1; RUN: opt -passes=bpf-preserve-static-offset -mtriple=bpf-pc-linux -S -o - %s 2>&1 | FileCheck %s 2; 3; If load offset is not a constant bpf-preserve-static-offset should report a 4; 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 with 26; CHECK-SAME: preserve_static_offset might be rejected by BPF verifier 27 28%struct.foo = type { [7 x i32] } 29 30; Function Attrs: nounwind 31define 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 !8 34 %a = getelementptr inbounds %struct.foo, ptr %0, i32 0, i32 0, !dbg !8 35 %arrayidx = getelementptr inbounds [7 x i32], ptr %a, i64 0, i64 %i, !dbg !9 36 %1 = load i32, ptr %arrayidx, align 4, !dbg !9, !tbaa !10 37 call void @consume(i32 noundef %1), !dbg !14 38 ret void, !dbg !15 39} 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, !dbg 43; CHECK-NEXT: %[[arrayidx:.*]] = getelementptr inbounds [7 x i32], ptr %[[a]], i64 0, i64 %[[i]], !dbg 44; CHECK-NEXT: %[[v5:.*]] = load i32, ptr %[[arrayidx]], align 4, !dbg {{.*}}, !tbaa 45; CHECK-NEXT: call void @consume(i32 noundef %[[v5]]), !dbg 46 47declare void @consume(i32 noundef) #1 48 49; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) 50declare ptr @llvm.preserve.static.offset(ptr readnone) #2 51 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