[llvm-commits] proposed patch to make mips16 exception handling work
Reed Kotler
rkotler at mips.com
Wed Nov 7 21:09:55 PST 2012
Ping..
I have posted some notes on this subject in the llvm developer area.
Probably this patch should be comitted in two pieces, if accepted. The
general change to mcstreamer and dwarf emitter, and the target specific
mips16 piece. The mcstreamer and dwarf emitter part could also be split
in two.
There may be a better way to do this but this works and is reasonably clean.
See discussion of "symbols for exception handling" in the developers list.
The crux of the problem is that the linker adds a 1 to addresses of
mips16 routines.
When you call a function, the ISA determines whether you are in mips16
or mips32 by the presence
or absence of this bit.
Some notes from the gcc mips16 checkins for this explain a lot of the
issues.
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00623.html
http://gcc.gnu.org/ml/gcc-patches/2008-11/msg01273.html
I will add a test case for the mips specific part.
I have post commit review privilege for the mips area but not for any
target independent areas.
he main idea is to distinguish between emitting normal labels and debug
labels. This is the nomenclature chosen by the gcc people working on
this same problem.
I have just added one EmitDebugLabel call, because that is all that is
needed for now to get exceptions to work.
For the general dwarf, the call needs to be made most likely for all
labels apart from the landing pad label.
By default normal and debug labels will be the same.
For Mips, I emit debug labels as:
foo=.
instead of
foo:
I have run "make check", the "test-suite" on x86 and all internal mips
flavors with this patch and no problems arose.
-------------- next part --------------
diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h
index 97aad71..5a23c65 100644
--- a/include/llvm/MC/MCAsmInfo.h
+++ b/include/llvm/MC/MCAsmInfo.h
@@ -102,6 +102,9 @@ namespace llvm {
/// LabelSuffix - This is appended to emitted labels.
const char *LabelSuffix; // Defaults to ":"
+ /// LabelSuffix - This is appended to emitted labels.
+ const char *DebugLabelSuffix; // Defaults to ":"
+
/// GlobalPrefix - If this is set to a non-empty string, it is prepended
/// onto all global symbols. This is often used for "_" or ".".
const char *GlobalPrefix; // Defaults to ""
@@ -426,6 +429,11 @@ namespace llvm {
const char *getLabelSuffix() const {
return LabelSuffix;
}
+
+ const char *getDebugLabelSuffix() const {
+ return DebugLabelSuffix;
+ }
+
const char *getGlobalPrefix() const {
return GlobalPrefix;
}
diff --git a/include/llvm/MC/MCObjectStreamer.h b/include/llvm/MC/MCObjectStreamer.h
index 08b00f1..8e0eae9 100644
--- a/include/llvm/MC/MCObjectStreamer.h
+++ b/include/llvm/MC/MCObjectStreamer.h
@@ -64,6 +64,7 @@ public:
/// @{
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
unsigned AddrSpace);
virtual void EmitULEB128Value(const MCExpr *Value);
diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index 230d27e..c83bf49 100644
--- a/include/llvm/MC/MCStreamer.h
+++ b/include/llvm/MC/MCStreamer.h
@@ -226,6 +226,8 @@ namespace llvm {
/// used in an assignment.
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
+
virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
MCSymbol *EHSymbol);
diff --git a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp b/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
index 4fdd5ca..49e8fa7 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCFIException.cpp
@@ -122,8 +122,9 @@ void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI);
Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
- Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
- Asm->getFunctionNumber()));
+ Asm->OutStreamer.EmitDebugLabel
+ (Asm->GetTempSymbol("eh_func_begin",
+ Asm->getFunctionNumber()));
// Provide LSDA information.
if (!shouldEmitLSDA)
diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index 7ea0f3b..a6fa658 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -37,6 +37,7 @@ MCAsmInfo::MCAsmInfo() {
CommentColumn = 40;
CommentString = "#";
LabelSuffix = ":";
+ DebugLabelSuffix = ":";
GlobalPrefix = "";
PrivateGlobalPrefix = ".";
LinkerPrivateGlobalPrefix = "";
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 17a6323..af5fb0c 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -135,6 +135,8 @@ public:
}
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
+
virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
MCSymbol *EHSymbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
@@ -343,6 +345,14 @@ void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) {
EmitEOL();
}
+void MCAsmStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
+ MCStreamer::EmitDebugLabel(Symbol);
+
+ OS << *Symbol << MAI.getDebugLabelSuffix();
+ EmitEOL();
+}
+
void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
switch (Flag) {
case MCAF_SyntaxUnified: OS << "\t.syntax unified"; break;
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 14fbc1e..0409398 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -56,6 +56,7 @@ public:
virtual void InitSections();
virtual void ChangeSection(const MCSection *Section);
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
virtual void EmitThumbFunc(MCSymbol *Func);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
@@ -169,6 +170,10 @@ void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
MCELF::SetType(SD, ELF::STT_TLS);
}
+void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+}
+
void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
switch (Flag) {
case MCAF_SyntaxUnified: return; // no-op here.
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 04b0e86..5078e83 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -44,6 +44,7 @@ public:
virtual void InitSections();
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
MCSymbol *EHSymbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
@@ -132,6 +133,9 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
SD.setFlags(SD.getFlags() & ~SF_ReferenceTypeMask);
}
+void MCMachOStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+}
void MCMachOStreamer::EmitDataRegion(DataRegionData::KindTy Kind) {
if (!getAssembler().getBackend().hasDataInCodeSupport())
return;
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 4c17d91..76fb5b2 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -36,7 +36,9 @@ namespace {
assert(getCurrentSection() && "Cannot emit before setting section!");
Symbol->setSection(*getCurrentSection());
}
-
+ virtual void EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+ }
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {}
virtual void EmitThumbFunc(MCSymbol *Func) {}
diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index 7746323..f94453a 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -128,6 +128,10 @@ void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
SD.setOffset(F->getContents().size());
}
+void MCObjectStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+}
+
void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
int64_t IntValue;
if (Value->EvaluateAsAbsolute(IntValue, getAssembler())) {
diff --git a/lib/MC/MCPureStreamer.cpp b/lib/MC/MCPureStreamer.cpp
index 9ccab93..eeb849d 100644
--- a/lib/MC/MCPureStreamer.cpp
+++ b/lib/MC/MCPureStreamer.cpp
@@ -37,6 +37,7 @@ public:
virtual void InitSections();
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
uint64_t Size = 0, unsigned ByteAlignment = 0);
@@ -135,6 +136,9 @@ void MCPureStreamer::EmitLabel(MCSymbol *Symbol) {
SD.setOffset(F->getContents().size());
}
+void MCPureStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+}
void MCPureStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
// TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
// MCObjectStreamer.
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index afece0b..120725d 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -181,6 +181,13 @@ void MCStreamer::EmitLabel(MCSymbol *Symbol) {
LastSymbol = Symbol;
}
+void MCStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
+ assert(getCurrentSection() && "Cannot emit before setting section!");
+ Symbol->setSection(*getCurrentSection());
+ LastSymbol = Symbol;
+}
+
void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
EnsureValidFrame();
MCDwarfFrameInfo *CurFrame = getCurrentFrameInfo();
diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index 702eec0..0cfdc58 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -51,6 +51,7 @@ public:
virtual void InitSections();
virtual void EmitLabel(MCSymbol *Symbol);
+ virtual void EmitDebugLabel(MCSymbol *Symbol);
virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
virtual void EmitThumbFunc(MCSymbol *Func);
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
@@ -176,6 +177,9 @@ void WinCOFFStreamer::EmitLabel(MCSymbol *Symbol) {
MCObjectStreamer::EmitLabel(Symbol);
}
+void WinCOFFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+}
void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
llvm_unreachable("not implemented");
}
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
index 9d67aa1..d5ed8b1 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
@@ -34,7 +34,7 @@ MipsMCAsmInfo::MipsMCAsmInfo(const Target &T, StringRef TT) {
GPRel32Directive = "\t.gpword\t";
GPRel64Directive = "\t.gpdword\t";
WeakRefDirective = "\t.weak\t";
-
+ DebugLabelSuffix = "=.";
SupportsDebugInformation = true;
ExceptionsType = ExceptionHandling::DwarfCFI;
HasLEB128 = true;
diff --git a/lib/Target/Mips/Mips16FrameLowering.cpp b/lib/Target/Mips/Mips16FrameLowering.cpp
index 4e6b21f..be4472b 100644
--- a/lib/Target/Mips/Mips16FrameLowering.cpp
+++ b/lib/Target/Mips/Mips16FrameLowering.cpp
@@ -38,10 +38,37 @@ void Mips16FrameLowering::emitPrologue(MachineFunction &MF) const {
// No need to allocate space on the stack.
if (StackSize == 0 && !MFI->adjustsStack()) return;
+ MachineModuleInfo &MMI = MF.getMMI();
+ std::vector<MachineMove> &Moves = MMI.getFrameMoves();
+ MachineLocation DstML, SrcML;
+
// Adjust stack.
if (isInt<16>(-StackSize))
BuildMI(MBB, MBBI, dl, TII.get(Mips::SaveRaF16)).addImm(StackSize);
+ // emit ".cfi_def_cfa_offset StackSize"
+ MCSymbol *AdjustSPLabel = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, dl,
+ TII.get(TargetOpcode::PROLOG_LABEL)).addSym(AdjustSPLabel);
+ DstML = MachineLocation(MachineLocation::VirtualFP);
+ SrcML = MachineLocation(MachineLocation::VirtualFP, -StackSize);
+ Moves.push_back(MachineMove(AdjustSPLabel, DstML, SrcML));
+
+ MCSymbol *CSLabel = MMI.getContext().CreateTempSymbol();
+ BuildMI(MBB, MBBI, dl,
+ TII.get(TargetOpcode::PROLOG_LABEL)).addSym(CSLabel);
+ DstML = MachineLocation(MachineLocation::VirtualFP, -8);
+ SrcML = MachineLocation(Mips::S1);
+ Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
+
+ DstML = MachineLocation(MachineLocation::VirtualFP, -12);
+ SrcML = MachineLocation(Mips::S0);
+ Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
+
+ DstML = MachineLocation(MachineLocation::VirtualFP, -4);
+ SrcML = MachineLocation(Mips::RA);
+ Moves.push_back(MachineMove(CSLabel, DstML, SrcML));
+
if (hasFP(MF))
BuildMI(MBB, MBBI, dl, TII.get(Mips::MoveR3216), Mips::S0)
.addReg(Mips::SP);
diff --git a/tools/lto/LTOModule.cpp b/tools/lto/LTOModule.cpp
index ffdcbe6..cf010f4 100644
--- a/tools/lto/LTOModule.cpp
+++ b/tools/lto/LTOModule.cpp
@@ -743,6 +743,9 @@ namespace {
Symbol->setSection(*getCurrentSection());
markDefined(*Symbol);
}
+ virtual void EmitDebugLabel(MCSymbol *Symbol) {
+ EmitLabel(Symbol);
+ }
virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
// FIXME: should we handle aliases?
markDefined(*Symbol);
More information about the llvm-commits
mailing list