74 lines
2.6 KiB
LLVM
74 lines
2.6 KiB
LLVM
; RUN: opt -passes=bpf-preserve-static-offset -mtriple=bpf-pc-linux -S -o - %s | FileCheck %s
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;
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; Check that bpf-preserve-static-offset folds chain of GEP instructions.
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; The GEP chain in this example has unexpected shape and thus is
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; folded as i8 access.
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;
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; Source (IR modified by hand):
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; #define __ctx __attribute__((preserve_static_offset))
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;
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; struct foo {
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; char a[2];
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; };
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;
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; struct bar {
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; char a;
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; struct foo b;
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; } __ctx;
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;
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; extern void consume(char);
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;
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; void buz(struct bar *p) {
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; consume((&p->b)[1].a[1]);
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; }
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;
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; Compilation flag:
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; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \
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; | opt -passes=function(sroa) -S -o -
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;
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; Modified to remove 'inbounds' from one of the GEP instructions.
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%struct.bar = type { i8, %struct.foo }
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%struct.foo = type { [2 x i8] }
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; Function Attrs: nounwind
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define dso_local void @buz(ptr noundef %p) #0 {
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entry:
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%0 = call ptr @llvm.preserve.static.offset(ptr %p)
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%b = getelementptr inbounds %struct.bar, ptr %0, i32 0, i32 1
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%arrayidx = getelementptr inbounds %struct.foo, ptr %b, i64 1
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; ^^^^^
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; folded as i8 access because of this index
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%a = getelementptr %struct.foo, ptr %arrayidx, i32 0, i32 0
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%arrayidx1 = getelementptr inbounds [2 x i8], ptr %a, i64 0, i64 1
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%1 = load i8, ptr %arrayidx1, align 1, !tbaa !2
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call void @consume(i8 noundef signext %1)
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ret void
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}
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; CHECK: %[[v1:.*]] = call i8 (ptr, i1, i8, i8, i8, i1, ...)
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; CHECK-SAME: @llvm.bpf.getelementptr.and.load.i8
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; CHECK-SAME: (ptr readonly elementtype(i8) %{{[^,]+}},
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; CHECK-SAME: i1 false, i8 0, i8 1, i8 0, i1 false, i64 immarg 4)
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; ^^^^^^^^ ^^^^^^^^^^^^
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; not inbounds ---' |
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; offset from 'struct bar' start -------------'
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; CHECK-NEXT: call void @consume(i8 noundef signext %[[v1]])
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declare void @consume(i8 noundef signext) #1
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; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
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declare ptr @llvm.preserve.static.offset(ptr readnone) #2
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attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
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attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
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attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
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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"}
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!2 = !{!3, !3, i64 0}
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!3 = !{!"omnipotent char", !4, i64 0}
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!4 = !{!"Simple C/C++ TBAA"}
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