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-rw-r--r--ELF/LinkerScript.h275
1 files changed, 235 insertions, 40 deletions
diff --git a/ELF/LinkerScript.h b/ELF/LinkerScript.h
index 768f78a66468..505162f0ab43 100644
--- a/ELF/LinkerScript.h
+++ b/ELF/LinkerScript.h
@@ -10,86 +10,279 @@
#ifndef LLD_ELF_LINKER_SCRIPT_H
#define LLD_ELF_LINKER_SCRIPT_H
+#include "Config.h"
+#include "Strings.h"
+#include "Writer.h"
#include "lld/Core/LLVM.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/MapVector.h"
-#include "llvm/Support/Allocator.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/StringRef.h"
#include "llvm/Support/MemoryBuffer.h"
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <vector>
namespace lld {
namespace elf {
+class DefinedCommon;
+class ScriptParser;
+class SymbolBody;
+template <class ELFT> class InputSectionBase;
+template <class ELFT> class InputSection;
+class OutputSectionBase;
+template <class ELFT> class OutputSectionFactory;
+class InputSectionData;
+
+// This represents an expression in the linker script.
+// ScriptParser::readExpr reads an expression and returns an Expr.
+// Later, we evaluate the expression by calling the function
+// with the value of special context variable ".".
+struct Expr {
+ std::function<uint64_t(uint64_t)> Val;
+ std::function<bool()> IsAbsolute;
+
+ // If expression is section-relative the function below is used
+ // to get the output section pointer.
+ std::function<const OutputSectionBase *()> Section;
+
+ uint64_t operator()(uint64_t Dot) const { return Val(Dot); }
+ operator bool() const { return (bool)Val; }
+
+ Expr(std::function<uint64_t(uint64_t)> Val, std::function<bool()> IsAbsolute,
+ std::function<const OutputSectionBase *()> Section)
+ : Val(Val), IsAbsolute(IsAbsolute), Section(Section) {}
+ template <typename T>
+ Expr(T V) : Expr(V, [] { return true; }, [] { return nullptr; }) {}
+ Expr() : Expr(nullptr) {}
+};
+
// Parses a linker script. Calling this function updates
// Config and ScriptConfig.
void readLinkerScript(MemoryBufferRef MB);
-class ScriptParser;
-template <class ELFT> class InputSectionBase;
-template <class ELFT> class OutputSectionBase;
+// Parses a version script.
+void readVersionScript(MemoryBufferRef MB);
+
+void readDynamicList(MemoryBufferRef MB);
+
+// This enum is used to implement linker script SECTIONS command.
+// https://sourceware.org/binutils/docs/ld/SECTIONS.html#SECTIONS
+enum SectionsCommandKind {
+ AssignmentKind, // . = expr or <sym> = expr
+ OutputSectionKind,
+ InputSectionKind,
+ AssertKind, // ASSERT(expr)
+ BytesDataKind // BYTE(expr), SHORT(expr), LONG(expr) or QUAD(expr)
+};
+
+struct BaseCommand {
+ BaseCommand(int K) : Kind(K) {}
+
+ virtual ~BaseCommand() = default;
-// This class represents each rule in SECTIONS command.
-struct SectionRule {
- SectionRule(StringRef D, StringRef S)
- : Dest(D), SectionPattern(S) {}
+ int Kind;
+};
+
+// This represents ". = <expr>" or "<symbol> = <expr>".
+struct SymbolAssignment : BaseCommand {
+ SymbolAssignment(StringRef Name, Expr E)
+ : BaseCommand(AssignmentKind), Name(Name), Expression(E) {}
+
+ static bool classof(const BaseCommand *C);
+
+ // The LHS of an expression. Name is either a symbol name or ".".
+ StringRef Name;
+ SymbolBody *Sym = nullptr;
- StringRef Dest;
+ // The RHS of an expression.
+ Expr Expression;
- StringRef SectionPattern;
+ // Command attributes for PROVIDE, HIDDEN and PROVIDE_HIDDEN.
+ bool Provide = false;
+ bool Hidden = false;
};
-// This enum represents what we can observe in SECTIONS tag of script:
-// ExprKind is a location counter change, like ". = . + 0x1000"
-// SectionKind is a description of output section, like ".data :..."
-enum SectionsCommandKind { SectionKind, AssignmentKind };
+// Linker scripts allow additional constraints to be put on ouput sections.
+// If an output section is marked as ONLY_IF_RO, the section is created
+// only if its input sections are read-only. Likewise, an output section
+// with ONLY_IF_RW is created if all input sections are RW.
+enum class ConstraintKind { NoConstraint, ReadOnly, ReadWrite };
+
+struct OutputSectionCommand : BaseCommand {
+ OutputSectionCommand(StringRef Name)
+ : BaseCommand(OutputSectionKind), Name(Name) {}
+
+ static bool classof(const BaseCommand *C);
-struct SectionsCommand {
- SectionsCommandKind Kind;
- std::vector<StringRef> Expr;
StringRef Name;
+ Expr AddrExpr;
+ Expr AlignExpr;
+ Expr LMAExpr;
+ Expr SubalignExpr;
+ std::vector<std::unique_ptr<BaseCommand>> Commands;
+ std::vector<StringRef> Phdrs;
+ uint32_t Filler = 0;
+ ConstraintKind Constraint = ConstraintKind::NoConstraint;
+ std::string Location;
};
-// ScriptConfiguration holds linker script parse results.
-struct ScriptConfiguration {
- // SECTIONS commands.
- std::vector<SectionRule> Sections;
+// This struct represents one section match pattern in SECTIONS() command.
+// It can optionally have negative match pattern for EXCLUDED_FILE command.
+// Also it may be surrounded with SORT() command, so contains sorting rules.
+struct SectionPattern {
+ SectionPattern(StringMatcher &&Pat1, StringMatcher &&Pat2)
+ : ExcludedFilePat(Pat1), SectionPat(Pat2) {}
+
+ StringMatcher ExcludedFilePat;
+ StringMatcher SectionPat;
+ SortSectionPolicy SortOuter;
+ SortSectionPolicy SortInner;
+};
+
+struct InputSectionDescription : BaseCommand {
+ InputSectionDescription(StringRef FilePattern)
+ : BaseCommand(InputSectionKind), FilePat(FilePattern) {}
- // Section fill attribute for each section.
- llvm::StringMap<std::vector<uint8_t>> Filler;
+ static bool classof(const BaseCommand *C);
+ StringMatcher FilePat;
+
+ // Input sections that matches at least one of SectionPatterns
+ // will be associated with this InputSectionDescription.
+ std::vector<SectionPattern> SectionPatterns;
+
+ std::vector<InputSectionData *> Sections;
+};
+
+// Represents an ASSERT().
+struct AssertCommand : BaseCommand {
+ AssertCommand(Expr E) : BaseCommand(AssertKind), Expression(E) {}
+
+ static bool classof(const BaseCommand *C);
+
+ Expr Expression;
+};
+
+// Represents BYTE(), SHORT(), LONG(), or QUAD().
+struct BytesDataCommand : BaseCommand {
+ BytesDataCommand(Expr E, unsigned Size)
+ : BaseCommand(BytesDataKind), Expression(E), Size(Size) {}
+
+ static bool classof(const BaseCommand *C);
+
+ Expr Expression;
+ unsigned Offset;
+ unsigned Size;
+};
+
+struct PhdrsCommand {
+ StringRef Name;
+ unsigned Type;
+ bool HasFilehdr;
+ bool HasPhdrs;
+ unsigned Flags;
+ Expr LMAExpr;
+};
+
+class LinkerScriptBase {
+protected:
+ ~LinkerScriptBase() = default;
+
+public:
+ virtual uint64_t getHeaderSize() = 0;
+ virtual uint64_t getSymbolValue(const Twine &Loc, StringRef S) = 0;
+ virtual bool isDefined(StringRef S) = 0;
+ virtual bool isAbsolute(StringRef S) = 0;
+ virtual const OutputSectionBase *getSymbolSection(StringRef S) = 0;
+ virtual const OutputSectionBase *getOutputSection(const Twine &Loc,
+ StringRef S) = 0;
+ virtual uint64_t getOutputSectionSize(StringRef S) = 0;
+};
+
+// ScriptConfiguration holds linker script parse results.
+struct ScriptConfiguration {
// Used to assign addresses to sections.
- std::vector<SectionsCommand> Commands;
+ std::vector<std::unique_ptr<BaseCommand>> Commands;
- bool DoLayout = false;
+ // Used to assign sections to headers.
+ std::vector<PhdrsCommand> PhdrsCommands;
- llvm::BumpPtrAllocator Alloc;
+ bool HasSections = false;
// List of section patterns specified with KEEP commands. They will
// be kept even if they are unused and --gc-sections is specified.
- std::vector<StringRef> KeptSections;
+ std::vector<InputSectionDescription *> KeptSections;
};
extern ScriptConfiguration *ScriptConfig;
// This is a runner of the linker script.
-template <class ELFT> class LinkerScript {
+template <class ELFT> class LinkerScript final : public LinkerScriptBase {
typedef typename ELFT::uint uintX_t;
public:
- StringRef getOutputSection(InputSectionBase<ELFT> *S);
- ArrayRef<uint8_t> getFiller(StringRef Name);
- bool isDiscarded(InputSectionBase<ELFT> *S);
+ LinkerScript();
+ ~LinkerScript();
+
+ void processCommands(OutputSectionFactory<ELFT> &Factory);
+ void addOrphanSections(OutputSectionFactory<ELFT> &Factory);
+ void removeEmptyCommands();
+ void adjustSectionsBeforeSorting();
+ void adjustSectionsAfterSorting();
+
+ std::vector<PhdrEntry> createPhdrs();
+ bool ignoreInterpSection();
+
+ uint32_t getFiller(StringRef Name);
+ void writeDataBytes(StringRef Name, uint8_t *Buf);
+ bool hasLMA(StringRef Name);
bool shouldKeep(InputSectionBase<ELFT> *S);
- void assignAddresses(ArrayRef<OutputSectionBase<ELFT> *> S);
- int compareSections(StringRef A, StringRef B);
- void addScriptedSymbols();
+ void assignOffsets(OutputSectionCommand *Cmd);
+ void placeOrphanSections();
+ void assignAddresses(std::vector<PhdrEntry> &Phdrs);
+ bool hasPhdrsCommands();
+ uint64_t getHeaderSize() override;
+ uint64_t getSymbolValue(const Twine &Loc, StringRef S) override;
+ bool isDefined(StringRef S) override;
+ bool isAbsolute(StringRef S) override;
+ const OutputSectionBase *getSymbolSection(StringRef S) override;
+ const OutputSectionBase *getOutputSection(const Twine &Loc,
+ StringRef S) override;
+ uint64_t getOutputSectionSize(StringRef S) override;
+
+ std::vector<OutputSectionBase *> *OutputSections;
+
+ int getSectionIndex(StringRef Name);
private:
+ void computeInputSections(InputSectionDescription *);
+
+ void addSection(OutputSectionFactory<ELFT> &Factory,
+ InputSectionBase<ELFT> *Sec, StringRef Name);
+ void discard(ArrayRef<InputSectionBase<ELFT> *> V);
+
+ std::vector<InputSectionBase<ELFT> *>
+ createInputSectionList(OutputSectionCommand &Cmd);
+
// "ScriptConfig" is a bit too long, so define a short name for it.
ScriptConfiguration &Opt = *ScriptConfig;
- int getSectionIndex(StringRef Name);
+ std::vector<size_t> getPhdrIndices(StringRef SectionName);
+ size_t getPhdrIndex(const Twine &Loc, StringRef PhdrName);
uintX_t Dot;
+ uintX_t LMAOffset = 0;
+ OutputSectionBase *CurOutSec = nullptr;
+ uintX_t ThreadBssOffset = 0;
+ void switchTo(OutputSectionBase *Sec);
+ void flush();
+ void output(InputSection<ELFT> *Sec);
+ void process(BaseCommand &Base);
+ llvm::DenseSet<OutputSectionBase *> AlreadyOutputOS;
+ llvm::DenseSet<InputSectionData *> AlreadyOutputIS;
};
// Variable template is a C++14 feature, so we can't template
@@ -97,7 +290,9 @@ private:
template <class ELFT> struct Script { static LinkerScript<ELFT> *X; };
template <class ELFT> LinkerScript<ELFT> *Script<ELFT>::X;
-} // namespace elf
-} // namespace lld
+extern LinkerScriptBase *ScriptBase;
+
+} // end namespace elf
+} // end namespace lld
-#endif
+#endif // LLD_ELF_LINKER_SCRIPT_H