diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/Analysis.cpp | 18 | ||||
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 23 |
2 files changed, 35 insertions, 6 deletions
diff --git a/lib/CodeGen/Analysis.cpp b/lib/CodeGen/Analysis.cpp index 2cf3c66..36638c3 100644 --- a/lib/CodeGen/Analysis.cpp +++ b/lib/CodeGen/Analysis.cpp @@ -19,6 +19,7 @@ #include "llvm/LLVMContext.h" #include "llvm/Module.h" #include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/SelectionDAG.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetLowering.h" #include "llvm/Target/TargetOptions.h" @@ -283,3 +284,20 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attributes CalleeRetAttr, return true; } +bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node, + const TargetLowering &TLI) { + const Function *F = DAG.getMachineFunction().getFunction(); + + // Conservatively require the attributes of the call to match those of + // the return. Ignore noalias because it doesn't affect the call sequence. + unsigned CallerRetAttr = F->getAttributes().getRetAttributes(); + if (CallerRetAttr & ~Attribute::NoAlias) + return false; + + // It's not safe to eliminate the sign / zero extension of the return value. + if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt)) + return false; + + // Check if the only use is a function return node. + return TLI.isUsedByReturnOnly(Node); +} diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp index 6f6dcc0..4b970e0 100644 --- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -11,13 +11,14 @@ // //===----------------------------------------------------------------------===// -#include "llvm/CodeGen/SelectionDAG.h" +#include "llvm/Analysis/DebugInfo.h" +#include "llvm/CodeGen/Analysis.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineJumpTableInfo.h" #include "llvm/CodeGen/MachineModuleInfo.h" -#include "llvm/Analysis/DebugInfo.h" #include "llvm/CodeGen/PseudoSourceValue.h" +#include "llvm/CodeGen/SelectionDAG.h" #include "llvm/Target/TargetFrameInfo.h" #include "llvm/Target/TargetLowering.h" #include "llvm/Target/TargetData.h" @@ -1948,12 +1949,20 @@ SDValue SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, SDNode *Node, // Splice the libcall in wherever FindInputOutputChains tells us to. const Type *RetTy = Node->getValueType(0).getTypeForEVT(*DAG.getContext()); + + // isTailCall may be true since the callee does not reference caller stack + // frame. Check if it's in the right position. + bool isTailCall = isInTailCallPosition(DAG, Node, TLI); std::pair<SDValue, SDValue> CallInfo = TLI.LowerCallTo(InChain, RetTy, isSigned, !isSigned, false, false, - 0, TLI.getLibcallCallingConv(LC), false, + 0, TLI.getLibcallCallingConv(LC), isTailCall, /*isReturnValueUsed=*/true, Callee, Args, DAG, Node->getDebugLoc()); + if (!CallInfo.second.getNode()) + // It's a tailcall, return the chain (which is the DAG root). + return DAG.getRoot(); + // Legalize the call sequence, starting with the chain. This will advance // the LastCALLSEQ_END to the legalized version of the CALLSEQ_END node that // was added by LowerCallTo (guaranteeing proper serialization of calls). @@ -1988,7 +1997,7 @@ SelectionDAGLegalize::ExpandChainLibCall(RTLIB::Libcall LC, const Type *RetTy = Node->getValueType(0).getTypeForEVT(*DAG.getContext()); std::pair<SDValue, SDValue> CallInfo = TLI.LowerCallTo(InChain, RetTy, isSigned, !isSigned, false, false, - 0, TLI.getLibcallCallingConv(LC), false, + 0, TLI.getLibcallCallingConv(LC), /*isTailCall=*/false, /*isReturnValueUsed=*/true, Callee, Args, DAG, Node->getDebugLoc()); @@ -2558,7 +2567,8 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node, TargetLowering::ArgListTy Args; std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(Node->getOperand(0), Type::getVoidTy(*DAG.getContext()), - false, false, false, false, 0, CallingConv::C, false, + false, false, false, false, 0, CallingConv::C, + /*isTailCall=*/false, /*isReturnValueUsed=*/true, DAG.getExternalSymbol("__sync_synchronize", TLI.getPointerTy()), @@ -2609,7 +2619,8 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node, TargetLowering::ArgListTy Args; std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(Node->getOperand(0), Type::getVoidTy(*DAG.getContext()), - false, false, false, false, 0, CallingConv::C, false, + false, false, false, false, 0, CallingConv::C, + /*isTailCall=*/false, /*isReturnValueUsed=*/true, DAG.getExternalSymbol("abort", TLI.getPointerTy()), Args, DAG, dl); |