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[BOLT][NFC] Fix undefined behavior in encodeAnnotationImm

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Fix UBSan-reported issue in MCPlusBuilder::encodeAnnotationImm (left shift of a
negative value).

Test Plan:
```
ninja check-bolt
...
PASS: BOLT-Unit :: Core/./CoreTests/AArch64/MCPlusBuilderTester.Annotation/0 (1 of 140)
PASS: BOLT-Unit :: Core/./CoreTests/X86/MCPlusBuilderTester.Annotation/0 (131 of 134)
```

Reviewed By: maksfb, yota9

Differential Revision: https://reviews.llvm.org/D120260
This commit is contained in:
Amir Ayupov 2022-02-22 22:54:15 -08:00
parent d7105e7631
commit 454c149898
3 changed files with 32 additions and 6 deletions
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11
bolt/include/bolt/Core/MCPlusBuilder.h
View file

@ -74,9 +74,9 @@ private:
AllocatorIdTy MaxAllocatorId = 0;
/// We encode Index and Value into a 64-bit immediate operand value.
static int64_t encodeAnnotationImm(unsigned Index, int64_t Value) {
assert(Index < 256 && "annotation index max value exceeded");
assert((Value == (Value << 8) >> 8) && "annotation value out of range");
static int64_t encodeAnnotationImm(uint8_t Index, int64_t Value) {
if (LLVM_UNLIKELY(Value != extractAnnotationValue(Value)))
report_fatal_error("annotation value out of range");
Value &= 0xff'ffff'ffff'ffff;
Value |= (int64_t)Index << 56;
@ -85,14 +85,13 @@ private:
}
/// Extract annotation index from immediate operand value.
static unsigned extractAnnotationIndex(int64_t ImmValue) {
static uint8_t extractAnnotationIndex(int64_t ImmValue) {
return ImmValue >> 56;
}
/// Extract annotation value from immediate operand value.
static int64_t extractAnnotationValue(int64_t ImmValue) {
ImmValue &= 0xff'ffff'ffff'ffff;
return (ImmValue << 8) >> 8;
return SignExtend64<56>(ImmValue & 0xff'ffff'ffff'ffffULL);
}
MCInst *getAnnotationInst(const MCInst &Inst) const {

1
bolt/unittests/Core/CMakeLists.txt
View file

@ -3,6 +3,7 @@ set(LLVM_LINK_COMPONENTS
BOLTRewrite
DebugInfoDWARF
Object
MC
${LLVM_TARGETS_TO_BUILD}
)

26
bolt/unittests/Core/MCPlusBuilder.cpp
View file

@ -110,3 +110,29 @@ TEST_P(MCPlusBuilderTester, AliasSmallerAX) {
}
#endif // X86_AVAILABLE
TEST_P(MCPlusBuilderTester, Annotation) {
MCInst Inst;
bool Success = BC->MIB->createTailCall(Inst, BC->Ctx->createNamedTempSymbol(),
BC->Ctx.get());
ASSERT_TRUE(Success);
MCSymbol *LPSymbol = BC->Ctx->createNamedTempSymbol("LP");
uint64_t Value = INT32_MIN;
// Test encodeAnnotationImm using this indirect way
BC->MIB->addEHInfo(Inst, MCPlus::MCLandingPad(LPSymbol, Value));
// Round-trip encoding-decoding check for negative values
Optional<MCPlus::MCLandingPad> EHInfo = BC->MIB->getEHInfo(Inst);
ASSERT_TRUE(EHInfo.hasValue());
MCPlus::MCLandingPad LP = EHInfo.getValue();
uint64_t DecodedValue = LP.second;
ASSERT_EQ(Value, DecodedValue);
// Large int64 should trigger an out of range assertion
Value = 0x1FF'FFFF'FFFF'FFFFULL;
Inst.clear();
Success = BC->MIB->createTailCall(Inst, BC->Ctx->createNamedTempSymbol(),
BC->Ctx.get());
ASSERT_TRUE(Success);
ASSERT_DEATH(BC->MIB->addEHInfo(Inst, MCPlus::MCLandingPad(LPSymbol, Value)),
"annotation value out of range");
}