From 60ec248148c52a47cecf8b660c32a0e7568a8a00 Mon Sep 17 00:00:00 2001 From: Jason Liu Date: Thu, 6 Jun 2019 19:13:36 +0000 Subject: [AIX] Implement function descriptor on SDAG Summary: (1) Function descriptor on AIX On AIX, a called routine may have 2 distinct symbols associated with it: * A function descriptor (Name) * A function entry point (.Name) The descriptor structure on AIX is the same as those in the ELF V1 ABI: * The address of the entry point of the function. * The TOC base address for the function. * The environment pointer. The descriptor symbol uses the same name as the source level function in C. The function entry point is analogous to the symbol we would generate for a function in a non-descriptor-based ABI, except that it is renamed by prepending a ".". Which symbol gets referenced depends on the context: * Taking the address of the function references the descriptor symbol. * Calling the function references the entry point symbol. (2) Speaking of implementation on AIX, for direct function call target, we create proper MCSymbol SDNode(e.g . ".foo") while constructing SDAG to replace original TargetGlobalAddress SDNode. Then down the path, we can take advantage of this MCSymbol. Patch by: Xiangling_L Reviewed by: sfertile, hubert.reinterpretcast, jasonliu, syzaara Differential Revision: https://reviews.llvm.org/D62532 llvm-svn: 362735 --- llvm/lib/CodeGen/LLVMTargetMachine.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'llvm/lib/CodeGen/LLVMTargetMachine.cpp') diff --git a/llvm/lib/CodeGen/LLVMTargetMachine.cpp b/llvm/lib/CodeGen/LLVMTargetMachine.cpp index 1d10a6c9afd..886ae7e94ad 100644 --- a/llvm/lib/CodeGen/LLVMTargetMachine.cpp +++ b/llvm/lib/CodeGen/LLVMTargetMachine.cpp @@ -201,6 +201,15 @@ bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM, return true; if (!TargetPassConfig::willCompleteCodeGenPipeline()) { + if (this->getTargetTriple().isOSAIX()) { + // On AIX, we might manifest MCSymbols during SDAG lowering. For MIR + // testing to be meaningful, we need to ensure that the symbols created + // are MCSymbolXCOFF variants, which requires that + // the TargetLoweringObjectFile instance has been initialized. + MCContext &Ctx = MMI->getContext(); + const_cast(*this->getObjFileLowering()) + .Initialize(Ctx, *this); + } PM.add(createPrintMIRPass(Out)); } else if (addAsmPrinter(PM, Out, DwoOut, FileType, MMI->getContext())) return true; -- cgit v1.2.3