Richard Pennington
2011-Sep-17 21:20 UTC
[LLVMdev] Problem with Linux PPC64 assembly output.
The latest binutils (2.21.2) assembler for the PPC64 complains about the .size directive emitted by LLVM as not containing an absolute expression. An example: __umodsi3: .quad .L.__umodsi3,.TOC. at tocbase .previous .L.__umodsi3: mflr 0 [snip] mtlr 0 blr .Ltmp0: .size __umodsi3, .Ltmp0-__umodsi3 The correct size expression should be .Ltmp0-.L.__umodsi3 The code which does this is in AsmPrinter.cpp: // If the target wants a .size directive for the size of the function, emit // it. if (MAI->hasDotTypeDotSizeDirective()) { // Create a symbol for the end of function, so we can get the size as // difference between the function label and the temp label. MCSymbol *FnEndLabel = OutContext.CreateTempSymbol(); OutStreamer.EmitLabel(FnEndLabel); const MCExpr *SizeExp MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext), MCSymbolRefExpr::Create(CurrentFnSym, OutContext), OutContext); OutStreamer.EmitELFSize(CurrentFnSym, SizeExp); } I've filed a bug for this: http://llvm.org/bugs/show_bug.cgi?id=10951 This looks a little tricky to fix since there is no easy hook that I can find to override how the .size directive is output. Anyone have any suggestions, or have I missed something? -Rich