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[ASAN] Do not consider alignment during object size calculations #109120

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Merged
merged 1 commit into from
Sep 19, 2024
Merged

[ASAN] Do not consider alignment during object size calculations #109120

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4 changes: 1 addition & 3 deletions llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3057,9 +3057,7 @@ bool AddressSanitizer::instrumentFunction(Function &F,
OperandsToInstrument.size() + IntrinToInstrument.size() >
(unsigned)InstrumentationWithCallsThreshold);
const DataLayout &DL = F.getDataLayout();
ObjectSizeOpts ObjSizeOpts;
ObjSizeOpts.RoundToAlign = true;
ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(), ObjSizeOpts);
ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext());

// Instrument.
int NumInstrumented = 0;
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21 changes: 21 additions & 0 deletions llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ target triple = "x86_64-unknown-linux-gnu"
; indexed with constants in-bounds. But instrument all other cases.

@GlobSt = global [10 x i32] zeroinitializer, align 16 ; static initializer
@GlobStAlignInBounds = global [10 x i8] zeroinitializer, align 16 ; static initializer
@GlobDy = global [10 x i32] zeroinitializer, align 16, sanitize_address_dyninit ; dynamic initializer
@GlobEx = external global [10 x i32] , align 16 ; extern initializer

Expand Down Expand Up @@ -49,6 +50,26 @@ entry:
; CHECK: ret i32
}

; GlobStAlignInBount is accessed with out of bounds index, but in bounds of allocated area (because of alignemnt)
define i8 @AccessGlobStAlignInBounds_0_11() sanitize_address {
entry:
%0 = load i8, ptr getelementptr inbounds ([10 x i8], ptr @GlobStAlignInBounds, i64 0, i64 11), align 1
ret i8 %0
; CHECK-LABEL: define i8 @AccessGlobStAlignInBounds_0_11
; CHECK: __asan_report
; CHECK: ret i8
}

; GlobStAlignInBount is accessed with in-bound index
define i8 @AccessGlobStAlignInBounds_0_9() sanitize_address {
entry:
%0 = load i8, ptr getelementptr inbounds ([10 x i8], ptr @GlobStAlignInBounds, i64 0, i64 9), align 1
ret i8 %0
; CHECK-LABEL: define i8 @AccessGlobStAlignInBounds_0_9
; CHECK-NOT: __asan_report
; CHECK: ret i8
}

; GlobDy is declared with dynamic initializer -- can't optimize.
define i32 @AccessGlobDy_0_2() sanitize_address {
entry:
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