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Fix PR21189 -- Emit symbol subsection required to debug LLVM-built binaries with VS2012+

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Reviewed at http://reviews.llvm.org/D5772

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220544 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Timur Iskhodzhanov
2014-10-24 01:27:45 +00:00
parent 8a5eafb58d
commit 92e132a36f
5 changed files with 493 additions and 35 deletions
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56
lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
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@ -168,14 +168,15 @@ void WinCodeViewLineTables::endModule() {
}
static void EmitLabelDiff(MCStreamer &Streamer,
const MCSymbol *From, const MCSymbol *To) {
const MCSymbol *From, const MCSymbol *To,
unsigned int Size = 4) {
MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
MCContext &Context = Streamer.getContext();
const MCExpr *FromRef = MCSymbolRefExpr::Create(From, Variant, Context),
*ToRef = MCSymbolRefExpr::Create(To, Variant, Context);
const MCExpr *AddrDelta =
MCBinaryExpr::Create(MCBinaryExpr::Sub, ToRef, FromRef, Context);
Streamer.EmitValue(AddrDelta, 4);
Streamer.EmitValue(AddrDelta, Size);
}
void WinCodeViewLineTables::emitDebugInfoForFunction(const Function *GV) {
@ -189,6 +190,44 @@ void WinCodeViewLineTables::emitDebugInfoForFunction(const Function *GV) {
return;
assert(FI.End && "Don't know where the function ends?");
const StringRef FuncName = getDISubprogram(GV).getDisplayName();
// Emit a symbol subsection, required by VS2012+ to find function boundaries.
MCSymbol *SymbolsBegin = Asm->MMI->getContext().CreateTempSymbol(),
*SymbolsEnd = Asm->MMI->getContext().CreateTempSymbol();
Asm->OutStreamer.AddComment("Symbol subsection for " + Twine(FuncName));
Asm->EmitInt32(COFF::DEBUG_SYMBOL_SUBSECTION);
EmitLabelDiff(Asm->OutStreamer, SymbolsBegin, SymbolsEnd);
Asm->OutStreamer.EmitLabel(SymbolsBegin);
{
MCSymbol *ProcSegmentBegin = Asm->MMI->getContext().CreateTempSymbol(),
*ProcSegmentEnd = Asm->MMI->getContext().CreateTempSymbol();
EmitLabelDiff(Asm->OutStreamer, ProcSegmentBegin, ProcSegmentEnd, 2);
Asm->OutStreamer.EmitLabel(ProcSegmentBegin);
Asm->EmitInt16(COFF::DEBUG_SYMBOL_TYPE_PROC_START);
// Some bytes of this segment don't seem to be required for basic debugging,
// so just fill them with zeroes.
Asm->OutStreamer.EmitFill(12, 0);
// This is the important bit that tells the debugger where the function
// code is located and what's its size:
EmitLabelDiff(Asm->OutStreamer, Fn, FI.End);
Asm->OutStreamer.EmitFill(12, 0);
Asm->OutStreamer.EmitCOFFSecRel32(Fn);
Asm->OutStreamer.EmitCOFFSectionIndex(Fn);
Asm->EmitInt8(0);
// Emit the function name as a null-terminated string.
Asm->OutStreamer.EmitBytes(FuncName);
Asm->EmitInt8(0);
Asm->OutStreamer.EmitLabel(ProcSegmentEnd);
// We're done with this function.
Asm->EmitInt16(0x0002);
Asm->EmitInt16(COFF::DEBUG_SYMBOL_TYPE_PROC_END);
}
Asm->OutStreamer.EmitLabel(SymbolsEnd);
// Every subsection must be aligned to a 4-byte boundary.
Asm->OutStreamer.EmitFill((-FuncName.size()) % 4, 0);
// PCs/Instructions are grouped into segments sharing the same filename.
// Pre-calculate the lengths (in instructions) of these segments and store
// them in a map for convenience. Each index in the map is the sequential
@ -206,13 +245,12 @@ void WinCodeViewLineTables::emitDebugInfoForFunction(const Function *GV) {
FilenameSegmentLengths[LastSegmentEnd] = FI.Instrs.size() - LastSegmentEnd;
// Emit a line table subsection, requred to do PC-to-file:line lookup.
Asm->OutStreamer.AddComment(
"Line table subsection for " + Twine(Fn->getName()));
Asm->OutStreamer.AddComment("Line table subsection for " + Twine(FuncName));
Asm->EmitInt32(COFF::DEBUG_LINE_TABLE_SUBSECTION);
MCSymbol *SubsectionBegin = Asm->MMI->getContext().CreateTempSymbol(),
*SubsectionEnd = Asm->MMI->getContext().CreateTempSymbol();
EmitLabelDiff(Asm->OutStreamer, SubsectionBegin, SubsectionEnd);
Asm->OutStreamer.EmitLabel(SubsectionBegin);
MCSymbol *LineTableBegin = Asm->MMI->getContext().CreateTempSymbol(),
*LineTableEnd = Asm->MMI->getContext().CreateTempSymbol();
EmitLabelDiff(Asm->OutStreamer, LineTableBegin, LineTableEnd);
Asm->OutStreamer.EmitLabel(LineTableBegin);
// Identify the function this subsection is for.
Asm->OutStreamer.EmitCOFFSecRel32(Fn);
@ -262,7 +300,7 @@ void WinCodeViewLineTables::emitDebugInfoForFunction(const Function *GV) {
if (FileSegmentEnd)
Asm->OutStreamer.EmitLabel(FileSegmentEnd);
Asm->OutStreamer.EmitLabel(SubsectionEnd);
Asm->OutStreamer.EmitLabel(LineTableEnd);
}
void WinCodeViewLineTables::beginFunction(const MachineFunction *MF) {