types: buf: Fix buffer size calculation

18ca7ff ("semantic: Push metadata headroom calculation into type") made the mistake of thinking SizedType constructor takes size in bits. In reality it is in bytes. This closes bpftrace#3280.
danobi · Jun 27, 2024 · e4b4ebb · e4b4ebb
1 parent e357b49
commit e4b4ebb
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,6  17,8 @@ and this project adheres to
 #### Deprecated
 #### Removed
 #### Fixed
 - Fix incorrect buf() size calculation which could lead to verifier errors
   - [#3281](https://github.com/bpftrace/bpftrace/pull/3281)
 #### Security
 #### Docs
 #### Tools

diff --git a/src/types.cpp b/src/types.cpp
@@ -435,8  435,8 @@ SizedType CreateKSym()
 
 SizedType CreateBuffer(size_t size)
 {
-  auto metadata_headroom_bits = sizeof(AsyncEvent::Buf) * 8;
-  return SizedType(Type::buffer, size   metadata_headroom_bits);
   auto metadata_headroom_bytes = sizeof(AsyncEvent::Buf);
   return SizedType(Type::buffer, size   metadata_headroom_bytes);
 }
 
 SizedType CreateTimestamp()

diff --git a/tests/codegen/llvm/call_buf_implicit_size.ll b/tests/codegen/llvm/call_buf_implicit_size.ll
@@ -95,10  95,10 @@ attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 !18 = !DIBasicType(name: "int64", size: 64, encoding: DW_ATE_signed)
 !19 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !20, size: 64, offset: 192)
 !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !21, size: 64)
-!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 384, elements: !23)
 !21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 160, elements: !23)
 !22 = !DIBasicType(name: "int8", size: 8, encoding: DW_ATE_signed)
 !23 = !{!24}
-!24 = !DISubrange(count: 48, lowerBound: 0)
 !24 = !DISubrange(count: 20, lowerBound: 0)
 !25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
 !26 = distinct !DIGlobalVariable(name: "ringbuf", linkageName: "global", scope: !2, file: !2, type: !27, isLocal: false, isDefinition: true)
 !27 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 128, elements: !28)

diff --git a/tests/codegen/llvm/call_buf_size_literal.ll b/tests/codegen/llvm/call_buf_size_literal.ll
@@ -91,10  91,10 @@ attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 !18 = !DIBasicType(name: "int64", size: 64, encoding: DW_ATE_signed)
 !19 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !20, size: 64, offset: 192)
 !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !21, size: 64)
-!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 264, elements: !23)
 !21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 40, elements: !23)
 !22 = !DIBasicType(name: "int8", size: 8, encoding: DW_ATE_signed)
 !23 = !{!24}
-!24 = !DISubrange(count: 33, lowerBound: 0)
 !24 = !DISubrange(count: 5, lowerBound: 0)
 !25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
 !26 = distinct !DIGlobalVariable(name: "ringbuf", linkageName: "global", scope: !2, file: !2, type: !27, isLocal: false, isDefinition: true)
 !27 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 128, elements: !28)

diff --git a/tests/codegen/llvm/call_buf_size_nonliteral.ll b/tests/codegen/llvm/call_buf_size_nonliteral.ll
@@ -13,12  13,12 @@ target triple = "bpf-pc-linux"
 @AT_x = dso_local global %"struct map_t" zeroinitializer, section ".maps", !dbg !0
 @ringbuf = dso_local global %"struct map_t.0" zeroinitializer, section ".maps", !dbg !25
 @str_buffer = dso_local global %"struct map_t.1" zeroinitializer, section ".maps", !dbg !39
-@event_loss_counter = dso_local global %"struct map_t.2" zeroinitializer, section ".maps", !dbg !57
 @event_loss_counter = dso_local global %"struct map_t.2" zeroinitializer, section ".maps", !dbg !52
 
 ; Function Attrs: nounwind
 declare i64 @llvm.bpf.pseudo(i64 %0, i64 %1) #0
 
-define i64 @kprobe_f_1(i8* %0) section "s_kprobe_f_1" !dbg !71 {
 define i64 @kprobe_f_1(i8* %0) section "s_kprobe_f_1" !dbg !66 {
 entry:
   %"@x_key" = alloca i64, align 8
   %lookup_str_key = alloca i32, align 4
@@ -73,8  73,8 @@ attributes #0 = { nounwind }
 attributes #1 = { argmemonly nofree nosync nounwind willreturn }
 attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 
-!llvm.dbg.cu = !{!67}
-!llvm.module.flags = !{!70}
 !llvm.dbg.cu = !{!62}
 !llvm.module.flags = !{!65}
 
 !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
 !1 = distinct !DIGlobalVariable(name: "AT_x", linkageName: "global", scope: !2, file: !2, type: !3, isLocal: false, isDefinition: true)
@@ -97,10  97,10 @@ attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 !18 = !DIBasicType(name: "int64", size: 64, encoding: DW_ATE_signed)
 !19 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !20, size: 64, offset: 192)
 !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !21, size: 64)
-!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 736, elements: !23)
 !21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 512, elements: !23)
 !22 = !DIBasicType(name: "int8", size: 8, encoding: DW_ATE_signed)
 !23 = !{!24}
-!24 = !DISubrange(count: 92, lowerBound: 0)
 !24 = !DISubrange(count: 64, lowerBound: 0)
 !25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
 !26 = distinct !DIGlobalVariable(name: "ringbuf", linkageName: "global", scope: !2, file: !2, type: !27, isLocal: false, isDefinition: true)
 !27 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 128, elements: !28)
@@ -118,7  118,7 @@ attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 !39 = !DIGlobalVariableExpression(var: !40, expr: !DIExpression())
 !40 = distinct !DIGlobalVariable(name: "str_buffer", linkageName: "global", scope: !2, file: !2, type: !41, isLocal: false, isDefinition: true)
 !41 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 256, elements: !42)
-!42 = !{!43, !48, !49, !52}
 !42 = !{!43, !48, !49, !19}
 !43 = !DIDerivedType(tag: DW_TAG_member, name: "type", scope: !2, file: !2, baseType: !44, size: 64)
 !44 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !45, size: 64)
 !45 = !DICompositeType(tag: DW_TAG_array_type, baseType: !8, size: 192, elements: !46)
@@ -128,28  128,23 @@ attributes #2 = { argmemonly nofree nosync nounwind willreturn writeonly }
 !49 = !DIDerivedType(tag: DW_TAG_member, name: "key", scope: !2, file: !2, baseType: !50, size: 64, offset: 128)
 !50 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !51, size: 64)
 !51 = !DIBasicType(name: "int32", size: 32, encoding: DW_ATE_signed)
-!52 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !53, size: 64, offset: 192)
-!53 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !54, size: 64)
-!54 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 512, elements: !55)
-!55 = !{!56}
-!56 = !DISubrange(count: 64, lowerBound: 0)
-!57 = !DIGlobalVariableExpression(var: !58, expr: !DIExpression())
-!58 = distinct !DIGlobalVariable(name: "event_loss_counter", linkageName: "global", scope: !2, file: !2, type: !59, isLocal: false, isDefinition: true)
-!59 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 256, elements: !60)
-!60 = !{!61, !48, !49, !66}
-!61 = !DIDerivedType(tag: DW_TAG_member, name: "type", scope: !2, file: !2, baseType: !62, size: 64)
-!62 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !63, size: 64)
-!63 = !DICompositeType(tag: DW_TAG_array_type, baseType: !8, size: 64, elements: !64)
-!64 = !{!65}
-!65 = !DISubrange(count: 2, lowerBound: 0)
-!66 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !17, size: 64, offset: 192)
-!67 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer: "bpftrace", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !68, globals: !69)
-!68 = !{}
-!69 = !{!0, !25, !39, !57}
-!70 = !{i32 2, !"Debug Info Version", i32 3}
-!71 = distinct !DISubprogram(name: "kprobe_f_1", linkageName: "kprobe_f_1", scope: !2, file: !2, type: !72, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !67, retainedNodes: !75)
-!72 = !DISubroutineType(types: !73)
-!73 = !{!18, !74}
-!74 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !22, size: 64)
-!75 = !{!76}
-!76 = !DILocalVariable(name: "ctx", arg: 1, scope: !71, file: !2, type: !74)
 !52 = !DIGlobalVariableExpression(var: !53, expr: !DIExpression())
 !53 = distinct !DIGlobalVariable(name: "event_loss_counter", linkageName: "global", scope: !2, file: !2, type: !54, isLocal: false, isDefinition: true)
 !54 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 256, elements: !55)
 !55 = !{!56, !48, !49, !61}
 !56 = !DIDerivedType(tag: DW_TAG_member, name: "type", scope: !2, file: !2, baseType: !57, size: 64)
 !57 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !58, size: 64)
 !58 = !DICompositeType(tag: DW_TAG_array_type, baseType: !8, size: 64, elements: !59)
 !59 = !{!60}
 !60 = !DISubrange(count: 2, lowerBound: 0)
 !61 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !17, size: 64, offset: 192)
 !62 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer: "bpftrace", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !63, globals: !64)
 !63 = !{}
 !64 = !{!0, !25, !39, !52}
 !65 = !{i32 2, !"Debug Info Version", i32 3}
 !66 = distinct !DISubprogram(name: "kprobe_f_1", linkageName: "kprobe_f_1", scope: !2, file: !2, type: !67, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !62, retainedNodes: !70)
 !67 = !DISubroutineType(types: !68)
 !68 = !{!18, !69}
 !69 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !22, size: 64)
 !70 = !{!71}
 !71 = !DILocalVariable(name: "ctx", arg: 1, scope: !66, file: !2, type: !69)