248a5a20a0
This is the LLVM piece of this work. There is also a clang piece, which adds this metadata to AllocaInst when the source does `__attribute__((no_stack_protector))` on a variable. We already have `__attribute__((no_stack_protector))` on functions, but opting out the whole function might be too heavy a hammer. Instead this allows us to opt out of stack protectors on specific allocations we might have audited an know to be safe, but still allow the function to generate a stack protector if other allocations necessitate it.
56 lines
1.9 KiB
LLVM
56 lines
1.9 KiB
LLVM
; RUN: llc -mtriple=aarch64-apple-darwin < %s -o - | FileCheck %s
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@.str = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
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; CHECK-LABEL: test1:
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; CHECK-NOT: ___stack_chk_guard
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; Function Attrs: noinline nounwind optnone
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define void @test1(ptr noundef %msg) #0 {
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entry:
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%msg.addr = alloca ptr, align 8
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%a = alloca [1000 x i8], align 1, !stack-protector !2
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store ptr %msg, ptr %msg.addr, align 8
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%arraydecay = getelementptr inbounds [1000 x i8], ptr %a, i64 0, i64 0
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%0 = load ptr, ptr %msg.addr, align 8
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%call = call ptr @strcpy(ptr noundef %arraydecay, ptr noundef %0) #3
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%arraydecay1 = getelementptr inbounds [1000 x i8], ptr %a, i64 0, i64 0
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%call2 = call i32 (ptr, ...) @printf(ptr noundef @.str, ptr noundef %arraydecay1)
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ret void
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}
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; CHECK-LABEL: test2:
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; CHECK: ___stack_chk_guard
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; Function Attrs: noinline nounwind optnone
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define void @test2(ptr noundef %msg) #0 {
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entry:
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%msg.addr = alloca ptr, align 8
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%b = alloca [1000 x i8], align 1
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store ptr %msg, ptr %msg.addr, align 8
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%arraydecay = getelementptr inbounds [1000 x i8], ptr %b, i64 0, i64 0
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%0 = load ptr, ptr %msg.addr, align 8
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%call = call ptr @strcpy(ptr noundef %arraydecay, ptr noundef %0) #3
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%arraydecay1 = getelementptr inbounds [1000 x i8], ptr %b, i64 0, i64 0
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%call2 = call i32 (ptr, ...) @printf(ptr noundef @.str, ptr noundef %arraydecay1)
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ret void
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}
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; Function Attrs: nounwind
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declare ptr @strcpy(ptr noundef, ptr noundef) #1
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declare i32 @printf(ptr noundef, ...) #2
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attributes #0 = { noinline nounwind optnone "no-trapping-math"="true" "stack-protector-buffer-size"="8" ssp }
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attributes #1 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
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attributes #2 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
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attributes #3 = { nounwind }
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!llvm.module.flags = !{!0}
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!llvm.ident = !{!1}
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!0 = !{i32 1, !"wchar_size", i32 4}
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!1 = !{!"clang version 22.0.0"}
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!2 = !{i32 0}
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