[PATCH] D97986: BPF: permit type modifiers for __builtin_btf_type_id() relocation

[Yonghong Song via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG9c0274cdeae9: BPF: permit type modifiers for __builtin_btf_type_id() relocation (authored by yonghong-song).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97986/new/

https://reviews.llvm.org/D97986

Files:
  llvm/lib/Target/BPF/BPFPreserveDIType.cpp
  llvm/test/CodeGen/BPF/BTF/builtin-btf-type-id-2.ll


Index: llvm/test/CodeGen/BPF/BTF/builtin-btf-type-id-2.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/BPF/BTF/builtin-btf-type-id-2.ll
@@ -0,0 +1,73 @@
+; RUN: opt -O2 -mtriple=bpf-pc-linux -S -o %t1 %s
+; RUN: llc -filetype=asm -o - %t1 | FileCheck -check-prefixes=CHECK %s
+; RUN: llc -mattr=+alu32 -filetype=asm -o - %t1 | FileCheck -check-prefixes=CHECK %s
+; Source code:
+;   struct s {
+;     int a;
+;   };
+;   int test(void) {
+;     return __builtin_btf_type_id(*(const struct s *)0, 1);
+;   }
+; Compilation flag:
+;   clang -target bpf -O2 -g -S -emit-llvm -Xclang -disable-llvm-passes test.c
+
+; Function Attrs: nounwind
+define dso_local i32 @test() #0 !dbg !7 {
+entry:
+  %0 = call i64 @llvm.bpf.btf.type.id(i32 0, i64 1), !dbg !11, !llvm.preserve.access.index !12
+  %conv = trunc i64 %0 to i32, !dbg !11
+  ret i32 %conv, !dbg !16
+}
+
+; CHECK:             .long   1                               # BTF_KIND_INT(id = 2)
+; CHECK-NEXT:        .long   16777216                        # 0x1000000
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   16777248                        # 0x1000020
+
+; CHECK:             .long   16                              # BTF_KIND_STRUCT(id = 4)
+; CHECK-NEXT:        .long   67108865                        # 0x4000001
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   18
+; CHECK-NEXT:        .long   2
+
+; CHECK:             .ascii  "int"                           # string offset=1
+; CHECK:             .ascii  ".text"                         # string offset=10
+; CHECK:             .byte   115                             # string offset=16
+; CHECK:             .byte   97                              # string offset=18
+; CHECK:             .byte   48                              # string offset=20
+
+; CHECK:             .long   16                              # FieldReloc
+; CHECK-NEXT:        .long   10                              # Field reloc section string offset=10
+; CHECK-NEXT:        .long   1
+; CHECK-NEXT:        .long   .Ltmp{{[0-9]+}}
+; CHECK-NEXT:        .long   4
+; CHECK-NEXT:        .long   20
+; CHECK-NEXT:        .long   7
+
+; Function Attrs: nounwind readnone
+declare i64 @llvm.bpf.btf.type.id(i32, i64) #1
+
+attributes #0 = { nounwind "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 13.0.0 (https://github.com/llvm/llvm-project.git 9783e2098800b954c55ae598a1ce5c4b93444fc0)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/bpf/test")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 13.0.0 (https://github.com/llvm/llvm-project.git 9783e2098800b954c55ae598a1ce5c4b93444fc0)"}
+!7 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 4, type: !8, scopeLine: 4, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DILocation(line: 5, column: 10, scope: !7)
+!12 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !13)
+!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "s", file: !1, line: 1, size: 32, elements: !14)
+!14 = !{!15}
+!15 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !13, file: !1, line: 2, baseType: !10, size: 32)
+!16 = !DILocation(line: 5, column: 3, scope: !7)
Index: llvm/lib/Target/BPF/BPFPreserveDIType.cpp
===================================================================
--- llvm/lib/Target/BPF/BPFPreserveDIType.cpp
+++ llvm/lib/Target/BPF/BPFPreserveDIType.cpp
@@ -85,8 +85,17 @@
     } else {
       Reloc = BPFCoreSharedInfo::BTF_TYPE_ID_REMOTE;
       DIType *Ty = cast<DIType>(MD);
+      while (auto *DTy = dyn_cast<DIDerivedType>(Ty)) {
+        unsigned Tag = DTy->getTag();
+        if (Tag != dwarf::DW_TAG_const_type &&
+            Tag != dwarf::DW_TAG_volatile_type)
+          break;
+        Ty = DTy->getBaseType();
+      }
+
       if (Ty->getName().empty())
         report_fatal_error("Empty type name for BTF_TYPE_ID_REMOTE reloc");
+      MD = Ty;
     }
 
     BasicBlock *BB = Call->getParent();


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