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Always reserve space for 8 spilled GPRs. GCC apparently assumes that this

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space will be available, even if the callee isn't varargs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28571 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-05-30 21:21:04 +00:00
parent ac28588def
commit 7b05350906
1 changed files with 7 additions and 12 deletions
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19
lib/Target/PowerPC/PPCISelLowering.cpp
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@ -916,18 +916,13 @@ static SDOperand LowerCALL(SDOperand Op, SelectionDAG &DAG) {
for (unsigned i = 0; i != NumOps; ++i)
NumBytes += MVT::getSizeInBits(Op.getOperand(5+2*i).getValueType())/8;
// If we are calling what looks like a varargs function on the caller side,
// there are two cases:
// 1) The callee uses va_start.
// 2) The callee doesn't use va_start.
//
// In the case of #1, the prolog code will store up to 8 GPR argument
// registers to the stack, allowing va_start to index over them in memory.
// Because we cannot tell the difference (on the caller side) between #1/#2,
// we have to conservatively assume we have #1. As such, make sure we have
// at least enough stack space for the caller to store the 8 GPRs.
if (isVarArg && Op.getNumOperands() > 5 && NumBytes < 56)
NumBytes = 56;
// The prolog code of the callee may store up to 8 GPR argument registers to
// the stack, allowing va_start to index over them in memory if its varargs.
// Because we cannot tell if this is needed on the caller side, we have to
// conservatively assume that it is needed. As such, make sure we have at
// least enough stack space for the caller to store the 8 GPRs.
if (NumBytes < 24+8*4)
NumBytes = 24+8*4;
// Adjust the stack pointer for the new arguments...
// These operations are automatically eliminated by the prolog/epilog pass