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-rw-r--r--ELF/OutputSections.cpp42
1 files changed, 42 insertions, 0 deletions
diff --git a/ELF/OutputSections.cpp b/ELF/OutputSections.cpp
index 93f83100a745..a40818d2d301 100644
--- a/ELF/OutputSections.cpp
+++ b/ELF/OutputSections.cpp
@@ -16,6 +16,7 @@
#include "SyntheticSections.h"
#include "Target.h"
#include "Threads.h"
+#include "llvm/Support/Compression.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"
@@ -83,6 +84,33 @@ static bool compareByFilePosition(InputSection *A, InputSection *B) {
return LA->OutSecOff < LB->OutSecOff;
}
+// Compress section contents if this section contains debug info.
+template <class ELFT> void OutputSection::maybeCompress() {
+ typedef typename ELFT::Chdr Elf_Chdr;
+
+ // Compress only DWARF debug sections.
+ if (!Config->CompressDebugSections || (Flags & SHF_ALLOC) ||
+ !Name.startswith(".debug_"))
+ return;
+
+ // Create a section header.
+ ZDebugHeader.resize(sizeof(Elf_Chdr));
+ auto *Hdr = reinterpret_cast<Elf_Chdr *>(ZDebugHeader.data());
+ Hdr->ch_type = ELFCOMPRESS_ZLIB;
+ Hdr->ch_size = Size;
+ Hdr->ch_addralign = Alignment;
+
+ // Write section contents to a temporary buffer and compress it.
+ std::vector<uint8_t> Buf(Size);
+ writeTo<ELFT>(Buf.data());
+ if (Error E = zlib::compress(toStringRef(Buf), CompressedData))
+ fatal("compress failed: " + llvm::toString(std::move(E)));
+
+ // Update section headers.
+ Size = sizeof(Elf_Chdr) + CompressedData.size();
+ Flags |= SHF_COMPRESSED;
+}
+
template <class ELFT> void OutputSection::finalize() {
if ((this->Flags & SHF_LINK_ORDER) && !this->Sections.empty()) {
std::sort(Sections.begin(), Sections.end(), compareByFilePosition);
@@ -245,6 +273,15 @@ uint32_t OutputSection::getFiller() {
template <class ELFT> void OutputSection::writeTo(uint8_t *Buf) {
Loc = Buf;
+ // We may have already rendered compressed content when using
+ // -compress-debug-sections option. Write it together with header.
+ if (!CompressedData.empty()) {
+ memcpy(Buf, ZDebugHeader.data(), ZDebugHeader.size());
+ memcpy(Buf + ZDebugHeader.size(), CompressedData.data(),
+ CompressedData.size());
+ return;
+ }
+
// Write leading padding.
uint32_t Filler = getFiller();
if (Filler)
@@ -422,6 +459,11 @@ template void OutputSection::finalize<ELF32BE>();
template void OutputSection::finalize<ELF64LE>();
template void OutputSection::finalize<ELF64BE>();
+template void OutputSection::maybeCompress<ELF32LE>();
+template void OutputSection::maybeCompress<ELF32BE>();
+template void OutputSection::maybeCompress<ELF64LE>();
+template void OutputSection::maybeCompress<ELF64BE>();
+
template void OutputSection::writeTo<ELF32LE>(uint8_t *Buf);
template void OutputSection::writeTo<ELF32BE>(uint8_t *Buf);
template void OutputSection::writeTo<ELF64LE>(uint8_t *Buf);