From 6c56decee0607db092e932b20f45c2825bc31684 Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Thu, 11 Jun 2015 18:58:08 +0000 Subject: [PATCH] Generalize emitAbsoluteSymbolDiff. This makes emitAbsoluteSymbolDiff always succeed and moves logic from the asm printer to it. The object one now also works on ELF. If two symbols are in the same fragment, we will never move them apart. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239552 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/MC/MCObjectStreamer.h | 2 +- include/llvm/MC/MCStreamer.h | 8 +++----- lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 20 +------------------- lib/MC/MCObjectStreamer.cpp | 15 ++++++--------- lib/MC/MCStreamer.cpp | 19 +++++++++++++++++++ 5 files changed, 30 insertions(+), 34 deletions(-) diff --git a/include/llvm/MC/MCObjectStreamer.h b/include/llvm/MC/MCObjectStreamer.h index 462b3b484c5..131da07c23a 100644 --- a/include/llvm/MC/MCObjectStreamer.h +++ b/include/llvm/MC/MCObjectStreamer.h @@ -136,7 +136,7 @@ public: /// /// \pre Offset of \c Hi is greater than the offset \c Lo. /// \return true on success. - bool emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, + void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, unsigned Size) override; bool mayHaveInstructions(MCSection &Sec) const override; diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h index 628fb768856..4dd53df25ec 100644 --- a/include/llvm/MC/MCStreamer.h +++ b/include/llvm/MC/MCStreamer.h @@ -636,14 +636,12 @@ public: unsigned Isa, unsigned Discriminator, StringRef FileName); - /// Emit the absolute difference between two symbols if possible. + /// Emit the absolute difference between two symbols. /// /// \pre Offset of \c Hi is greater than the offset \c Lo. /// \return true on success. - virtual bool emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, - unsigned Size) { - return false; - } + virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, + unsigned Size); virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID); virtual void EmitCFISections(bool EH, bool Debug); diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp index 04b936afa06..dd1d9a980d8 100644 --- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp +++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp @@ -1590,25 +1590,7 @@ void AsmPrinter::EmitInt32(int Value) const { /// .set if it avoids relocations. void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, unsigned Size) const { - if (!MAI->doesDwarfUseRelocationsAcrossSections()) - if (OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size)) - return; - - // Get the Hi-Lo expression. - const MCExpr *Diff = - MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, OutContext), - MCSymbolRefExpr::create(Lo, OutContext), - OutContext); - - if (!MAI->doesSetDirectiveSuppressesReloc()) { - OutStreamer->EmitValue(Diff, Size); - return; - } - - // Otherwise, emit with .set (aka assignment). - MCSymbol *SetLabel = createTempSymbol("set"); - OutStreamer->EmitAssignment(SetLabel, Diff); - OutStreamer->EmitSymbolValue(SetLabel, Size); + OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size); } /// EmitLabelPlusOffset - Emit something like ".long Label+Offset" diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp index 6de02bcb02d..a73c171bd1c 100644 --- a/lib/MC/MCObjectStreamer.cpp +++ b/lib/MC/MCObjectStreamer.cpp @@ -54,21 +54,18 @@ void MCObjectStreamer::flushPendingLabels(MCFragment *F, uint64_t FOffset) { } } -bool MCObjectStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, +void MCObjectStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, unsigned Size) { - // Must both be assigned to the same (valid) fragment. - if (!Hi->getFragment() || Hi->getFragment() != Lo->getFragment()) - return false; - - // Must be a data fragment. - if (!isa(Hi->getFragment())) - return false; + // If not assigned to the same (valid) fragment, fallback. + if (!Hi->getFragment() || Hi->getFragment() != Lo->getFragment()) { + MCStreamer::emitAbsoluteSymbolDiff(Hi, Lo, Size); + return; + } assert(Hi->getOffset() >= Lo->getOffset() && "Expected Hi to be greater than Lo"); EmitIntValue(Hi->getOffset() - Lo->getOffset(), Size); - return true; } void MCObjectStreamer::reset() { diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp index 011969a3da0..349de97a17c 100644 --- a/lib/MC/MCStreamer.cpp +++ b/lib/MC/MCStreamer.cpp @@ -638,6 +638,25 @@ void MCStreamer::EmitInstruction(const MCInst &Inst, visitUsedExpr(*Inst.getOperand(i).getExpr()); } +void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, + unsigned Size) { + // Get the Hi-Lo expression. + const MCExpr *Diff = + MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context), + MCSymbolRefExpr::create(Lo, Context), Context); + + const MCAsmInfo *MAI = Context.getAsmInfo(); + if (!MAI->doesSetDirectiveSuppressesReloc()) { + EmitValue(Diff, Size); + return; + } + + // Otherwise, emit with .set (aka assignment). + MCSymbol *SetLabel = Context.createTempSymbol("set", true); + EmitAssignment(SetLabel, Diff); + EmitSymbolValue(SetLabel, Size); +} + void MCStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {} void MCStreamer::EmitThumbFunc(MCSymbol *Func) {} void MCStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {} -- 2.34.1