afd20587f9
Fix https://github.com/llvm/llvm-project/issues/63579 ``` % cat a.c void foo() {} % clang --target=arm-none-eabi -mthumb -mno-unaligned-access -fsanitize=kcfi a.c -S -o - | grep p2align .p2align 1 % clang --target=armv6m-none-eabi -fsanitize=function a.c -S -o - | grep p2align .p2align 1 ``` Ensure that -fsanitize={function,kcfi} instrumented functions are aligned by at least 4, so that loading the type hash before the function label will not cause a misaligned access. This is especially important for -mno-unaligned-access configurations that don't set `setMinFunctionAlignment` to 4 or greater. With this patch, the generated assembly for the examples above will contain `.p2align 2` before the type hash. If `__attribute__((aligned(N)))` or `-falign-functions=N` is specified, the larger alignment will be used. Reviewed By: simon_tatham, samitolvanen Differential Revision: https://reviews.llvm.org/D154125
59 lines
1.6 KiB
LLVM
59 lines
1.6 KiB
LLVM
; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,NOC
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; RUN: llc -mtriple=riscv64 -mattr=+c -verify-machineinstrs < %s | FileCheck %s --check-prefixes=CHECK,C
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;; The alignment is at least 4 to avoid unaligned type hash loads when this
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;; instrumented function is indirectly called.
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; CHECK-LABEL: .globl f1
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; CHECK: .p2align 2
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; CHECK-NOT: nop
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; CHECK: .word 12345678
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; CHECK-LABEL: f1:
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define void @f1(ptr noundef %x) !kcfi_type !1 {
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; CHECK: lw t1, -4(a0)
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call void %x() [ "kcfi"(i32 12345678) ]
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ret void
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}
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; CHECK-LABEL: .globl f2
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; NOC: .p2align 2
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; C: .p2align 1
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; CHECK-NOT: .word
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; CHECK-NOT: nop
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; CHECK-LABEL: f2:
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define void @f2(ptr noundef %x) {
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; CHECK: lw t1, -4(a0)
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call void %x() [ "kcfi"(i32 12345678) ]
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ret void
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}
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; CHECK-LABEL: .globl f3
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; CHECK: .p2align 2
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; CHECK: .word 12345678
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; CHECK-COUNT-11: nop
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; CHECK-LABEL: f3:
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define void @f3(ptr noundef %x) #0 !kcfi_type !1 {
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; NOC: lw t1, -48(a0)
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; C: lw t1, -26(a0)
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call void %x() [ "kcfi"(i32 12345678) ]
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ret void
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}
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; CHECK-LABEL: .globl f4
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; NOC: .p2align 2
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; C: .p2align 1
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; CHECK-NOT: .word
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; CHECK-COUNT-11: nop
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; CHECK-LABEL: f4:
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define void @f4(ptr noundef %x) #0 {
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; NOC: lw t1, -48(a0)
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; C: lw t1, -26(a0)
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call void %x() [ "kcfi"(i32 12345678) ]
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ret void
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}
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attributes #0 = { "patchable-function-prefix"="11" }
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!llvm.module.flags = !{!0}
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!0 = !{i32 4, !"kcfi", i32 1}
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!1 = !{i32 12345678}
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