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Preliminary patch to improve dwarf EH generation - Hooks to return Personality / FDE / LSDA / TType encoding depending on target / options (e.g. code model / relocation model) - MCIzation of Dwarf EH printer to use encoding information - Stub generation for ELF target (needed for indirect references) - Some other small changes here and there

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96285 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov
2010-02-15 22:35:59 +00:00
parent 6a7cb63f6f
commit 9184b25fa5
20 changed files with 470 additions and 297 deletions
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120
lib/CodeGen/AsmPrinter/DwarfException.cpp
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@@ -50,26 +50,6 @@ DwarfException::~DwarfException() {
delete ExceptionTimer;
}
/// SizeOfEncodedValue - Return the size of the encoding in bytes.
unsigned DwarfException::SizeOfEncodedValue(unsigned Encoding) {
if (Encoding == dwarf::DW_EH_PE_omit)
return 0;
switch (Encoding & 0x07) {
case dwarf::DW_EH_PE_absptr:
return TD->getPointerSize();
case dwarf::DW_EH_PE_udata2:
return 2;
case dwarf::DW_EH_PE_udata4:
return 4;
case dwarf::DW_EH_PE_udata8:
return 8;
}
assert(0 && "Invalid encoded value.");
return 0;
}
/// CreateLabelDiff - Emit a label and subtract it from the expression we
/// already have. This is equivalent to emitting "foo - .", but we have to emit
/// the label for "." directly.
@@ -100,7 +80,7 @@ void DwarfException::EmitCIE(const Function *PersonalityFn, unsigned Index) {
TD->getPointerSize() : -TD->getPointerSize();
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
// Begin eh frame section.
Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
@@ -128,30 +108,16 @@ void DwarfException::EmitCIE(const Function *PersonalityFn, unsigned Index) {
// The personality presence indicates that language specific information will
// show up in the eh frame. Find out how we are supposed to lower the
// personality function reference:
const MCExpr *PersonalityRef = 0;
bool IsPersonalityIndirect = false, IsPersonalityPCRel = false;
if (PersonalityFn) {
// FIXME: HANDLE STATIC CODEGEN MODEL HERE.
// In non-static mode, ask the object file how to represent this reference.
PersonalityRef =
TLOF.getSymbolForDwarfGlobalReference(PersonalityFn, Asm->Mang,
Asm->MMI,
IsPersonalityIndirect,
IsPersonalityPCRel);
}
unsigned PerEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
if (IsPersonalityIndirect)
PerEncoding |= dwarf::DW_EH_PE_indirect;
unsigned LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
unsigned FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
unsigned FDEEncoding = TLOF.getFDEEncoding();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
char Augmentation[6] = { 0 };
unsigned AugmentationSize = 0;
char *APtr = Augmentation + 1;
if (PersonalityRef) {
if (PersonalityFn) {
// There is a personality function.
*APtr++ = 'P';
AugmentationSize += 1 + SizeOfEncodedValue(PerEncoding);
@@ -182,19 +148,16 @@ void DwarfException::EmitCIE(const Function *PersonalityFn, unsigned Index) {
EOL("CIE Return Address Column");
EmitULEB128(AugmentationSize, "Augmentation Size");
EmitEncodingByte(PerEncoding, "Personality");
// If there is a personality, we need to indicate the function's location.
if (PersonalityRef) {
if (!IsPersonalityPCRel)
PersonalityRef = CreateLabelDiff(PersonalityRef, "personalityref_addr",
Index);
O << MAI->getData32bitsDirective() << *PersonalityRef;
if (PersonalityFn) {
EmitEncodingByte(PerEncoding, "Personality");
EmitReference(PersonalityFn, PerEncoding);
EOL("Personality");
EmitEncodingByte(LSDAEncoding, "LSDA");
EmitEncodingByte(FDEEncoding, "FDE");
if (UsesLSDA[Index])
EmitEncodingByte(LSDAEncoding, "LSDA");
if (FDEEncoding != dwarf::DW_EH_PE_absptr)
EmitEncodingByte(FDEEncoding, "FDE");
}
// Indicate locations of general callee saved registers in frame.
@@ -216,8 +179,12 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
"Should not emit 'available externally' functions at all");
const Function *TheFunc = EHFrameInfo.function;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering().getEHFrameSection());
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
unsigned FDEEncoding = TLOF.getFDEEncoding();
Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
// Externally visible entry into the functions eh frame info. If the
// corresponding function is static, this should not be externally visible.
@@ -255,7 +222,8 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
// EH frame header.
EmitDifference("eh_frame_end", EHFrameInfo.Number,
"eh_frame_begin", EHFrameInfo.Number, true);
"eh_frame_begin", EHFrameInfo.Number,
true);
EOL("Length of Frame Information Entry");
EmitLabel("eh_frame_begin", EHFrameInfo.Number);
@@ -266,33 +234,23 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
EOL("FDE CIE offset");
EmitReference("eh_func_begin", EHFrameInfo.Number, true, true);
EmitReference("eh_func_begin", EHFrameInfo.Number, FDEEncoding);
EOL("FDE initial location");
EmitDifference("eh_func_end", EHFrameInfo.Number,
"eh_func_begin", EHFrameInfo.Number, true);
"eh_func_begin", EHFrameInfo.Number,
SizeOfEncodedValue(FDEEncoding) == 4);
EOL("FDE address range");
// If there is a personality and landing pads then point to the language
// specific data area in the exception table.
if (MMI->getPersonalities()[0] != NULL) {
unsigned Size = SizeOfEncodedValue(LSDAEncoding);
if (Asm->TM.getLSDAEncoding() != DwarfLSDAEncoding::EightByte) {
EmitULEB128(4, "Augmentation size");
if (EHFrameInfo.hasLandingPads)
EmitReference("exception", EHFrameInfo.Number, true, true);
else
Asm->OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
} else {
EmitULEB128(TD->getPointerSize(), "Augmentation size");
if (EHFrameInfo.hasLandingPads) {
EmitReference("exception", EHFrameInfo.Number, true, false);
} else {
Asm->OutStreamer.EmitIntValue(0, TD->getPointerSize(),
0/*addrspace*/);
}
}
EmitULEB128(Size, "Augmentation size");
if (EHFrameInfo.hasLandingPads)
EmitReference("exception", EHFrameInfo.Number, LSDAEncoding);
else
Asm->OutStreamer.EmitIntValue(0, Size/*size*/, 0/*addrspace*/);
EOL("Language Specific Data Area");
} else {
@@ -694,13 +652,13 @@ void DwarfException::EmitExceptionTable() {
// Type infos.
const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
unsigned TTypeFormat;
unsigned TTypeEncoding;
unsigned TypeFormatSize;
if (!HaveTTData) {
// For SjLj exceptions, if there is no TypeInfo, then we just explicitly say
// that we're omitting that bit.
TTypeFormat = dwarf::DW_EH_PE_omit;
TTypeEncoding = dwarf::DW_EH_PE_omit;
TypeFormatSize = SizeOfEncodedValue(dwarf::DW_EH_PE_absptr);
} else {
// Okay, we have actual filters or typeinfos to emit. As such, we need to
@@ -730,14 +688,8 @@ void DwarfException::EmitExceptionTable() {
// somewhere. This predicate should be moved to a shared location that is
// in target-independent code.
//
if (LSDASection->getKind().isWriteable() ||
Asm->TM.getRelocationModel() == Reloc::Static)
TTypeFormat = dwarf::DW_EH_PE_absptr;
else
TTypeFormat = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
dwarf::DW_EH_PE_sdata4;
TypeFormatSize = SizeOfEncodedValue(TTypeFormat);
TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
TypeFormatSize = SizeOfEncodedValue(TTypeEncoding);
}
// Begin the exception table.
@@ -788,7 +740,7 @@ void DwarfException::EmitExceptionTable() {
// Emit the header.
EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
EmitEncodingByte(TTypeFormat, "@TType");
EmitEncodingByte(TTypeEncoding, "@TType");
if (HaveTTData)
EmitULEB128(TyOffset, "@TType base offset");
@@ -911,12 +863,12 @@ void DwarfException::EmitExceptionTable() {
for (std::vector<GlobalVariable *>::const_reverse_iterator
I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
const GlobalVariable *GV = *I;
PrintRelDirective();
if (GV) {
O << *Asm->GetGlobalValueSymbol(GV);
EmitReference(GV, TTypeEncoding);
EOL("TypeInfo");
} else {
PrintRelDirective();
O << "0x0";
EOL("");
}