutputSectionCommand>(Base.get());
+ if (Cmd->AddrExpr)
+ Dot = Cmd->AddrExpr(Dot);
+ assignOffsets(Cmd);
}
+ uintX_t MinVA = std::numeric_limits<uintX_t>::max();
+ for (OutputSectionBase *Sec : *OutputSections) {
+ if (Sec->Flags & SHF_ALLOC)
+ MinVA = std::min<uint64_t>(MinVA, Sec->Addr);
+ else
+ Sec->Addr = 0;
+ }
+
+ uintX_t HeaderSize = getHeaderSize();
+ // If the linker script doesn't have PHDRS, add ElfHeader and ProgramHeaders
+ // now that we know we have space.
+ if (HeaderSize <= MinVA && !hasPhdrsCommands())
+ allocateHeaders<ELFT>(Phdrs, *OutputSections);
+
// ELF and Program headers need to be right before the first section in
- // memory.
- // Set their addresses accordingly.
- MinVA = alignDown(MinVA - Out<ELFT>::ElfHeader->getSize() -
- Out<ELFT>::ProgramHeaders->getSize(),
- Target->PageSize);
- Out<ELFT>::ElfHeader->setVA(MinVA);
- Out<ELFT>::ProgramHeaders->setVA(Out<ELFT>::ElfHeader->getSize() + MinVA);
+ // memory. Set their addresses accordingly.
+ MinVA = alignDown(MinVA - HeaderSize, Config->MaxPageSize);
+ Out<ELFT>::ElfHeader->Addr = MinVA;
+ Out<ELFT>::ProgramHeaders->Addr = Out<ELFT>::ElfHeader->Size + MinVA;
+}
+
+// Creates program headers as instructed by PHDRS linker script command.
+template <class ELFT> std::vector<PhdrEntry> LinkerScript<ELFT>::createPhdrs() {
+ std::vector<PhdrEntry> Ret;
+
+ // Process PHDRS and FILEHDR keywords because they are not
+ // real output sections and cannot be added in the following loop.
+ for (const PhdrsCommand &Cmd : Opt.PhdrsCommands) {
+ Ret.emplace_back(Cmd.Type, Cmd.Flags == UINT_MAX ? PF_R : Cmd.Flags);
+ PhdrEntry &Phdr = Ret.back();
+
+ if (Cmd.HasFilehdr)
+ Phdr.add(Out<ELFT>::ElfHeader);
+ if (Cmd.HasPhdrs)
+ Phdr.add(Out<ELFT>::ProgramHeaders);
+
+ if (Cmd.LMAExpr) {
+ Phdr.p_paddr = Cmd.LMAExpr(0);
+ Phdr.HasLMA = true;
+ }
+ }
+
+ // Add output sections to program headers.
+ for (OutputSectionBase *Sec : *OutputSections) {
+ if (!(Sec->Flags & SHF_ALLOC))
+ break;
+
+ // Assign headers specified by linker script
+ for (size_t Id : getPhdrIndices(Sec->getName())) {
+ Ret[Id].add(Sec);
+ if (Opt.PhdrsCommands[Id].Flags == UINT_MAX)
+ Ret[Id].p_flags |= Sec->getPhdrFlags();
+ }
+ }
+ return Ret;
+}
+
+template <class ELFT> bool LinkerScript<ELFT>::ignoreInterpSection() {
+ // Ignore .interp section in case we have PHDRS specification
+ // and PT_INTERP isn't listed.
+ return !Opt.PhdrsCommands.empty() &&
+ llvm::find_if(Opt.PhdrsCommands, [](const PhdrsCommand &Cmd) {
+ return Cmd.Type == PT_INTERP;
+ }) == Opt.PhdrsCommands.end();
+}
+
+template <class ELFT> uint32_t LinkerScript<ELFT>::getFiller(StringRef Name) {
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
+ if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
+ if (Cmd->Name == Name)
+ return Cmd->Filler;
+ return 0;
}
template <class ELFT>
-ArrayRef<uint8_t> LinkerScript<ELFT>::getFiller(StringRef Name) {
- auto I = Opt.Filler.find(Name);
- if (I == Opt.Filler.end())
- return {};
- return I->second;
+static void writeInt(uint8_t *Buf, uint64_t Data, uint64_t Size) {
+ const endianness E = ELFT::TargetEndianness;
+
+ switch (Size) {
+ case 1:
+ *Buf = (uint8_t)Data;
+ break;
+ case 2:
+ write16<E>(Buf, Data);
+ break;
+ case 4:
+ write32<E>(Buf, Data);
+ break;
+ case 8:
+ write64<E>(Buf, Data);
+ break;
+ default:
+ llvm_unreachable("unsupported Size argument");
+ }
+}
+
+template <class ELFT>
+void LinkerScript<ELFT>::writeDataBytes(StringRef Name, uint8_t *Buf) {
+ int I = getSectionIndex(Name);
+ if (I == INT_MAX)
+ return;
+
+ auto *Cmd = dyn_cast<OutputSectionCommand>(Opt.Commands[I].get());
+ for (const std::unique_ptr<BaseCommand> &Base : Cmd->Commands)
+ if (auto *Data = dyn_cast<BytesDataCommand>(Base.get()))
+ writeInt<ELFT>(Buf + Data->Offset, Data->Expression(0), Data->Size);
+}
+
+template <class ELFT> bool LinkerScript<ELFT>::hasLMA(StringRef Name) {
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
+ if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
+ if (Cmd->LMAExpr && Cmd->Name == Name)
+ return true;
+ return false;
}
// Returns the index of the given section name in linker script
// SECTIONS commands. Sections are laid out as the same order as they
// were in the script. If a given name did not appear in the script,
// it returns INT_MAX, so that it will be laid out at end of file.
+template <class ELFT> int LinkerScript<ELFT>::getSectionIndex(StringRef Name) {
+ for (int I = 0, E = Opt.Commands.size(); I != E; ++I)
+ if (auto *Cmd = dyn_cast<OutputSectionCommand>(Opt.Commands[I].get()))
+ if (Cmd->Name == Name)
+ return I;
+ return INT_MAX;
+}
+
+template <class ELFT> bool LinkerScript<ELFT>::hasPhdrsCommands() {
+ return !Opt.PhdrsCommands.empty();
+}
+
template <class ELFT>
-int LinkerScript<ELFT>::getSectionIndex(StringRef Name) {
- auto Begin = Opt.Commands.begin();
- auto End = Opt.Commands.end();
- auto I = std::find_if(Begin, End, [&](SectionsCommand &N) {
- return N.Kind == SectionKind && N.Name == Name;
- });
- return I == End ? INT_MAX : (I - Begin);
+const OutputSectionBase *LinkerScript<ELFT>::getOutputSection(const Twine &Loc,
+ StringRef Name) {
+ static OutputSectionBase FakeSec("", 0, 0);
+
+ for (OutputSectionBase *Sec : *OutputSections)
+ if (Sec->getName() == Name)
+ return Sec;
+
+ error(Loc + ": undefined section " + Name);
+ return &FakeSec;
+}
+
+// This function is essentially the same as getOutputSection(Name)->Size,
+// but it won't print out an error message if a given section is not found.
+//
+// Linker script does not create an output section if its content is empty.
+// We want to allow SIZEOF(.foo) where .foo is a section which happened to
+// be empty. That is why this function is different from getOutputSection().
+template <class ELFT>
+uint64_t LinkerScript<ELFT>::getOutputSectionSize(StringRef Name) {
+ for (OutputSectionBase *Sec : *OutputSections)
+ if (Sec->getName() == Name)
+ return Sec->Size;
+ return 0;
+}
+
+template <class ELFT> uint64_t LinkerScript<ELFT>::getHeaderSize() {
+ return elf::getHeaderSize<ELFT>();
}
-// A compartor to sort output sections. Returns -1 or 1 if
-// A or B are mentioned in linker script. Otherwise, returns 0.
template <class ELFT>
-int LinkerScript<ELFT>::compareSections(StringRef A, StringRef B) {
- int I = getSectionIndex(A);
- int J = getSectionIndex(B);
- if (I == INT_MAX && J == INT_MAX)
- return 0;
- return I < J ? -1 : 1;
+uint64_t LinkerScript<ELFT>::getSymbolValue(const Twine &Loc, StringRef S) {
+ if (SymbolBody *B = Symtab<ELFT>::X->find(S))
+ return B->getVA<ELFT>();
+ error(Loc + ": symbol not found: " + S);
+ return 0;
+}
+
+template <class ELFT> bool LinkerScript<ELFT>::isDefined(StringRef S) {
+ return Symtab<ELFT>::X->find(S) != nullptr;
+}
+
+template <class ELFT> bool LinkerScript<ELFT>::isAbsolute(StringRef S) {
+ SymbolBody *Sym = Symtab<ELFT>::X->find(S);
+ auto *DR = dyn_cast_or_null<DefinedRegular<ELFT>>(Sym);
+ return DR && !DR->Section;
}
+// Gets section symbol belongs to. Symbol "." doesn't belong to any
+// specific section but isn't absolute at the same time, so we try
+// to find suitable section for it as well.
template <class ELFT>
-void LinkerScript<ELFT>::addScriptedSymbols() {
- for (SectionsCommand &Cmd : Opt.Commands)
- if (Cmd.Kind == AssignmentKind)
- if (Cmd.Name != "." && Symtab<ELFT>::X->find(Cmd.Name) == nullptr)
- Symtab<ELFT>::X->addAbsolute(Cmd.Name, STV_DEFAULT);
+const OutputSectionBase *LinkerScript<ELFT>::getSymbolSection(StringRef S) {
+ SymbolBody *Sym = Symtab<ELFT>::X->find(S);
+ if (!Sym) {
+ if (OutputSections->empty())
+ return nullptr;
+ return CurOutSec ? CurOutSec : (*OutputSections)[0];
+ }
+
+ if (auto *DR = dyn_cast_or_null<DefinedRegular<ELFT>>(Sym))
+ return DR->Section ? DR->Section->OutSec : nullptr;
+ if (auto *DS = dyn_cast_or_null<DefinedSynthetic>(Sym))
+ return DS->Section;
+
+ return nullptr;
}
-class elf::ScriptParser : public ScriptParserBase {
+// Returns indices of ELF headers containing specific section, identified
+// by Name. Each index is a zero based number of ELF header listed within
+// PHDRS {} script block.
+template <class ELFT>
+std::vector<size_t> LinkerScript<ELFT>::getPhdrIndices(StringRef SectionName) {
+ for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
+ auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
+ if (!Cmd || Cmd->Name != SectionName)
+ continue;
+
+ std::vector<size_t> Ret;
+ for (StringRef PhdrName : Cmd->Phdrs)
+ Ret.push_back(getPhdrIndex(Cmd->Location, PhdrName));
+ return Ret;
+ }
+ return {};
+}
+
+template <class ELFT>
+size_t LinkerScript<ELFT>::getPhdrIndex(const Twine &Loc, StringRef PhdrName) {
+ size_t I = 0;
+ for (PhdrsCommand &Cmd : Opt.PhdrsCommands) {
+ if (Cmd.Name == PhdrName)
+ return I;
+ ++I;
+ }
+ error(Loc + ": section header '" + PhdrName + "' is not listed in PHDRS");
+ return 0;
+}
+
+class elf::ScriptParser final : public ScriptParserBase {
typedef void (ScriptParser::*Handler)();
public:
- ScriptParser(StringRef S, bool B) : ScriptParserBase(S), IsUnderSysroot(B) {}
+ ScriptParser(MemoryBufferRef MB)
+ : ScriptParserBase(MB),
+ IsUnderSysroot(isUnderSysroot(MB.getBufferIdentifier())) {}
- void run();
+ void readLinkerScript();
+ void readVersionScript();
+ void readDynamicList();
private:
void addFile(StringRef Path);
@@ -331,53 +989,130 @@ private:
void readExtern();
void readGroup();
void readInclude();
- void readNothing() {}
void readOutput();
void readOutputArch();
void readOutputFormat();
+ void readPhdrs();
void readSearchDir();
void readSections();
+ void readVersion();
+ void readVersionScriptCommand();
- void readLocationCounterValue();
- void readOutputSectionDescription(StringRef OutSec);
- void readSymbolAssignment(StringRef Name);
- std::vector<StringRef> readSectionsCommandExpr();
+ SymbolAssignment *readAssignment(StringRef Name);
+ BytesDataCommand *readBytesDataCommand(StringRef Tok);
+ uint32_t readFill();
+ OutputSectionCommand *readOutputSectionDescription(StringRef OutSec);
+ uint32_t readOutputSectionFiller(StringRef Tok);
+ std::vector<StringRef> readOutputSectionPhdrs();
+ InputSectionDescription *readInputSectionDescription(StringRef Tok);
+ StringMatcher readFilePatterns();
+ std::vector<SectionPattern> readInputSectionsList();
+ InputSectionDescription *readInputSectionRules(StringRef FilePattern);
+ unsigned readPhdrType();
+ SortSectionPolicy readSortKind();
+ SymbolAssignment *readProvideHidden(bool Provide, bool Hidden);
+ SymbolAssignment *readProvideOrAssignment(StringRef Tok);
+ void readSort();
+ Expr readAssert();
+
+ Expr readExpr();
+ Expr readExpr1(Expr Lhs, int MinPrec);
+ StringRef readParenLiteral();
+ Expr readPrimary();
+ Expr readTernary(Expr Cond);
+ Expr readParenExpr();
+
+ // For parsing version script.
+ std::vector<SymbolVersion> readVersionExtern();
+ void readAnonymousDeclaration();
+ void readVersionDeclaration(StringRef VerStr);
+ std::vector<SymbolVersion> readSymbols();
- const static StringMap<Handler> Cmd;
ScriptConfiguration &Opt = *ScriptConfig;
- StringSaver Saver = {ScriptConfig->Alloc};
bool IsUnderSysroot;
};
-const StringMap<elf::ScriptParser::Handler> elf::ScriptParser::Cmd = {
- {"ENTRY", &ScriptParser::readEntry},
- {"EXTERN", &ScriptParser::readExtern},
- {"GROUP", &ScriptParser::readGroup},
- {"INCLUDE", &ScriptParser::readInclude},
- {"INPUT", &ScriptParser::readGroup},
- {"OUTPUT", &ScriptParser::readOutput},
- {"OUTPUT_ARCH", &ScriptParser::readOutputArch},
- {"OUTPUT_FORMAT", &ScriptParser::readOutputFormat},
- {"SEARCH_DIR", &ScriptParser::readSearchDir},
- {"SECTIONS", &ScriptParser::readSections},
- {";", &ScriptParser::readNothing}};
-
-void ScriptParser::run() {
+void ScriptParser::readDynamicList() {
+ expect("{");
+ readAnonymousDeclaration();
+ if (!atEOF())
+ setError("EOF expected, but got " + next());
+}
+
+void ScriptParser::readVersionScript() {
+ readVersionScriptCommand();
+ if (!atEOF())
+ setError("EOF expected, but got " + next());
+}
+
+void ScriptParser::readVersionScriptCommand() {
+ if (consume("{")) {
+ readAnonymousDeclaration();
+ return;
+ }
+
+ while (!atEOF() && !Error && peek() != "}") {
+ StringRef VerStr = next();
+ if (VerStr == "{") {
+ setError("anonymous version definition is used in "
+ "combination with other version definitions");
+ return;
+ }
+ expect("{");
+ readVersionDeclaration(VerStr);
+ }
+}
+
+void ScriptParser::readVersion() {
+ expect("{");
+ readVersionScriptCommand();
+ expect("}");
+}
+
+void ScriptParser::readLinkerScript() {
while (!atEOF()) {
StringRef Tok = next();
- if (Handler Fn = Cmd.lookup(Tok))
- (this->*Fn)();
- else
+ if (Tok == ";")
+ continue;
+
+ if (Tok == "ASSERT") {
+ Opt.Commands.emplace_back(new AssertCommand(readAssert()));
+ } else if (Tok == "ENTRY") {
+ readEntry();
+ } else if (Tok == "EXTERN") {
+ readExtern();
+ } else if (Tok == "GROUP" || Tok == "INPUT") {
+ readGroup();
+ } else if (Tok == "INCLUDE") {
+ readInclude();
+ } else if (Tok == "OUTPUT") {
+ readOutput();
+ } else if (Tok == "OUTPUT_ARCH") {
+ readOutputArch();
+ } else if (Tok == "OUTPUT_FORMAT") {
+ readOutputFormat();
+ } else if (Tok == "PHDRS") {
+ readPhdrs();
+ } else if (Tok == "SEARCH_DIR") {
+ readSearchDir();
+ } else if (Tok == "SECTIONS") {
+ readSections();
+ } else if (Tok == "VERSION") {
+ readVersion();
+ } else if (SymbolAssignment *Cmd = readProvideOrAssignment(Tok)) {
+ Opt.Commands.emplace_back(Cmd);
+ } else {
setError("unknown directive: " + Tok);
+ }
}
}
void ScriptParser::addFile(StringRef S) {
if (IsUnderSysroot && S.startswith("/")) {
- SmallString<128> Path;
- (Config->Sysroot + S).toStringRef(Path);
+ SmallString<128> PathData;
+ StringRef Path = (Config->Sysroot + S).toStringRef(PathData);
if (sys::fs::exists(Path)) {
- Driver->addFile(Saver.save(Path.str()));
+ Driver->addFile(Saver.save(Path));
return;
}
}
@@ -394,11 +1129,10 @@ void ScriptParser::addFile(StringRef S) {
} else if (sys::fs::exists(S)) {
Driver->addFile(S);
} else {
- std::string Path = findFromSearchPaths(S);
- if (Path.empty())
- setError("unable to find " + S);
+ if (Optional<std::string> Path = findFromSearchPaths(S))
+ Driver->addFile(Saver.save(*Path));
else
- Driver->addFile(Saver.save(Path));
+ setError("unable to find " + S);
}
}
@@ -406,12 +1140,8 @@ void ScriptParser::readAsNeeded() {
expect("(");
bool Orig = Config->AsNeeded;
Config->AsNeeded = true;
- while (!Error) {
- StringRef Tok = next();
- if (Tok == ")")
- break;
- addFile(Tok);
- }
+ while (!Error && !consume(")"))
+ addFile(unquote(next()));
Config->AsNeeded = Orig;
}
@@ -426,39 +1156,37 @@ void ScriptParser::readEntry() {
void ScriptParser::readExtern() {
expect("(");
- while (!Error) {
- StringRef Tok = next();
- if (Tok == ")")
- return;
- Config->Undefined.push_back(Tok);
- }
+ while (!Error && !consume(")"))
+ Config->Undefined.push_back(next());
}
void ScriptParser::readGroup() {
expect("(");
- while (!Error) {
+ while (!Error && !consume(")")) {
StringRef Tok = next();
- if (Tok == ")")
- return;
- if (Tok == "AS_NEEDED") {
+ if (Tok == "AS_NEEDED")
readAsNeeded();
- continue;
- }
- addFile(Tok);
+ else
+ addFile(unquote(Tok));
}
}
void ScriptParser::readInclude() {
- StringRef Tok = next();
+ StringRef Tok = unquote(next());
+ // https://sourceware.org/binutils/docs/ld/File-Commands.html:
+ // The file will be searched for in the current directory, and in any
+ // directory specified with the -L option.
auto MBOrErr = MemoryBuffer::getFile(Tok);
+ if (!MBOrErr)
+ if (Optional<std::string> Path = findFromSearchPaths(Tok))
+ MBOrErr = MemoryBuffer::getFile(*Path);
if (!MBOrErr) {
setError("cannot open " + Tok);
return;
}
- std::unique_ptr<MemoryBuffer> &MB = *MBOrErr;
- StringRef S = Saver.save(MB->getMemBufferRef().getBuffer());
- std::vector<StringRef> V = tokenize(S);
- Tokens.insert(Tokens.begin() + Pos, V.begin(), V.end());
+ MemoryBufferRef MBRef = (*MBOrErr)->getMemBufferRef();
+ make<std::unique_ptr<MemoryBuffer>>(std::move(*MBOrErr)); // take MB ownership
+ tokenize(MBRef);
}
void ScriptParser::readOutput() {
@@ -466,138 +1194,782 @@ void ScriptParser::readOutput() {
expect("(");
StringRef Tok = next();
if (Config->OutputFile.empty())
- Config->OutputFile = Tok;
+ Config->OutputFile = unquote(Tok);
expect(")");
}
void ScriptParser::readOutputArch() {
// Error checking only for now.
expect("(");
- next();
+ skip();
expect(")");
}
void ScriptParser::readOutputFormat() {
// Error checking only for now.
expect("(");
- next();
+ skip();
StringRef Tok = next();
if (Tok == ")")
- return;
+ return;
if (Tok != ",") {
setError("unexpected token: " + Tok);
return;
}
- next();
+ skip();
expect(",");
- next();
+ skip();
expect(")");
}
+void ScriptParser::readPhdrs() {
+ expect("{");
+ while (!Error && !consume("}")) {
+ StringRef Tok = next();
+ Opt.PhdrsCommands.push_back(
+ {Tok, PT_NULL, false, false, UINT_MAX, nullptr});
+ PhdrsCommand &PhdrCmd = Opt.PhdrsCommands.back();
+
+ PhdrCmd.Type = readPhdrType();
+ do {
+ Tok = next();
+ if (Tok == ";")
+ break;
+ if (Tok == "FILEHDR")
+ PhdrCmd.HasFilehdr = true;
+ else if (Tok == "PHDRS")
+ PhdrCmd.HasPhdrs = true;
+ else if (Tok == "AT")
+ PhdrCmd.LMAExpr = readParenExpr();
+ else if (Tok == "FLAGS") {
+ expect("(");
+ // Passing 0 for the value of dot is a bit of a hack. It means that
+ // we accept expressions like ".|1".
+ PhdrCmd.Flags = readExpr()(0);
+ expect(")");
+ } else
+ setError("unexpected header attribute: " + Tok);
+ } while (!Error);
+ }
+}
+
void ScriptParser::readSearchDir() {
expect("(");
- Config->SearchPaths.push_back(next());
+ StringRef Tok = next();
+ if (!Config->Nostdlib)
+ Config->SearchPaths.push_back(unquote(Tok));
expect(")");
}
void ScriptParser::readSections() {
- Opt.DoLayout = true;
+ Opt.HasSections = true;
+ // -no-rosegment is used to avoid placing read only non-executable sections in
+ // their own segment. We do the same if SECTIONS command is present in linker
+ // script. See comment for computeFlags().
+ Config->SingleRoRx = true;
+
expect("{");
- while (!Error && !skip("}")) {
- StringRef Tok = peek();
- if (Tok == ".") {
- readLocationCounterValue();
- continue;
+ while (!Error && !consume("}")) {
+ StringRef Tok = next();
+ BaseCommand *Cmd = readProvideOrAssignment(Tok);
+ if (!Cmd) {
+ if (Tok == "ASSERT")
+ Cmd = new AssertCommand(readAssert());
+ else
+ Cmd = readOutputSectionDescription(Tok);
}
- next();
- if (peek() == "=")
- readSymbolAssignment(Tok);
- else
- readOutputSectionDescription(Tok);
+ Opt.Commands.emplace_back(Cmd);
}
}
-void ScriptParser::readLocationCounterValue() {
- expect(".");
- expect("=");
- std::vector<StringRef> Expr = readSectionsCommandExpr();
- if (Expr.empty())
- error("error in location counter expression");
- else
- Opt.Commands.push_back({AssignmentKind, std::move(Expr), "."});
+static int precedence(StringRef Op) {
+ return StringSwitch<int>(Op)
+ .Cases("*", "/", 5)
+ .Cases("+", "-", 4)
+ .Cases("<<", ">>", 3)
+ .Cases("<", "<=", ">", ">=", "==", "!=", 2)
+ .Cases("&", "|", 1)
+ .Default(-1);
}
-void ScriptParser::readOutputSectionDescription(StringRef OutSec) {
- Opt.Commands.push_back({SectionKind, {}, OutSec});
- expect(":");
- expect("{");
+StringMatcher ScriptParser::readFilePatterns() {
+ std::vector<StringRef> V;
+ while (!Error && !consume(")"))
+ V.push_back(next());
+ return StringMatcher(V);
+}
- while (!Error && !skip("}")) {
- StringRef Tok = next();
- if (Tok == "*") {
- expect("(");
- while (!Error && !skip(")"))
- Opt.Sections.emplace_back(OutSec, next());
- } else if (Tok == "KEEP") {
+SortSectionPolicy ScriptParser::readSortKind() {
+ if (consume("SORT") || consume("SORT_BY_NAME"))
+ return SortSectionPolicy::Name;
+ if (consume("SORT_BY_ALIGNMENT"))
+ return SortSectionPolicy::Alignment;
+ if (consume("SORT_BY_INIT_PRIORITY"))
+ return SortSectionPolicy::Priority;
+ if (consume("SORT_NONE"))
+ return SortSectionPolicy::None;
+ return SortSectionPolicy::Default;
+}
+
+// Method reads a list of sequence of excluded files and section globs given in
+// a following form: ((EXCLUDE_FILE(file_pattern+))? section_pattern+)+
+// Example: *(.foo.1 EXCLUDE_FILE (*a.o) .foo.2 EXCLUDE_FILE (*b.o) .foo.3)
+// The semantics of that is next:
+// * Include .foo.1 from every file.
+// * Include .foo.2 from every file but a.o
+// * Include .foo.3 from every file but b.o
+std::vector<SectionPattern> ScriptParser::readInputSectionsList() {
+ std::vector<SectionPattern> Ret;
+ while (!Error && peek() != ")") {
+ StringMatcher ExcludeFilePat;
+ if (consume("EXCLUDE_FILE")) {
expect("(");
- expect("*");
+ ExcludeFilePat = readFilePatterns();
+ }
+
+ std::vector<StringRef> V;
+ while (!Error && peek() != ")" && peek() != "EXCLUDE_FILE")
+ V.push_back(next());
+
+ if (!V.empty())
+ Ret.push_back({std::move(ExcludeFilePat), StringMatcher(V)});
+ else
+ setError("section pattern is expected");
+ }
+ return Ret;
+}
+
+// Reads contents of "SECTIONS" directive. That directive contains a
+// list of glob patterns for input sections. The grammar is as follows.
+//
+// <patterns> ::= <section-list>
+// | <sort> "(" <section-list> ")"
+// | <sort> "(" <sort> "(" <section-list> ")" ")"
+//
+// <sort> ::= "SORT" | "SORT_BY_NAME" | "SORT_BY_ALIGNMENT"
+// | "SORT_BY_INIT_PRIORITY" | "SORT_NONE"
+//
+// <section-list> is parsed by readInputSectionsList().
+InputSectionDescription *
+ScriptParser::readInputSectionRules(StringRef FilePattern) {
+ auto *Cmd = new InputSectionDescription(FilePattern);
+ expect("(");
+ while (!Error && !consume(")")) {
+ SortSectionPolicy Outer = readSortKind();
+ SortSectionPolicy Inner = SortSectionPolicy::Default;
+ std::vector<SectionPattern> V;
+ if (Outer != SortSectionPolicy::Default) {
expect("(");
- while (!Error && !skip(")")) {
- StringRef Sec = next();
- Opt.Sections.emplace_back(OutSec, Sec);
- Opt.KeptSections.push_back(Sec);
+ Inner = readSortKind();
+ if (Inner != SortSectionPolicy::Default) {
+ expect("(");
+ V = readInputSectionsList();
+ expect(")");
+ } else {
+ V = readInputSectionsList();
}
expect(")");
} else {
+ V = readInputSectionsList();
+ }
+
+ for (SectionPattern &Pat : V) {
+ Pat.SortInner = Inner;
+ Pat.SortOuter = Outer;
+ }
+
+ std::move(V.begin(), V.end(), std::back_inserter(Cmd->SectionPatterns));
+ }
+ return Cmd;
+}
+
+InputSectionDescription *
+ScriptParser::readInputSectionDescription(StringRef Tok) {
+ // Input section wildcard can be surrounded by KEEP.
+ // https://sourceware.org/binutils/docs/ld/Input-Section-Keep.html#Input-Section-Keep
+ if (Tok == "KEEP") {
+ expect("(");
+ StringRef FilePattern = next();
+ InputSectionDescription *Cmd = readInputSectionRules(FilePattern);
+ expect(")");
+ Opt.KeptSections.push_back(Cmd);
+ return Cmd;
+ }
+ return readInputSectionRules(Tok);
+}
+
+void ScriptParser::readSort() {
+ expect("(");
+ expect("CONSTRUCTORS");
+ expect(")");
+}
+
+Expr ScriptParser::readAssert() {
+ expect("(");
+ Expr E = readExpr();
+ expect(",");
+ StringRef Msg = unquote(next());
+ expect(")");
+ return [=](uint64_t Dot) {
+ uint64_t V = E(Dot);
+ if (!V)
+ error(Msg);
+ return V;
+ };
+}
+
+// Reads a FILL(expr) command. We handle the FILL command as an
+// alias for =fillexp section attribute, which is different from
+// what GNU linkers do.
+// https://sourceware.org/binutils/docs/ld/Output-Section-Data.html
+uint32_t ScriptParser::readFill() {
+ expect("(");
+ uint32_t V = readOutputSectionFiller(next());
+ expect(")");
+ expect(";");
+ return V;
+}
+
+OutputSectionCommand *
+ScriptParser::readOutputSectionDescription(StringRef OutSec) {
+ OutputSectionCommand *Cmd = new OutputSectionCommand(OutSec);
+ Cmd->Location = getCurrentLocation();
+
+ // Read an address expression.
+ // https://sourceware.org/binutils/docs/ld/Output-Section-Address.html#Output-Section-Address
+ if (peek() != ":")
+ Cmd->AddrExpr = readExpr();
+
+ expect(":");
+
+ if (consume("AT"))
+ Cmd->LMAExpr = readParenExpr();
+ if (consume("ALIGN"))
+ Cmd->AlignExpr = readParenExpr();
+ if (consume("SUBALIGN"))
+ Cmd->SubalignExpr = readParenExpr();
+
+ // Parse constraints.
+ if (consume("ONLY_IF_RO"))
+ Cmd->Constraint = ConstraintKind::ReadOnly;
+ if (consume("ONLY_IF_RW"))
+ Cmd->Constraint = ConstraintKind::ReadWrite;
+ expect("{");
+
+ while (!Error && !consume("}")) {
+ StringRef Tok = next();
+ if (SymbolAssignment *Assignment = readProvideOrAssignment(Tok)) {
+ Cmd->Commands.emplace_back(Assignment);
+ } else if (BytesDataCommand *Data = readBytesDataCommand(Tok)) {
+ Cmd->Commands.emplace_back(Data);
+ } else if (Tok == "ASSERT") {
+ Cmd->Commands.emplace_back(new AssertCommand(readAssert()));
+ expect(";");
+ } else if (Tok == "FILL") {
+ Cmd->Filler = readFill();
+ } else if (Tok == "SORT") {
+ readSort();
+ } else if (peek() == "(") {
+ Cmd->Commands.emplace_back(readInputSectionDescription(Tok));
+ } else {
setError("unknown command " + Tok);
}
}
+ Cmd->Phdrs = readOutputSectionPhdrs();
- StringRef Tok = peek();
- if (Tok.startswith("=")) {
- if (!Tok.startswith("=0x")) {
- setError("filler should be a hexadecimal value");
- return;
+ if (consume("="))
+ Cmd->Filler = readOutputSectionFiller(next());
+ else if (peek().startswith("="))
+ Cmd->Filler = readOutputSectionFiller(next().drop_front());
+
+ return Cmd;
+}
+
+// Read "=<number>" where <number> is an octal/decimal/hexadecimal number.
+// https://sourceware.org/binutils/docs/ld/Output-Section-Fill.html
+//
+// ld.gold is not fully compatible with ld.bfd. ld.bfd handles
+// hexstrings as blobs of arbitrary sizes, while ld.gold handles them
+// as 32-bit big-endian values. We will do the same as ld.gold does
+// because it's simpler than what ld.bfd does.
+uint32_t ScriptParser::readOutputSectionFiller(StringRef Tok) {
+ uint32_t V;
+ if (!Tok.getAsInteger(0, V))
+ return V;
+ setError("invalid filler expression: " + Tok);
+ return 0;
+}
+
+SymbolAssignment *ScriptParser::readProvideHidden(bool Provide, bool Hidden) {
+ expect("(");
+ SymbolAssignment *Cmd = readAssignment(next());
+ Cmd->Provide = Provide;
+ Cmd->Hidden = Hidden;
+ expect(")");
+ expect(";");
+ return Cmd;
+}
+
+SymbolAssignment *ScriptParser::readProvideOrAssignment(StringRef Tok) {
+ SymbolAssignment *Cmd = nullptr;
+ if (peek() == "=" || peek() == "+=") {
+ Cmd = readAssignment(Tok);
+ expect(";");
+ } else if (Tok == "PROVIDE") {
+ Cmd = readProvideHidden(true, false);
+ } else if (Tok == "HIDDEN") {
+ Cmd = readProvideHidden(false, true);
+ } else if (Tok == "PROVIDE_HIDDEN") {
+ Cmd = readProvideHidden(true, true);
+ }
+ return Cmd;
+}
+
+static uint64_t getSymbolValue(const Twine &Loc, StringRef S, uint64_t Dot) {
+ if (S == ".")
+ return Dot;
+ return ScriptBase->getSymbolValue(Loc, S);
+}
+
+static bool isAbsolute(StringRef S) {
+ if (S == ".")
+ return false;
+ return ScriptBase->isAbsolute(S);
+}
+
+SymbolAssignment *ScriptParser::readAssignment(StringRef Name) {
+ StringRef Op = next();
+ Expr E;
+ assert(Op == "=" || Op == "+=");
+ if (consume("ABSOLUTE")) {
+ // The RHS may be something like "ABSOLUTE(.) & 0xff".
+ // Call readExpr1 to read the whole expression.
+ E = readExpr1(readParenExpr(), 0);
+ E.IsAbsolute = [] { return true; };
+ } else {
+ E = readExpr();
+ }
+ if (Op == "+=") {
+ std::string Loc = getCurrentLocation();
+ E = [=](uint64_t Dot) {
+ return getSymbolValue(Loc, Name, Dot) + E(Dot);
+ };
+ }
+ return new SymbolAssignment(Name, E);
+}
+
+// This is an operator-precedence parser to parse a linker
+// script expression.
+Expr ScriptParser::readExpr() { return readExpr1(readPrimary(), 0); }
+
+static Expr combine(StringRef Op, Expr L, Expr R) {
+ if (Op == "*")
+ return [=](uint64_t Dot) { return L(Dot) * R(Dot); };
+ if (Op == "/") {
+ return [=](uint64_t Dot) -> uint64_t {
+ uint64_t RHS = R(Dot);
+ if (RHS == 0) {
+ error("division by zero");
+ return 0;
+ }
+ return L(Dot) / RHS;
+ };
+ }
+ if (Op == "+")
+ return {[=](uint64_t Dot) { return L(Dot) + R(Dot); },
+ [=] { return L.IsAbsolute() && R.IsAbsolute(); },
+ [=] {
+ const OutputSectionBase *S = L.Section();
+ return S ? S : R.Section();
+ }};
+ if (Op == "-")
+ return [=](uint64_t Dot) { return L(Dot) - R(Dot); };
+ if (Op == "<<")
+ return [=](uint64_t Dot) { return L(Dot) << R(Dot); };
+ if (Op == ">>")
+ return [=](uint64_t Dot) { return L(Dot) >> R(Dot); };
+ if (Op == "<")
+ return [=](uint64_t Dot) { return L(Dot) < R(Dot); };
+ if (Op == ">")
+ return [=](uint64_t Dot) { return L(Dot) > R(Dot); };
+ if (Op == ">=")
+ return [=](uint64_t Dot) { return L(Dot) >= R(Dot); };
+ if (Op == "<=")
+ return [=](uint64_t Dot) { return L(Dot) <= R(Dot); };
+ if (Op == "==")
+ return [=](uint64_t Dot) { return L(Dot) == R(Dot); };
+ if (Op == "!=")
+ return [=](uint64_t Dot) { return L(Dot) != R(Dot); };
+ if (Op == "&")
+ return [=](uint64_t Dot) { return L(Dot) & R(Dot); };
+ if (Op == "|")
+ return [=](uint64_t Dot) { return L(Dot) | R(Dot); };
+ llvm_unreachable("invalid operator");
+}
+
+// This is a part of the operator-precedence parser. This function
+// assumes that the remaining token stream starts with an operator.
+Expr ScriptParser::readExpr1(Expr Lhs, int MinPrec) {
+ while (!atEOF() && !Error) {
+ // Read an operator and an expression.
+ if (consume("?"))
+ return readTernary(Lhs);
+ StringRef Op1 = peek();
+ if (precedence(Op1) < MinPrec)
+ break;
+ skip();
+ Expr Rhs = readPrimary();
+
+ // Evaluate the remaining part of the expression first if the
+ // next operator has greater precedence than the previous one.
+ // For example, if we have read "+" and "3", and if the next
+ // operator is "*", then we'll evaluate 3 * ... part first.
+ while (!atEOF()) {
+ StringRef Op2 = peek();
+ if (precedence(Op2) <= precedence(Op1))
+ break;
+ Rhs = readExpr1(Rhs, precedence(Op2));
}
- Tok = Tok.substr(3);
- Opt.Filler[OutSec] = parseHex(Tok);
- next();
+
+ Lhs = combine(Op1, Lhs, Rhs);
}
+ return Lhs;
}
-void ScriptParser::readSymbolAssignment(StringRef Name) {
- expect("=");
- std::vector<StringRef> Expr = readSectionsCommandExpr();
- if (Expr.empty())
- error("error in symbol assignment expression");
- else
- Opt.Commands.push_back({AssignmentKind, std::move(Expr), Name});
+uint64_t static getConstant(StringRef S) {
+ if (S == "COMMONPAGESIZE")
+ return Target->PageSize;
+ if (S == "MAXPAGESIZE")
+ return Config->MaxPageSize;
+ error("unknown constant: " + S);
+ return 0;
+}
+
+// Parses Tok as an integer. Returns true if successful.
+// It recognizes hexadecimal (prefixed with "0x" or suffixed with "H")
+// and decimal numbers. Decimal numbers may have "K" (kilo) or
+// "M" (mega) prefixes.
+static bool readInteger(StringRef Tok, uint64_t &Result) {
+ // Negative number
+ if (Tok.startswith("-")) {
+ if (!readInteger(Tok.substr(1), Result))
+ return false;
+ Result = -Result;
+ return true;
+ }
+
+ // Hexadecimal
+ if (Tok.startswith_lower("0x"))
+ return !Tok.substr(2).getAsInteger(16, Result);
+ if (Tok.endswith_lower("H"))
+ return !Tok.drop_back().getAsInteger(16, Result);
+
+ // Decimal
+ int Suffix = 1;
+ if (Tok.endswith_lower("K")) {
+ Suffix = 1024;
+ Tok = Tok.drop_back();
+ } else if (Tok.endswith_lower("M")) {
+ Suffix = 1024 * 1024;
+ Tok = Tok.drop_back();
+ }
+ if (Tok.getAsInteger(10, Result))
+ return false;
+ Result *= Suffix;
+ return true;
+}
+
+BytesDataCommand *ScriptParser::readBytesDataCommand(StringRef Tok) {
+ int Size = StringSwitch<unsigned>(Tok)
+ .Case("BYTE", 1)
+ .Case("SHORT", 2)
+ .Case("LONG", 4)
+ .Case("QUAD", 8)
+ .Default(-1);
+ if (Size == -1)
+ return nullptr;
+
+ return new BytesDataCommand(readParenExpr(), Size);
+}
+
+StringRef ScriptParser::readParenLiteral() {
+ expect("(");
+ StringRef Tok = next();
+ expect(")");
+ return Tok;
+}
+
+Expr ScriptParser::readPrimary() {
+ if (peek() == "(")
+ return readParenExpr();
+
+ StringRef Tok = next();
+ std::string Location = getCurrentLocation();
+
+ if (Tok == "~") {
+ Expr E = readPrimary();
+ return [=](uint64_t Dot) { return ~E(Dot); };
+ }
+ if (Tok == "-") {
+ Expr E = readPrimary();
+ return [=](uint64_t Dot) { return -E(Dot); };
+ }
+
+ // Built-in functions are parsed here.
+ // https://sourceware.org/binutils/docs/ld/Builtin-Functions.html.
+ if (Tok == "ADDR") {
+ StringRef Name = readParenLiteral();
+ return {[=](uint64_t Dot) {
+ return ScriptBase->getOutputSection(Location, Name)->Addr;
+ },
+ [=] { return false; },
+ [=] { return ScriptBase->getOutputSection(Location, Name); }};
+ }
+ if (Tok == "LOADADDR") {
+ StringRef Name = readParenLiteral();
+ return [=](uint64_t Dot) {
+ return ScriptBase->getOutputSection(Location, Name)->getLMA();
+ };
+ }
+ if (Tok == "ASSERT")
+ return readAssert();
+ if (Tok == "ALIGN") {
+ expect("(");
+ Expr E = readExpr();
+ if (consume(",")) {
+ Expr E2 = readExpr();
+ expect(")");
+ return [=](uint64_t Dot) { return alignTo(E(Dot), E2(Dot)); };
+ }
+ expect(")");
+ return [=](uint64_t Dot) { return alignTo(Dot, E(Dot)); };
+ }
+ if (Tok == "CONSTANT") {
+ StringRef Name = readParenLiteral();
+ return [=](uint64_t Dot) { return getConstant(Name); };
+ }
+ if (Tok == "DEFINED") {
+ StringRef Name = readParenLiteral();
+ return [=](uint64_t Dot) { return ScriptBase->isDefined(Name) ? 1 : 0; };
+ }
+ if (Tok == "SEGMENT_START") {
+ expect("(");
+ skip();
+ expect(",");
+ Expr E = readExpr();
+ expect(")");
+ return [=](uint64_t Dot) { return E(Dot); };
+ }
+ if (Tok == "DATA_SEGMENT_ALIGN") {
+ expect("(");
+ Expr E = readExpr();
+ expect(",");
+ readExpr();
+ expect(")");
+ return [=](uint64_t Dot) { return alignTo(Dot, E(Dot)); };
+ }
+ if (Tok == "DATA_SEGMENT_END") {
+ expect("(");
+ expect(".");
+ expect(")");
+ return [](uint64_t Dot) { return Dot; };
+ }
+ // GNU linkers implements more complicated logic to handle
+ // DATA_SEGMENT_RELRO_END. We instead ignore the arguments and just align to
+ // the next page boundary for simplicity.
+ if (Tok == "DATA_SEGMENT_RELRO_END") {
+ expect("(");
+ readExpr();
+ expect(",");
+ readExpr();
+ expect(")");
+ return [](uint64_t Dot) { return alignTo(Dot, Target->PageSize); };
+ }
+ if (Tok == "SIZEOF") {
+ StringRef Name = readParenLiteral();
+ return [=](uint64_t Dot) { return ScriptBase->getOutputSectionSize(Name); };
+ }
+ if (Tok == "ALIGNOF") {
+ StringRef Name = readParenLiteral();
+ return [=](uint64_t Dot) {
+ return ScriptBase->getOutputSection(Location, Name)->Addralign;
+ };
+ }
+ if (Tok == "SIZEOF_HEADERS")
+ return [=](uint64_t Dot) { return ScriptBase->getHeaderSize(); };
+
+ // Tok is a literal number.
+ uint64_t V;
+ if (readInteger(Tok, V))
+ return [=](uint64_t Dot) { return V; };
+
+ // Tok is a symbol name.
+ if (Tok != "." && !isValidCIdentifier(Tok))
+ setError("malformed number: " + Tok);
+ return {[=](uint64_t Dot) { return getSymbolValue(Location, Tok, Dot); },
+ [=] { return isAbsolute(Tok); },
+ [=] { return ScriptBase->getSymbolSection(Tok); }};
}
-std::vector<StringRef> ScriptParser::readSectionsCommandExpr() {
- std::vector<StringRef> Expr;
- while (!Error) {
+Expr ScriptParser::readTernary(Expr Cond) {
+ Expr L = readExpr();
+ expect(":");
+ Expr R = readExpr();
+ return [=](uint64_t Dot) { return Cond(Dot) ? L(Dot) : R(Dot); };
+}
+
+Expr ScriptParser::readParenExpr() {
+ expect("(");
+ Expr E = readExpr();
+ expect(")");
+ return E;
+}
+
+std::vector<StringRef> ScriptParser::readOutputSectionPhdrs() {
+ std::vector<StringRef> Phdrs;
+ while (!Error && peek().startswith(":")) {
StringRef Tok = next();
- if (Tok == ";")
+ Phdrs.push_back((Tok.size() == 1) ? next() : Tok.substr(1));
+ }
+ return Phdrs;
+}
+
+// Read a program header type name. The next token must be a
+// name of a program header type or a constant (e.g. "0x3").
+unsigned ScriptParser::readPhdrType() {
+ StringRef Tok = next();
+ uint64_t Val;
+ if (readInteger(Tok, Val))
+ return Val;
+
+ unsigned Ret = StringSwitch<unsigned>(Tok)
+ .Case("PT_NULL", PT_NULL)
+ .Case("PT_LOAD", PT_LOAD)
+ .Case("PT_DYNAMIC", PT_DYNAMIC)
+ .Case("PT_INTERP", PT_INTERP)
+ .Case("PT_NOTE", PT_NOTE)
+ .Case("PT_SHLIB", PT_SHLIB)
+ .Case("PT_PHDR", PT_PHDR)
+ .Case("PT_TLS", PT_TLS)
+ .Case("PT_GNU_EH_FRAME", PT_GNU_EH_FRAME)
+ .Case("PT_GNU_STACK", PT_GNU_STACK)
+ .Case("PT_GNU_RELRO", PT_GNU_RELRO)
+ .Case("PT_OPENBSD_RANDOMIZE", PT_OPENBSD_RANDOMIZE)
+ .Case("PT_OPENBSD_WXNEEDED", PT_OPENBSD_WXNEEDED)
+ .Case("PT_OPENBSD_BOOTDATA", PT_OPENBSD_BOOTDATA)
+ .Default(-1);
+
+ if (Ret == (unsigned)-1) {
+ setError("invalid program header type: " + Tok);
+ return PT_NULL;
+ }
+ return Ret;
+}
+
+// Reads a list of symbols, e.g. "{ global: foo; bar; local: *; };".
+void ScriptParser::readAnonymousDeclaration() {
+ // Read global symbols first. "global:" is default, so if there's
+ // no label, we assume global symbols.
+ if (consume("global:") || peek() != "local:")
+ Config->VersionScriptGlobals = readSymbols();
+
+ // Next, read local symbols.
+ if (consume("local:")) {
+ if (consume("*")) {
+ Config->DefaultSymbolVersion = VER_NDX_LOCAL;
+ expect(";");
+ } else {
+ setError("local symbol list for anonymous version is not supported");
+ }
+ }
+ expect("}");
+ expect(";");
+}
+
+// Reads a list of symbols, e.g. "VerStr { global: foo; bar; local: *; };".
+void ScriptParser::readVersionDeclaration(StringRef VerStr) {
+ // Identifiers start at 2 because 0 and 1 are reserved
+ // for VER_NDX_LOCAL and VER_NDX_GLOBAL constants.
+ uint16_t VersionId = Config->VersionDefinitions.size() + 2;
+ Config->VersionDefinitions.push_back({VerStr, VersionId});
+
+ // Read global symbols.
+ if (consume("global:") || peek() != "local:")
+ Config->VersionDefinitions.back().Globals = readSymbols();
+
+ // Read local symbols.
+ if (consume("local:")) {
+ if (consume("*")) {
+ Config->DefaultSymbolVersion = VER_NDX_LOCAL;
+ expect(";");
+ } else {
+ for (SymbolVersion V : readSymbols())
+ Config->VersionScriptLocals.push_back(V);
+ }
+ }
+ expect("}");
+
+ // Each version may have a parent version. For example, "Ver2"
+ // defined as "Ver2 { global: foo; local: *; } Ver1;" has "Ver1"
+ // as a parent. This version hierarchy is, probably against your
+ // instinct, purely for hint; the runtime doesn't care about it
+ // at all. In LLD, we simply ignore it.
+ if (peek() != ";")
+ skip();
+ expect(";");
+}
+
+// Reads a list of symbols for a versions cript.
+std::vector<SymbolVersion> ScriptParser::readSymbols() {
+ std::vector<SymbolVersion> Ret;
+ for (;;) {
+ if (consume("extern")) {
+ for (SymbolVersion V : readVersionExtern())
+ Ret.push_back(V);
+ continue;
+ }
+
+ if (peek() == "}" || peek() == "local:" || Error)
break;
- Expr.push_back(Tok);
+ StringRef Tok = next();
+ Ret.push_back({unquote(Tok), false, hasWildcard(Tok)});
+ expect(";");
}
- return Expr;
+ return Ret;
}
-static bool isUnderSysroot(StringRef Path) {
- if (Config->Sysroot == "")
- return false;
- for (; !Path.empty(); Path = sys::path::parent_path(Path))
- if (sys::fs::equivalent(Config->Sysroot, Path))
- return true;
- return false;
+// Reads an "extern C++" directive, e.g.,
+// "extern "C++" { ns::*; "f(int, double)"; };"
+std::vector<SymbolVersion> ScriptParser::readVersionExtern() {
+ StringRef Tok = next();
+ bool IsCXX = Tok == "\"C++\"";
+ if (!IsCXX && Tok != "\"C\"")
+ setError("Unknown language");
+ expect("{");
+
+ std::vector<SymbolVersion> Ret;
+ while (!Error && peek() != "}") {
+ StringRef Tok = next();
+ bool HasWildcard = !Tok.startswith("\"") && hasWildcard(Tok);
+ Ret.push_back({unquote(Tok), IsCXX, HasWildcard});
+ expect(";");
+ }
+
+ expect("}");
+ expect(";");
+ return Ret;
}
-// Entry point.
void elf::readLinkerScript(MemoryBufferRef MB) {
- StringRef Path = MB.getBufferIdentifier();
- ScriptParser(MB.getBuffer(), isUnderSysroot(Path)).run();
+ ScriptParser(MB).readLinkerScript();
+}
+
+void elf::readVersionScript(MemoryBufferRef MB) {
+ ScriptParser(MB).readVersionScript();
+}
+
+void elf::readDynamicList(MemoryBufferRef MB) {
+ ScriptParser(MB).readDynamicList();
}
template class elf::LinkerScript<ELF32LE>;