Revert "[BPF] Fix a BTF type pruning bug"

This reverts commit 19149538e9a9fce91bcdf70b69dc6defc9e8a533.

This fix was accidentally committed.

2 files changed, 7 insertions, 110 deletions

diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp
index 166b62bd6226..d536aed1d211 100644
--- a/llvm/lib/Target/BPF/BTFDebug.cpp
+++ b/llvm/lib/Target/BPF/BTFDebug.cpp
@@ -773,31 +773,15 @@ void BTFDebug::visitTypeEntry(const DIType *Ty, uint32_t &TypeId,
     // already defined, we should keep moving to eventually
     // bring in types for "struct t". Otherwise, the "struct s2"
     // definition won't be correct.
-    //
-    // In the above, we have following debuginfo:
-    //  {ptr, struct_member} ->  typedef -> struct
-    // and BTF type for 'typedef' is generated while 'struct' may
-    // be in FixUp. But let us generalize the above to handle
-    //  {different types} -> [various derived types]+ -> another type.
-    // For example,
-    //  {func_param, struct_member} -> const -> ptr -> volatile -> struct
-    // We will traverse const/ptr/volatile which already have corresponding
-    // BTF types and generate type for 'struct' which might be in Fixup
-    // state.
     if (Ty && (!CheckPointer || !SeenPointer)) {
       if (const auto *DTy = dyn_cast<DIDerivedType>(Ty)) {
-        while (DTy) {
-          const DIType *BaseTy = DTy->getBaseType();
-          if (!BaseTy)
-            break;
-
-          if (DIToIdMap.find(BaseTy) != DIToIdMap.end()) {
-            DTy = dyn_cast<DIDerivedType>(BaseTy);
-          } else {
-            uint32_t TmpTypeId;
-            visitTypeEntry(BaseTy, TmpTypeId, CheckPointer, SeenPointer);
-            break;
-          }
+        unsigned Tag = DTy->getTag();
+        if (Tag == dwarf::DW_TAG_typedef || Tag == dwarf::DW_TAG_const_type ||
+            Tag == dwarf::DW_TAG_volatile_type ||
+            Tag == dwarf::DW_TAG_restrict_type) {
+          uint32_t TmpTypeId;
+          visitTypeEntry(DTy->getBaseType(), TmpTypeId, CheckPointer,
+                         SeenPointer);
         }
       }
     }
diff --git a/llvm/test/CodeGen/BPF/BTF/pruning-multi-derived-type.ll b/llvm/test/CodeGen/BPF/BTF/pruning-multi-derived-type.ll
deleted file mode 100644
index 63c864fd0e3a..000000000000
--- a/llvm/test/CodeGen/BPF/BTF/pruning-multi-derived-type.ll
+++ /dev/null
@@ -1,87 +0,0 @@
-; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
-; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
-; Source:
-;   struct t1 {
-;     int a;
-;   };
-;   struct t2 {
-;     const struct t1 * const a;
-;   };
-;   int foo(struct t2 *arg) { return 0; }
-;   int bar(const struct t1 * const arg) { return 0; }
-; Compilation flags:
-;   clang -target bpf -O2 -g -S -emit-llvm t.c
-
-%struct.t2 = type { %struct.t1* }
-%struct.t1 = type { i32 }
-
-; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
-define dso_local i32 @foo(%struct.t2* nocapture noundef readnone %arg) local_unnamed_addr #0 !dbg !7 {
-entry:
-  call void @llvm.dbg.value(metadata %struct.t2* %arg, metadata !22, metadata !DIExpression()), !dbg !23
-  ret i32 0, !dbg !24
-}
-
-; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
-define dso_local i32 @bar(%struct.t1* nocapture noundef readnone %arg) local_unnamed_addr #0 !dbg !25 {
-entry:
-  call void @llvm.dbg.value(metadata %struct.t1* %arg, metadata !29, metadata !DIExpression()), !dbg !30
-  ret i32 0, !dbg !31
-}
-
-; CHECK:             .long   10                              # BTF_KIND_INT(id = 7)
-; CHECK-NEXT:        .long   16777216                        # 0x1000000
-; CHECK-NEXT:        .long   4
-; CHECK-NEXT:        .long   16777248                        # 0x1000020
-
-; CHECK:             .long   69                              # BTF_KIND_STRUCT(id = 9)
-; CHECK-NEXT:        .long   67108865                        # 0x4000001
-; CHECK-NEXT:        .long   4
-; CHECK-NEXT:        .long   4
-; CHECK-NEXT:        .long   7
-
-; CHECK:             .byte   97                              # string offset=4
-; CHECK:             .ascii  "t1"                            # string offset=69
-
-; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
-declare void @llvm.dbg.value(metadata, metadata, metadata) #1
-
-attributes #0 = { mustprogress nofree norecurse nosync nounwind readnone willreturn "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
-attributes #1 = { nofree nosync nounwind readnone speculatable willreturn }
-
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!2, !3, !4, !5}
-!llvm.ident = !{!6}
-
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 15.0.0 (https://github.com/llvm/llvm-project.git c34c8afcb85ae9142d0f783bb899c464e8bd2356)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
-!1 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/llvm/btf_ptr", checksumkind: CSK_MD5, checksum: "d43a0541e830263021772349589e47a5")
-!2 = !{i32 7, !"Dwarf Version", i32 5}
-!3 = !{i32 2, !"Debug Info Version", i32 3}
-!4 = !{i32 1, !"wchar_size", i32 4}
-!5 = !{i32 7, !"frame-pointer", i32 2}
-!6 = !{!"clang version 15.0.0 (https://github.com/llvm/llvm-project.git c34c8afcb85ae9142d0f783bb899c464e8bd2356)"}
-!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 7, type: !8, scopeLine: 7, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !21)
-!8 = !DISubroutineType(types: !9)
-!9 = !{!10, !11}
-!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!11 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !12, size: 64)
-!12 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t2", file: !1, line: 4, size: 64, elements: !13)
-!13 = !{!14}
-!14 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !12, file: !1, line: 5, baseType: !15, size: 64)
-!15 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !16)
-!16 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !17, size: 64)
-!17 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !18)
-!18 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1", file: !1, line: 1, size: 32, elements: !19)
-!19 = !{!20}
-!20 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !18, file: !1, line: 2, baseType: !10, size: 32)
-!21 = !{!22}
-!22 = !DILocalVariable(name: "arg", arg: 1, scope: !7, file: !1, line: 7, type: !11)
-!23 = !DILocation(line: 0, scope: !7)
-!24 = !DILocation(line: 7, column: 27, scope: !7)
-!25 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 8, type: !26, scopeLine: 8, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !28)
-!26 = !DISubroutineType(types: !27)
-!27 = !{!10, !15}
-!28 = !{!29}
-!29 = !DILocalVariable(name: "arg", arg: 1, scope: !25, file: !1, line: 8, type: !15)
-!30 = !DILocation(line: 0, scope: !25)
-!31 = !DILocation(line: 8, column: 40, scope: !25)