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Another sibcall bug. If caller and callee calling conventions differ, then it's only safe to do a tail call if the results are returned in the same way. 

llvm-svn: 102683
This commit is contained in:
Evan Cheng 2010-04-30 01:12:32 +00:00
parent 4a623eed26
commit 5117a555e0
2 changed files with 53 additions and 3 deletions
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38
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -2326,9 +2326,11 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
// If -tailcallopt is specified, make fastcc functions tail-callable.
const MachineFunction &MF = DAG.getMachineFunction();
const Function *CallerF = DAG.getMachineFunction().getFunction();
CallingConv::ID CallerCC = CallerF->getCallingConv();
bool CCMatch = CallerCC == CalleeCC;
if (GuaranteedTailCallOpt) {
if (IsTailCallConvention(CalleeCC) &&
CallerF->getCallingConv() == CalleeCC)
if (IsTailCallConvention(CalleeCC) && CCMatch)
return true;
return false;
}
@ -2366,13 +2368,43 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
CCState CCInfo(CalleeCC, false, getTargetMachine(),
RVLocs, *DAG.getContext());
CCInfo.AnalyzeCallResult(Ins, RetCC_X86);
for (unsigned i = 0; i != RVLocs.size(); ++i) {
for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
CCValAssign &VA = RVLocs[i];
if (VA.getLocReg() == X86::ST0 || VA.getLocReg() == X86::ST1)
return false;
}
}
// If the calling conventions do not match, then we'd better make sure the
// results are returned in the same way as what the caller expects.
if (!CCMatch) {
SmallVector<CCValAssign, 16> RVLocs1;
CCState CCInfo1(CalleeCC, false, getTargetMachine(),
RVLocs1, *DAG.getContext());
CCInfo1.AnalyzeCallResult(Ins, RetCC_X86);
SmallVector<CCValAssign, 16> RVLocs2;
CCState CCInfo2(CallerCC, false, getTargetMachine(),
RVLocs2, *DAG.getContext());
CCInfo2.AnalyzeCallResult(Ins, RetCC_X86);
if (RVLocs1.size() != RVLocs2.size())
return false;
for (unsigned i = 0, e = RVLocs1.size(); i != e; ++i) {
if (RVLocs1[i].isRegLoc() != RVLocs2[i].isRegLoc())
return false;
if (RVLocs1[i].getLocInfo() != RVLocs2[i].getLocInfo())
return false;
if (RVLocs1[i].isRegLoc()) {
if (RVLocs1[i].getLocReg() != RVLocs2[i].getLocReg())
return false;
} else {
if (RVLocs1[i].getLocMemOffset() != RVLocs2[i].getLocMemOffset())
return false;
}
}
}
// If the callee takes no arguments then go on to check the results of the
// call.
if (!Outs.empty()) {

18
llvm/test/CodeGen/X86/sibcall.ll
View File

@ -313,3 +313,21 @@ entry:
}
declare void @foo()
; If caller / callee calling convention mismatch then check if the return
; values are returned in the same registers.
; rdar://7874780
define double @t20(double %x) nounwind {
entry:
; 32: t20:
; 32: call {{_?}}foo20
; 32: fldl (%esp)
; 64: t20:
; 64: jmp {{_?}}foo20
%0 = tail call fastcc double @foo20(double %x) nounwind
ret double %0
}
declare fastcc double @foo20(double) nounwind