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[IR] Add overflow check in AllocaInst::getAllocationSize #97170

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Merged
merged 1 commit into from
Jul 3, 2024
Merged

[IR] Add overflow check in AllocaInst::getAllocationSize #97170

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17 changes: 13 additions & 4 deletions llvm/lib/IR/Instructions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include "llvm/IR/Value.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CheckedArithmetic.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/ModRef.h"
Expand Down Expand Up @@ -65,17 +66,25 @@ AllocaInst::getAllocationSize(const DataLayout &DL) const {
if (!C)
return std::nullopt;
assert(!Size.isScalable() && "Array elements cannot have a scalable size");
Size *= C->getZExtValue();
auto CheckedProd =
checkedMulUnsigned(Size.getKnownMinValue(), C->getZExtValue());
if (!CheckedProd)
return std::nullopt;
return TypeSize::getFixed(*CheckedProd);
}
return Size;
}

std::optional<TypeSize>
AllocaInst::getAllocationSizeInBits(const DataLayout &DL) const {
std::optional<TypeSize> Size = getAllocationSize(DL);
if (Size)
return *Size * 8;
return std::nullopt;
if (!Size)
return std::nullopt;
auto CheckedProd = checkedMulUnsigned(Size->getKnownMinValue(),
static_cast<TypeSize::ScalarTy>(8));
if (!CheckedProd)
return std::nullopt;
return TypeSize::get(*CheckedProd, Size->isScalable());
}

//===----------------------------------------------------------------------===//
Expand Down
3 changes: 3 additions & 0 deletions llvm/unittests/IR/InstructionsTest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1750,6 +1750,7 @@ TEST(InstructionsTest, AllocaInst) {
%F = alloca [2 x half]
%G = alloca [2 x [3 x i128]]
%H = alloca %T
%I = alloca i32, i64 9223372036854775807
ret void
}
)");
Expand All @@ -1766,6 +1767,7 @@ TEST(InstructionsTest, AllocaInst) {
AllocaInst &F = cast<AllocaInst>(*It++);
AllocaInst &G = cast<AllocaInst>(*It++);
AllocaInst &H = cast<AllocaInst>(*It++);
AllocaInst &I = cast<AllocaInst>(*It++);
EXPECT_EQ(A.getAllocationSizeInBits(DL), TypeSize::getFixed(32));
EXPECT_EQ(B.getAllocationSizeInBits(DL), TypeSize::getFixed(128));
EXPECT_FALSE(C.getAllocationSizeInBits(DL));
Expand All @@ -1774,6 +1776,7 @@ TEST(InstructionsTest, AllocaInst) {
EXPECT_EQ(F.getAllocationSizeInBits(DL), TypeSize::getFixed(32));
EXPECT_EQ(G.getAllocationSizeInBits(DL), TypeSize::getFixed(768));
EXPECT_EQ(H.getAllocationSizeInBits(DL), TypeSize::getFixed(160));
EXPECT_FALSE(I.getAllocationSizeInBits(DL));
}

TEST(InstructionsTest, InsertAtBegin) {
Expand Down
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