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[SVE] Fix ubsan issues in DecodeIITType 

In an earlier patch I removed the need for
IITDescriptor::ScalableVecArgument, which involved changing
DecodeIITType to pull out the last IIT_Info from the list. However,
it turns out this is unsafe and causes ubsan failures. I've tried to
fix this a different way by simply passing the last IIT_Info as an
additional argument to DecodeIITType.

Differential Revision: https://reviews.llvm.org/D81057
This commit is contained in:
David Sherwood 2020-06-02 14:44:24 +01:00
parent 8d74de9de6
commit a3e3986be1
1 changed files with 18 additions and 21 deletions
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39
llvm/lib/IR/Function.cpp
View File

@ -752,14 +752,11 @@ enum IIT_Info {
};
static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
IIT_Info LastInfo,
SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
using namespace Intrinsic;
bool IsScalableVector = false;
if (NextElt > 0) {
IIT_Info LastInfo = IIT_Info(Infos[NextElt - 1]);
IsScalableVector = (LastInfo == IIT_SCALABLE_VEC);
}
bool IsScalableVector = (LastInfo == IIT_SCALABLE_VEC);
IIT_Info Info = IIT_Info(Infos[NextElt++]);
unsigned StructElts = 2;
@ -815,52 +812,52 @@ static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
return;
case IIT_V1:
OutputTable.push_back(IITDescriptor::getVector(1, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V2:
OutputTable.push_back(IITDescriptor::getVector(2, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V4:
OutputTable.push_back(IITDescriptor::getVector(4, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V8:
OutputTable.push_back(IITDescriptor::getVector(8, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V16:
OutputTable.push_back(IITDescriptor::getVector(16, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V32:
OutputTable.push_back(IITDescriptor::getVector(32, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V64:
OutputTable.push_back(IITDescriptor::getVector(64, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V128:
OutputTable.push_back(IITDescriptor::getVector(128, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V512:
OutputTable.push_back(IITDescriptor::getVector(512, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_V1024:
OutputTable.push_back(IITDescriptor::getVector(1024, IsScalableVector));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_PTR:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
case IIT_ANYPTR: { // [ANYPTR addrspace, subtype]
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
Infos[NextElt++]));
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
}
case IIT_ARG: {
@ -923,7 +920,7 @@ static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
for (unsigned i = 0; i != StructElts; ++i)
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
}
case IIT_SUBDIVIDE2_ARG: {
@ -945,7 +942,7 @@ static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
return;
}
case IIT_SCALABLE_VEC: {
DecodeIITType(NextElt, Infos, OutputTable);
DecodeIITType(NextElt, Infos, Info, OutputTable);
return;
}
case IIT_VEC_OF_BITCASTS_TO_INT: {
@ -990,9 +987,9 @@ void Intrinsic::getIntrinsicInfoTableEntries(ID id,
}
// Okay, decode the table into the output vector of IITDescriptors.
DecodeIITType(NextElt, IITEntries, T);
DecodeIITType(NextElt, IITEntries, IIT_Done, T);
while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
DecodeIITType(NextElt, IITEntries, T);
DecodeIITType(NextElt, IITEntries, IIT_Done, T);
}
static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,