68 lines
2.3 KiB
LLVM
68 lines
2.3 KiB
LLVM
; RUN: opt -O2 -mtriple=bpf-pc-linux -S -o - %s | FileCheck %s
|
|
;
|
|
; Check that bpf-preserve-static-offset folds chain of GEP instructions.
|
|
; The GEP chain in this example has type mismatch and thus is
|
|
; folded as i8 access.
|
|
;
|
|
; Source:
|
|
; #define __ctx __attribute__((preserve_static_offset))
|
|
;
|
|
; struct foo {
|
|
; char aa;
|
|
; char bb;
|
|
; };
|
|
;
|
|
; struct bar {
|
|
; char a;
|
|
; struct foo b;
|
|
; } __ctx;
|
|
;
|
|
; void buz(struct bar *p) {
|
|
; ((struct foo *)(((char*)&p->b) + 1))->bb = 42;
|
|
; }
|
|
;
|
|
; Compilation flag:
|
|
; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \
|
|
; | opt -passes=function(sroa) -S -o -
|
|
|
|
%struct.bar = type { i8, %struct.foo }
|
|
%struct.foo = type { i8, i8 }
|
|
|
|
; Function Attrs: nounwind
|
|
define dso_local void @buz(ptr noundef %p) #0 {
|
|
entry:
|
|
%0 = call ptr @llvm.preserve.static.offset(ptr %p)
|
|
%b = getelementptr inbounds %struct.bar, ptr %0, i32 0, i32 1
|
|
%add.ptr = getelementptr inbounds i8, ptr %b, i64 1
|
|
; ~~
|
|
; these types do not match, thus GEP chain is folded as an offset
|
|
; ~~~~~~~~~~~
|
|
%bb = getelementptr inbounds %struct.foo, ptr %add.ptr, i32 0, i32 1
|
|
store i8 42, ptr %bb, align 1, !tbaa !2
|
|
ret void
|
|
}
|
|
|
|
; CHECK: define dso_local void @buz(ptr nocapture noundef writeonly %[[p:.*]])
|
|
; CHECK: tail call void (i8, ptr, i1, i8, i8, i8, i1, ...)
|
|
; CHECK-SAME: @llvm.bpf.getelementptr.and.store.i8
|
|
; CHECK-SAME: (i8 42,
|
|
; CHECK-SAME: ptr writeonly elementtype(i8) %[[p]],
|
|
; CHECK-SAME: i1 false, i8 0, i8 1, i8 0, i1 true, i64 immarg 3)
|
|
; CHECK-SAME: #[[v2:.*]], !tbaa ![[v3:.*]]
|
|
; CHECK: attributes #[[v2]] = { memory(argmem: write) }
|
|
|
|
; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
|
|
declare ptr @llvm.preserve.static.offset(ptr readnone) #1
|
|
|
|
attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
|
|
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
|
|
|
|
!llvm.module.flags = !{!0}
|
|
!llvm.ident = !{!1}
|
|
|
|
!0 = !{i32 1, !"wchar_size", i32 4}
|
|
!1 = !{!"clang"}
|
|
!2 = !{!3, !4, i64 1}
|
|
!3 = !{!"foo", !4, i64 0, !4, i64 1}
|
|
!4 = !{!"omnipotent char", !5, i64 0}
|
|
!5 = !{!"Simple C/C++ TBAA"}
|