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[GlobalISel] Fix wrong invocation of `getParamStackAlign` (NFC) 

The function template `CallLowering::setArgFlags` is invoked both
for arguments and return values. In the latter case, it calls
`getParamStackAlign` with argument index `~0u`. Nothing wrong
happens now, as the argument is safely incremented back to 0
inside `getParamStackAlign` (the type is `unsigned`), but in
principle it's fragile and may become incorrect.

Differential Revision: https://reviews.llvm.org/D102004
This commit is contained in:
Momchil Velikov 2021-05-10 11:19:13 +01:00
parent 407a33889d
commit f3139b20a0
1 changed files with 10 additions and 7 deletions
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17
llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
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@ -154,8 +154,9 @@ void CallLowering::setArgFlags(CallLowering::ArgInfo &Arg, unsigned OpIdx,
const AttributeList &Attrs = FuncInfo.getAttributes();
addArgFlagsFromAttributes(Flags, Attrs, OpIdx);
Align MemAlign;
Align MemAlign = DL.getABITypeAlign(Arg.Ty);
if (Flags.isByVal() || Flags.isInAlloca() || Flags.isPreallocated()) {
assert(OpIdx >= AttributeList::FirstArgIndex);
Type *ElementTy = cast<PointerType>(Arg.Ty)->getElementType();
auto Ty = Attrs.getAttribute(OpIdx, Attribute::ByVal).getValueAsType();
@ -163,16 +164,18 @@ void CallLowering::setArgFlags(CallLowering::ArgInfo &Arg, unsigned OpIdx,
// For ByVal, alignment should be passed from FE. BE will guess if
// this info is not there but there are cases it cannot get right.
if (auto ParamAlign = FuncInfo.getParamStackAlign(OpIdx - 1))
if (auto ParamAlign =
FuncInfo.getParamStackAlign(OpIdx - AttributeList::FirstArgIndex))
MemAlign = *ParamAlign;
else if ((ParamAlign = FuncInfo.getParamAlign(OpIdx - 1)))
else if ((ParamAlign =
FuncInfo.getParamAlign(OpIdx - AttributeList::FirstArgIndex)))
MemAlign = *ParamAlign;
else
MemAlign = Align(getTLI()->getByValTypeAlignment(ElementTy, DL));
} else if (auto ParamAlign = FuncInfo.getParamStackAlign(OpIdx - 1)) {
MemAlign = *ParamAlign;
} else {
MemAlign = Align(DL.getABITypeAlign(Arg.Ty));
} else if (OpIdx >= AttributeList::FirstArgIndex) {
if (auto ParamAlign =
FuncInfo.getParamStackAlign(OpIdx - AttributeList::FirstArgIndex))
MemAlign = *ParamAlign;
}
Flags.setMemAlign(MemAlign);
Flags.setOrigAlign(DL.getABITypeAlign(Arg.Ty));