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transform: track 0-index GEPs

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It appears that LLVM is turning bitcasts into 0-index GEPs.
This caused stuff to not be tracked, resulting in use-after-free issues.
This solution is sub-optimal, but is the most reasonable solution I could come up with without redesigning the stack slots pass.
This commit is contained in:
Jaden Weiss
2020-07-15 18:15:27 -04:00
committed by Ayke
parent ae5b297d59
commit 19e0f4709e
3 changed files with 61 additions and 13 deletions
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transform/testdata/gc-stackslots.ll
Vendored
+11
View File
@@ -84,3 +84,14 @@ loop:
end:
ret i8* %next.x
}
declare [32 x i8]* @arrayAlloc()
define void @testGEPBitcast() {
%arr = call [32 x i8]* @arrayAlloc()
%arr.bitcast = getelementptr [32 x i8], [32 x i8]* %arr, i32 0, i32 0
call void @runtime.trackPointer(i8* %arr.bitcast)
%other = call i8* @runtime.alloc(i32 1)
call void @runtime.trackPointer(i8* %other)
ret void
}
transform/testdata/gc-stackslots.out.ll
Vendored
+32 -9
View File
@@ -30,24 +30,26 @@ define i8* @needsStackSlots() {
}
define i8* @needsStackSlots2() {
%gc.stackobject = alloca { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }
store { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* } { %runtime.stackChainObject* null, i32 4, i8* null, i8* null, i8* null, i8* null }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject
%gc.stackobject = alloca { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }
store { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* } { %runtime.stackChainObject* null, i32 5, i8* null, i8* null, i8* null, i8* null, i8* null }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject
%1 = load %runtime.stackChainObject*, %runtime.stackChainObject** @runtime.stackChainStart
%2 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 0
%2 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 0
store %runtime.stackChainObject* %1, %runtime.stackChainObject** %2
%3 = bitcast { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject to %runtime.stackChainObject*
%3 = bitcast { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject to %runtime.stackChainObject*
store %runtime.stackChainObject* %3, %runtime.stackChainObject** @runtime.stackChainStart
%ptr1 = call i8* @getPointer()
%4 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 4
%4 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 4
store i8* %ptr1, i8** %4
%5 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 3
%5 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 3
store i8* %ptr1, i8** %5
%6 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 2
%6 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 2
store i8* %ptr1, i8** %6
%ptr2 = getelementptr i8, i8* @someGlobal, i32 0
%7 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 5
store i8* %ptr2, i8** %7
%unused = call i8* @runtime.alloc(i32 4)
%7 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 5
store i8* %unused, i8** %7
%8 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8*, i8*, i8*, i8* }* %gc.stackobject, i32 0, i32 6
store i8* %unused, i8** %8
store %runtime.stackChainObject* %1, %runtime.stackChainObject** @runtime.stackChainStart
ret i8* %ptr1
}
@@ -112,3 +114,24 @@ end: ; preds = %loop
store %runtime.stackChainObject* %0, %runtime.stackChainObject** @runtime.stackChainStart
ret i8* %next.x
}
declare [32 x i8]* @arrayAlloc()
define void @testGEPBitcast() {
%gc.stackobject = alloca { %runtime.stackChainObject*, i32, i8*, i8* }
store { %runtime.stackChainObject*, i32, i8*, i8* } { %runtime.stackChainObject* null, i32 2, i8* null, i8* null }, { %runtime.stackChainObject*, i32, i8*, i8* }* %gc.stackobject
%1 = load %runtime.stackChainObject*, %runtime.stackChainObject** @runtime.stackChainStart
%2 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8* }* %gc.stackobject, i32 0, i32 0
store %runtime.stackChainObject* %1, %runtime.stackChainObject** %2
%3 = bitcast { %runtime.stackChainObject*, i32, i8*, i8* }* %gc.stackobject to %runtime.stackChainObject*
store %runtime.stackChainObject* %3, %runtime.stackChainObject** @runtime.stackChainStart
%arr = call [32 x i8]* @arrayAlloc()
%arr.bitcast = getelementptr [32 x i8], [32 x i8]* %arr, i32 0, i32 0
%4 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8* }* %gc.stackobject, i32 0, i32 2
store i8* %arr.bitcast, i8** %4
%other = call i8* @runtime.alloc(i32 1)
%5 = getelementptr { %runtime.stackChainObject*, i32, i8*, i8* }, { %runtime.stackChainObject*, i32, i8*, i8* }* %gc.stackobject, i32 0, i32 3
store i8* %other, i8** %5
store %runtime.stackChainObject* %1, %runtime.stackChainObject** @runtime.stackChainStart
ret void
}