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-rw-r--r--lib/MC/MCDwarf.cpp221
1 files changed, 156 insertions, 65 deletions
diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp
index be6731a..0a3fab8 100644
--- a/lib/MC/MCDwarf.cpp
+++ b/lib/MC/MCDwarf.cpp
@@ -19,6 +19,7 @@
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
@@ -518,8 +519,12 @@ static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
- EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
- EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
+ if (MCOS->getContext().getGenDwarfSectionSyms().size() > 1) {
+ EmitAbbrev(MCOS, dwarf::DW_AT_ranges, dwarf::DW_FORM_data4);
+ } else {
+ EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
+ EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
+ }
EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
if (!context.getCompilationDir().empty())
EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
@@ -552,20 +557,14 @@ static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
}
// When generating dwarf for assembly source files this emits the data for
-// .debug_aranges section. Which contains a header and a table of pairs of
-// PointerSize'ed values for the address and size of section(s) with line table
-// entries (just the default .text in our case) and a terminating pair of zeros.
+// .debug_aranges section. This section contains a header and a table of pairs
+// of PointerSize'ed values for the address and size of section(s) with line
+// table entries.
static void EmitGenDwarfAranges(MCStreamer *MCOS,
const MCSymbol *InfoSectionSymbol) {
MCContext &context = MCOS->getContext();
- // Create a symbol at the end of the section that we are creating the dwarf
- // debugging info to use later in here as part of the expression to calculate
- // the size of the section for the table.
- MCOS->SwitchSection(context.getGenDwarfSection());
- MCSymbol *SectionEndSym = context.CreateTempSymbol();
- MCOS->EmitLabel(SectionEndSym);
- context.setGenDwarfSectionEndSym(SectionEndSym);
+ auto &Sections = context.getGenDwarfSectionSyms();
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
@@ -583,8 +582,8 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
Length += Pad;
// Add the size of the pair of PointerSize'ed values for the address and size
- // of the one default .text section we have in the table.
- Length += 2 * AddrSize;
+ // of each section we have in the table.
+ Length += 2 * AddrSize * Sections.size();
// And the pair of terminating zeros.
Length += 2 * AddrSize;
@@ -608,14 +607,21 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
for(int i = 0; i < Pad; i++)
MCOS->EmitIntValue(0, 1);
- // Now emit the table of pairs of PointerSize'ed values for the section(s)
- // address and size, in our case just the one default .text section.
- const MCExpr *Addr = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
- const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
- *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
- MCOS->EmitValue(Addr, AddrSize);
- MCOS->EmitAbsValue(Size, AddrSize);
+ // Now emit the table of pairs of PointerSize'ed values for the section
+ // addresses and sizes.
+ for (const auto &sec : Sections) {
+ MCSymbol *StartSymbol = sec.second.first;
+ MCSymbol *EndSymbol = sec.second.second;
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ const MCExpr *Addr = MCSymbolRefExpr::Create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
+ *StartSymbol, *EndSymbol, 0);
+ MCOS->EmitValue(Addr, AddrSize);
+ MCOS->EmitAbsValue(Size, AddrSize);
+ }
// And finally the pair of terminating zeros.
MCOS->EmitIntValue(0, AddrSize);
@@ -627,7 +633,8 @@ static void EmitGenDwarfAranges(MCStreamer *MCOS,
// DIE and a list of label DIEs.
static void EmitGenDwarfInfo(MCStreamer *MCOS,
const MCSymbol *AbbrevSectionSymbol,
- const MCSymbol *LineSectionSymbol) {
+ const MCSymbol *LineSectionSymbol,
+ const MCSymbol *RangesSectionSymbol) {
MCContext &context = MCOS->getContext();
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
@@ -674,15 +681,37 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
MCOS->EmitIntValue(0, 4);
}
- // AT_low_pc, the first address of the default .text section.
- const MCExpr *Start = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
- MCOS->EmitValue(Start, AddrSize);
+ if (RangesSectionSymbol) {
+ // There are multiple sections containing code, so we must use the
+ // .debug_ranges sections.
- // AT_high_pc, the last address of the default .text section.
- const MCExpr *End = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
- MCOS->EmitValue(End, AddrSize);
+ // AT_ranges, the 4 byte offset from the start of the .debug_ranges section
+ // to the address range list for this compilation unit.
+ MCOS->EmitSymbolValue(RangesSectionSymbol, 4);
+ } else {
+ // If we only have one non-empty code section, we can use the simpler
+ // AT_low_pc and AT_high_pc attributes.
+
+ // Find the first (and only) non-empty text section
+ auto &Sections = context.getGenDwarfSectionSyms();
+ const auto TextSection = Sections.begin();
+ assert(TextSection != Sections.end() && "No text section found");
+
+ MCSymbol *StartSymbol = TextSection->second.first;
+ MCSymbol *EndSymbol = TextSection->second.second;
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ // AT_low_pc, the first address of the default .text section.
+ const MCExpr *Start = MCSymbolRefExpr::Create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitValue(Start, AddrSize);
+
+ // AT_high_pc, the last address of the default .text section.
+ const MCExpr *End = MCSymbolRefExpr::Create(
+ EndSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitValue(End, AddrSize);
+ }
// AT_name, the name of the source file. Reconstruct from the first directory
// and file table entries.
@@ -766,13 +795,51 @@ static void EmitGenDwarfInfo(MCStreamer *MCOS,
MCOS->EmitLabel(InfoEnd);
}
+// When generating dwarf for assembly source files this emits the data for
+// .debug_ranges section. We only emit one range list, which spans all of the
+// executable sections of this file.
+static void EmitGenDwarfRanges(MCStreamer *MCOS) {
+ MCContext &context = MCOS->getContext();
+ auto &Sections = context.getGenDwarfSectionSyms();
+
+ const MCAsmInfo *AsmInfo = context.getAsmInfo();
+ int AddrSize = AsmInfo->getPointerSize();
+
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+
+ for (const auto sec : Sections) {
+
+ MCSymbol *StartSymbol = sec.second.first;
+ MCSymbol *EndSymbol = sec.second.second;
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ // Emit a base address selection entry for the start of this section
+ const MCExpr *SectionStartAddr = MCSymbolRefExpr::Create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitFill(AddrSize, 0xFF);
+ MCOS->EmitValue(SectionStartAddr, AddrSize);
+
+ // Emit a range list entry spanning this section
+ const MCExpr *SectionSize = MakeStartMinusEndExpr(*MCOS,
+ *StartSymbol, *EndSymbol, 0);
+ MCOS->EmitIntValue(0, AddrSize);
+ MCOS->EmitAbsValue(SectionSize, AddrSize);
+ }
+
+ // Emit end of list entry
+ MCOS->EmitIntValue(0, AddrSize);
+ MCOS->EmitIntValue(0, AddrSize);
+}
+
//
// When generating dwarf for assembly source files this emits the Dwarf
// sections.
//
void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
- // Create the dwarf sections in this order (.debug_line already created).
MCContext &context = MCOS->getContext();
+
+ // Create the dwarf sections in this order (.debug_line already created).
const MCAsmInfo *AsmInfo = context.getAsmInfo();
bool CreateDwarfSectionSymbols =
AsmInfo->doesDwarfUseRelocationsAcrossSections();
@@ -781,6 +848,22 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
LineSectionSymbol = MCOS->getDwarfLineTableSymbol(0);
MCSymbol *AbbrevSectionSymbol = nullptr;
MCSymbol *InfoSectionSymbol = nullptr;
+ MCSymbol *RangesSectionSymbol = NULL;
+
+ // Create end symbols for each section, and remove empty sections
+ MCOS->getContext().finalizeDwarfSections(*MCOS);
+
+ // If there are no sections to generate debug info for, we don't need
+ // to do anything
+ if (MCOS->getContext().getGenDwarfSectionSyms().empty())
+ return;
+
+ // We only need to use the .debug_ranges section if we have multiple
+ // code sections.
+ const bool UseRangesSection =
+ MCOS->getContext().getGenDwarfSectionSyms().size() > 1;
+ CreateDwarfSectionSymbols |= UseRangesSection;
+
MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
if (CreateDwarfSectionSymbols) {
InfoSectionSymbol = context.CreateTempSymbol();
@@ -791,20 +874,30 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
AbbrevSectionSymbol = context.CreateTempSymbol();
MCOS->EmitLabel(AbbrevSectionSymbol);
}
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
+ if (UseRangesSection) {
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+ if (CreateDwarfSectionSymbols) {
+ RangesSectionSymbol = context.CreateTempSymbol();
+ MCOS->EmitLabel(RangesSectionSymbol);
+ }
+ }
- // If there are no line table entries then do not emit any section contents.
- if (!context.hasMCLineSections())
- return;
+ assert((RangesSectionSymbol != NULL) || !UseRangesSection);
+
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
// Output the data for .debug_aranges section.
EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
+ if (UseRangesSection)
+ EmitGenDwarfRanges(MCOS);
+
// Output the data for .debug_abbrev section.
EmitGenDwarfAbbrev(MCOS);
// Output the data for .debug_info section.
- EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
+ EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol,
+ RangesSectionSymbol);
}
//
@@ -815,12 +908,13 @@ void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
//
void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
SourceMgr &SrcMgr, SMLoc &Loc) {
- // We won't create dwarf labels for temporary symbols or symbols not in
- // the default text.
+ // We won't create dwarf labels for temporary symbols.
if (Symbol->isTemporary())
return;
MCContext &context = MCOS->getContext();
- if (context.getGenDwarfSection() != MCOS->getCurrentSection().first)
+ // We won't create dwarf labels for symbols in sections that we are not
+ // generating debug info for.
+ if (!context.getGenDwarfSectionSyms().count(MCOS->getCurrentSection().first))
return;
// The dwarf label's name does not have the symbol name's leading
@@ -834,7 +928,7 @@ void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
// Finding the line number is the expensive part which is why we just don't
// pass it in as for some symbols we won't create a dwarf label.
- int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
+ unsigned CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
// We create a temporary symbol for use for the AT_high_pc and AT_low_pc
@@ -1203,7 +1297,7 @@ void FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
unsigned FDEEncoding = MOFI->getFDEEncoding();
unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
if (VerboseAsm) Streamer.AddComment("Range Start");
- Streamer.EmitSymbolValue(Frame.Function, Size);
+ Streamer.EmitSymbolValue(Frame.Begin, Size);
// Range Length
const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
@@ -1246,12 +1340,7 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
bool verboseAsm = streamer.isVerboseAsm();
- MCSymbol *sectionStart;
- if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
- sectionStart = context.CreateTempSymbol();
- else
- sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
-
+ MCSymbol *sectionStart = context.CreateTempSymbol();
streamer.EmitLabel(sectionStart);
CIENum++;
@@ -1270,7 +1359,10 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
// Version
if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
- streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
+ // For DWARF2, we use CIE version 1
+ // For DWARF3+, we use CIE version 3
+ uint8_t CIEVersion = context.getDwarfVersion() <= 2 ? 1 : 3;
+ streamer.EmitIntValue(CIEVersion, 1);
// Augmentation String
SmallString<8> Augmentation;
@@ -1298,7 +1390,14 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
// Return Address Register
if (verboseAsm) streamer.AddComment("CIE Return Address Column");
- streamer.EmitULEB128IntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true));
+ if (CIEVersion == 1) {
+ assert(MRI->getRARegister() <= 255 &&
+ "DWARF 2 encodes return_address_register in one byte");
+ streamer.EmitIntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true), 1);
+ } else {
+ streamer.EmitULEB128IntValue(
+ MRI->getDwarfRegNum(MRI->getRARegister(), true));
+ }
// Augmentation Data Length (optional)
@@ -1360,13 +1459,6 @@ MCSymbol *FrameEmitterImpl::EmitFDE(MCObjectStreamer &streamer,
const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
bool verboseAsm = streamer.isVerboseAsm();
- if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
- MCSymbol *EHSym =
- context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
- streamer.EmitEHSymAttributes(frame.Function, EHSym);
- streamer.EmitLabel(EHSym);
- }
-
// Length
const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
if (verboseAsm) streamer.AddComment("FDE Length");
@@ -1435,13 +1527,12 @@ namespace {
return CIEKey(nullptr, -1, 0, false, false);
}
- CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
- unsigned LsdaEncoding_, bool IsSignalFrame_, bool IsSimple_) :
- Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
- LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_),
- IsSimple(IsSimple_) {
- }
- const MCSymbol* Personality;
+ CIEKey(const MCSymbol *Personality_, unsigned PersonalityEncoding_,
+ unsigned LsdaEncoding_, bool IsSignalFrame_, bool IsSimple_)
+ : Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
+ LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_),
+ IsSimple(IsSimple_) {}
+ const MCSymbol *Personality;
unsigned PersonalityEncoding;
unsigned LsdaEncoding;
bool IsSignalFrame;
@@ -1516,7 +1607,7 @@ void MCDwarfFrameEmitter::Emit(MCObjectStreamer &Streamer, MCAsmBackend *MAB,
Emitter.setSectionStart(SectionStart);
MCSymbol *FDEEnd = nullptr;
- DenseMap<CIEKey, const MCSymbol*> CIEStarts;
+ DenseMap<CIEKey, const MCSymbol *> CIEStarts;
const MCSymbol *DummyDebugKey = nullptr;
NeedsEHFrameSection = !MOFI->getSupportsCompactUnwindWithoutEHFrame();
generated by cgit v1.1 at 2024-12-22 14:23:11 +0000