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1; RUN: opt -passes=bpf-preserve-static-offset -mtriple=bpf-pc-linux -S -o - %s 2>&1 | FileCheck %s2;3; If load offset is not a constant bpf-preserve-static-offset should report a4; warning and remove preserve.static.offset call.5;6; Source:7; #define __ctx __attribute__((preserve_static_offset))8; 9; struct foo {10; int a[7];11; } __ctx;12; 13; extern void consume(int);14; 15; void bar(struct foo *p, unsigned long i) {16; consume(p->a[i]);17; }18;19; Compilation flag:20; clang -cc1 -O2 -debug-info-kind=line-tables-only -triple bpf \21; -S -emit-llvm -disable-llvm-passes -o - \22; | opt -passes=function(sroa) -S -o -23 24; CHECK: warning: some-file.c:10:11: in function bar void (ptr, i64):25; CHECK-SAME: Non-constant offset in access to a field of a type marked with26; CHECK-SAME: preserve_static_offset might be rejected by BPF verifier27 28%struct.foo = type { [7 x i32] }29 30; Function Attrs: nounwind31define dso_local void @bar(ptr noundef %p, i64 noundef %i) #0 !dbg !5 {32entry:33 %0 = call ptr @llvm.preserve.static.offset(ptr %p), !dbg !834 %a = getelementptr inbounds %struct.foo, ptr %0, i32 0, i32 0, !dbg !835 %arrayidx = getelementptr inbounds [7 x i32], ptr %a, i64 0, i64 %i, !dbg !936 %1 = load i32, ptr %arrayidx, align 4, !dbg !9, !tbaa !1037 call void @consume(i32 noundef %1), !dbg !1438 ret void, !dbg !1539}40 41; CHECK: define dso_local void @bar(ptr noundef %[[p:.*]], i64 noundef %[[i:.*]])42; CHECK: %[[a:.*]] = getelementptr inbounds %struct.foo, ptr %[[p]], i32 0, i32 0, !dbg43; CHECK-NEXT: %[[arrayidx:.*]] = getelementptr inbounds [7 x i32], ptr %[[a]], i64 0, i64 %[[i]], !dbg44; CHECK-NEXT: %[[v5:.*]] = load i32, ptr %[[arrayidx]], align 4, !dbg {{.*}}, !tbaa45; CHECK-NEXT: call void @consume(i32 noundef %[[v5]]), !dbg46 47declare void @consume(i32 noundef) #148 49; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)50declare ptr @llvm.preserve.static.offset(ptr readnone) #251 52attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" }53attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" }54attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }55 56!llvm.dbg.cu = !{!0}57!llvm.module.flags = !{!2, !3}58!llvm.ident = !{!4}59 60!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, splitDebugInlining: false, nameTableKind: None)61!1 = !DIFile(filename: "some-file.c", directory: "/some/dir/")62!2 = !{i32 2, !"Debug Info Version", i32 3}63!3 = !{i32 1, !"wchar_size", i32 4}64!4 = !{!"clang"}65!5 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 9, type: !6, scopeLine: 9, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)66!6 = !DISubroutineType(types: !7)67!7 = !{}68!8 = !DILocation(line: 10, column: 14, scope: !5)69!9 = !DILocation(line: 10, column: 11, scope: !5)70!10 = !{!11, !11, i64 0}71!11 = !{!"int", !12, i64 0}72!12 = !{!"omnipotent char", !13, i64 0}73!13 = !{!"Simple C/C++ TBAA"}74!14 = !DILocation(line: 10, column: 3, scope: !5)75!15 = !DILocation(line: 11, column: 1, scope: !5)76