From 9215947c83860d17bcff19ab4070b6344d28149c Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Sat, 4 Dec 2010 03:21:47 +0000 Subject: [PATCH] There are two reasons why we might want to use foo = a - b .long foo instead of just .long a - b First, on darwin9 64 bits the assembler produces the wrong result. Second, if "a" is the end of the section all darwin assemblers (9, 10 and mc) will not consider a - b to be a constant but will if the dummy foo is created. Split how we handle these cases. The first one is something MC should take care of. The second one has to be handled by the caller. llvm-svn: 120889 --- include/llvm/MC/MCAsmInfo.h | 8 +++++++ include/llvm/MC/MCObjectStreamer.h | 3 +-- include/llvm/MC/MCStreamer.h | 2 +- lib/MC/MCAsmInfo.cpp | 1 + lib/MC/MCAsmStreamer.cpp | 35 +++++++++++++++++++++++++---- lib/MC/MCDwarf.cpp | 13 ++++++++--- lib/MC/MCLoggingStreamer.cpp | 3 +-- lib/MC/MCNullStreamer.cpp | 2 +- lib/MC/MCObjectStreamer.cpp | 2 +- lib/Target/PTX/PTXMCAsmStreamer.cpp | 5 ++--- lib/Target/PowerPC/PPCMCAsmInfo.cpp | 4 ++++ lib/Target/X86/X86MCAsmInfo.cpp | 4 ++++ test/MC/MachO/empty-dwarf-lines.s | 2 +- 13 files changed, 66 insertions(+), 18 deletions(-) diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h index d53318c6631..0e6c4e7c75e 100644 --- a/include/llvm/MC/MCAsmInfo.h +++ b/include/llvm/MC/MCAsmInfo.h @@ -197,6 +197,13 @@ namespace llvm { /// HasSetDirective - True if the assembler supports the .set directive. bool HasSetDirective; // Defaults to true. + /// NeedsSetToChangeDiffSize - True if the assembler requires that we do + /// Lc = a - b + /// .long Lc + /// instead of doing + /// .long a - b + bool NeedsSetToChangeDiffSize; // Defaults to false. + /// HasLCOMMDirective - This is true if the target supports the .lcomm /// directive. bool HasLCOMMDirective; // Defaults to false. @@ -400,6 +407,7 @@ namespace llvm { return ExternDirective; } bool hasSetDirective() const { return HasSetDirective; } + bool needsSetToChangeDiffSize() const { return NeedsSetToChangeDiffSize; } bool hasLCOMMDirective() const { return HasLCOMMDirective; } bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} bool getCOMMDirectiveAlignmentIsInBytes() const { diff --git a/include/llvm/MC/MCObjectStreamer.h b/include/llvm/MC/MCObjectStreamer.h index a3f532d8c00..d130ba4bcda 100644 --- a/include/llvm/MC/MCObjectStreamer.h +++ b/include/llvm/MC/MCObjectStreamer.h @@ -60,8 +60,7 @@ public: /// @{ virtual void EmitLabel(MCSymbol *Symbol); - virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace, - bool UseSet = false); + virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace); virtual void EmitULEB128Value(const MCExpr *Value, unsigned AddrSpace = 0); virtual void EmitSLEB128Value(const MCExpr *Value, unsigned AddrSpace = 0); virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol); diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h index 16646c96d3e..d89ee9ae126 100644 --- a/include/llvm/MC/MCStreamer.h +++ b/include/llvm/MC/MCStreamer.h @@ -242,7 +242,7 @@ namespace llvm { /// @param Size - The size of the integer (in bytes) to emit. This must /// match a native machine width. virtual void EmitValue(const MCExpr *Value, unsigned Size, - unsigned AddrSpace = 0, bool UseSet = false) = 0; + unsigned AddrSpace = 0) = 0; /// EmitIntValue - Special case of EmitValue that avoids the client having /// to pass in a MCExpr for constant integers. diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp index 9cf4019e312..1bc63d03fba 100644 --- a/lib/MC/MCAsmInfo.cpp +++ b/lib/MC/MCAsmInfo.cpp @@ -54,6 +54,7 @@ MCAsmInfo::MCAsmInfo() { GPRel32Directive = 0; GlobalDirective = "\t.globl\t"; HasSetDirective = true; + NeedsSetToChangeDiffSize = false; HasLCOMMDirective = false; COMMDirectiveAlignmentIsInBytes = true; HasDotTypeDotSizeDirective = true; diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp index 40a234ea85f..ab807edd9ea 100644 --- a/lib/MC/MCAsmStreamer.cpp +++ b/lib/MC/MCAsmStreamer.cpp @@ -44,6 +44,8 @@ class MCAsmStreamer : public MCStreamer { unsigned IsVerboseAsm : 1; unsigned ShowInst : 1; + bool needsSet(const MCExpr *Value); + public: MCAsmStreamer(MCContext &Context, formatted_raw_ostream &os, bool isLittleEndian, bool isVerboseAsm, @@ -150,8 +152,7 @@ public: virtual void EmitBytes(StringRef Data, unsigned AddrSpace); - virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace, - bool UseSet = false); + virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace); virtual void EmitIntValue(uint64_t Value, unsigned Size, unsigned AddrSpace = 0); @@ -511,8 +512,34 @@ void MCAsmStreamer::EmitIntValue(uint64_t Value, unsigned Size, EmitValue(MCConstantExpr::Create(Value, getContext()), Size, AddrSpace); } +static bool hasSymbolDifference(const MCExpr *Value) { + switch (Value->getKind()) { + case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!"); + case MCExpr::Constant: + case MCExpr::SymbolRef: + return false; + case MCExpr::Unary: + return hasSymbolDifference(cast(Value)->getSubExpr()); + case MCExpr::Binary: { + const MCBinaryExpr *BE = cast(Value); + if (BE->getOpcode() == MCBinaryExpr::Sub && + BE->getLHS()->getKind() == MCExpr::SymbolRef && + BE->getRHS()->getKind() == MCExpr::SymbolRef) + return true; + return hasSymbolDifference(BE->getLHS()) || + hasSymbolDifference(BE->getRHS()); + } + } + llvm_unreachable("Switch covers all cases"); +} + +bool MCAsmStreamer::needsSet(const MCExpr *Value) { + return getContext().getAsmInfo().needsSetToChangeDiffSize() && + hasSymbolDifference(Value); +} + void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size, - unsigned AddrSpace, bool UseSet) { + unsigned AddrSpace) { assert(CurSection && "Cannot emit contents before setting section!"); const char *Directive = 0; switch (Size) { @@ -538,7 +565,7 @@ void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size, } assert(Directive && "Invalid size for machine code value!"); - if (UseSet && MAI.hasSetDirective()) { + if (needsSet(Value)) { MCSymbol *SetLabel = getContext().CreateTempSymbol(); EmitAssignment(SetLabel, Value); OS << Directive << *SetLabel; diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp index a33b0c596ba..1b1d5097042 100644 --- a/lib/MC/MCDwarf.cpp +++ b/lib/MC/MCDwarf.cpp @@ -213,8 +213,15 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS, // The first 4 bytes is the total length of the information for this // compilation unit (not including these 4 bytes for the length). - MCOS->EmitValue(MakeStartMinusEndExpr(MCOS, LineStartSym, LineEndSym, 4), - 4, 0, true /*UseSet*/); + // FIXME: We create the dummy TotalLength variable because LineEndSym points + // to the end of the section and the darwin assembler doesn't consider that + // difference an assembly time constant. It might be better for this to be + // proected by a flag. + MCSymbol *TotalLength = MCOS->getContext().CreateTempSymbol(); + MCOS->EmitAssignment(TotalLength, + MakeStartMinusEndExpr(MCOS, LineStartSym, LineEndSym, + 4)); + MCOS->EmitSymbolValue(TotalLength, 4, 0); // Next 2 bytes is the Version, which is Dwarf 2. MCOS->EmitIntValue(2, 2); @@ -228,7 +235,7 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS, // length of the prologue. MCOS->EmitValue(MakeStartMinusEndExpr(MCOS, LineStartSym, ProEndSym, (4 + 2 + 4)), - 4, 0, true /*UseSet*/); + 4, 0); // Parameters of the state machine, are next. MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1); diff --git a/lib/MC/MCLoggingStreamer.cpp b/lib/MC/MCLoggingStreamer.cpp index 6cbef0b0250..134554b8006 100644 --- a/lib/MC/MCLoggingStreamer.cpp +++ b/lib/MC/MCLoggingStreamer.cpp @@ -154,8 +154,7 @@ public: return Child->EmitBytes(Data, AddrSpace); } - virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace, - bool UseSet = false){ + virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace){ LogCall("EmitValue"); return Child->EmitValue(Value, Size, AddrSpace); } diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp index 86ab628e602..c8f9c636174 100644 --- a/lib/MC/MCNullStreamer.cpp +++ b/lib/MC/MCNullStreamer.cpp @@ -69,7 +69,7 @@ namespace { virtual void EmitBytes(StringRef Data, unsigned AddrSpace) {} virtual void EmitValue(const MCExpr *Value, unsigned Size, - unsigned AddrSpace, bool UseSet = false) {} + unsigned AddrSpace) {} virtual void EmitULEB128Value(const MCExpr *Value, unsigned AddrSpace = 0) {} virtual void EmitSLEB128Value(const MCExpr *Value, diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp index 1538a589966..ad8fb495840 100644 --- a/lib/MC/MCObjectStreamer.cpp +++ b/lib/MC/MCObjectStreamer.cpp @@ -77,7 +77,7 @@ const MCExpr *MCObjectStreamer::AddValueSymbols(const MCExpr *Value) { } void MCObjectStreamer::EmitValue(const MCExpr *Value, unsigned Size, - unsigned AddrSpace, bool UseSet) { + unsigned AddrSpace) { assert(AddrSpace == 0 && "Address space must be 0!"); MCDataFragment *DF = getOrCreateDataFragment(); diff --git a/lib/Target/PTX/PTXMCAsmStreamer.cpp b/lib/Target/PTX/PTXMCAsmStreamer.cpp index 8043baf8cfc..4e517ad76a2 100644 --- a/lib/Target/PTX/PTXMCAsmStreamer.cpp +++ b/lib/Target/PTX/PTXMCAsmStreamer.cpp @@ -147,8 +147,7 @@ public: virtual void EmitBytes(StringRef Data, unsigned AddrSpace); - virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace, - bool UseSet = false); + virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace); virtual void EmitULEB128Value(const MCExpr *Value, unsigned AddrSpace = 0); virtual void EmitSLEB128Value(const MCExpr *Value, unsigned AddrSpace = 0); virtual void EmitGPRel32Value(const MCExpr *Value); @@ -361,7 +360,7 @@ void PTXMCAsmStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { } void PTXMCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size, - unsigned AddrSpace, bool UseSet) { + unsigned AddrSpace) { assert(CurSection && "Cannot emit contents before setting section!"); const char *Directive = 0; switch (Size) { diff --git a/lib/Target/PowerPC/PPCMCAsmInfo.cpp b/lib/Target/PowerPC/PPCMCAsmInfo.cpp index 3644c79d041..89c8cb664c7 100644 --- a/lib/Target/PowerPC/PPCMCAsmInfo.cpp +++ b/lib/Target/PowerPC/PPCMCAsmInfo.cpp @@ -21,6 +21,10 @@ PPCMCAsmInfoDarwin::PPCMCAsmInfoDarwin(bool is64Bit) { if (!is64Bit) Data64bitsDirective = 0; // We can't emit a 64-bit unit in PPC32 mode. + + if (is64Bit) + NeedsSetToChangeDiffSize = true; + AssemblerDialect = 1; // New-Style mnemonics. SupportsDebugInformation= true; // Debug information. } diff --git a/lib/Target/X86/X86MCAsmInfo.cpp b/lib/Target/X86/X86MCAsmInfo.cpp index f45fdf5a3fb..1ac2d7e6c6d 100644 --- a/lib/Target/X86/X86MCAsmInfo.cpp +++ b/lib/Target/X86/X86MCAsmInfo.cpp @@ -56,6 +56,10 @@ X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &Triple) { if (!is64Bit) Data64bitsDirective = 0; // we can't emit a 64-bit unit + // FIXME: Darwin 10 doesn't need this. + if (is64Bit) + NeedsSetToChangeDiffSize = true; + // Use ## as a comment string so that .s files generated by llvm can go // through the GCC preprocessor without causing an error. This is needed // because "clang foo.s" runs the C preprocessor, which is usually reserved diff --git a/test/MC/MachO/empty-dwarf-lines.s b/test/MC/MachO/empty-dwarf-lines.s index 29ef218fddc..8d06d7363da 100644 --- a/test/MC/MachO/empty-dwarf-lines.s +++ b/test/MC/MachO/empty-dwarf-lines.s @@ -17,7 +17,7 @@ _c: // CHECK-NEXT: ('offset', 452) // CHECK-NEXT: ('alignment', 0) // CHECK-NEXT: ('reloc_offset', 496) -// CHECK-NEXT: ('num_reloc', 4) +// CHECK-NEXT: ('num_reloc', 2) // CHECK-NEXT: ('flags', 0x2000000) // CHECK-NEXT: ('reserved1', 0) // CHECK-NEXT: ('reserved2', 0)