BPF: rename BTF_KIND_TAG to BTF_KIND_DECL_TAG

[yonghong-song]

Summary

Per discussion in https://reviews.llvm.org/D111199,
the existing btf_tag attribute will be renamed to
btf_decl_tag. This patch updated BTF backend to
use btf_decl_tag attribute name and also
renamed BTF_KIND_TAG to BTF_KIND_DECL_TAG.

[anakryiko]

lgtm

llvm/lib/Target/BPF/BTF.h

struct CommonType {
   uint32_t NameOff;
 
   /// "Info" bits arrangement:
   /// Bits  0-15: vlen (e.g. # of struct's members)
   /// Bits 16-23: unused
   /// Bits 24-27: kind (e.g. int, ptr, array...etc)
   /// Bits 28-30: unused
   /// Bit     31: kind_flag, currently used by
-  ///             struct, union, fwd and tag
+  ///             struct, union, fwd and decl_tag
   uint32_t Info;
 
   /// "Size" is used by INT, ENUM, STRUCT and UNION.
   /// "Size" tells the size of the type it is describing.
   ///
   /// "Type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
-  /// FUNC, FUNC_PROTO, VAR and TAG.
+  /// FUNC, FUNC_PROTO, VAR and DECL_TAG.
   /// "Type" is a type_id referring to another type.
   union {
     uint32_t Size;
     uint32_t Type;
   };
 };
 
 // For some specific BTF_KIND, "struct CommonType" is immediately

llvm/lib/Target/BPF/BTF.def

 HANDLE_BTF_KIND(9, VOLATILE)
 HANDLE_BTF_KIND(10, CONST)
 HANDLE_BTF_KIND(11, RESTRICT)
 HANDLE_BTF_KIND(12, FUNC)
 HANDLE_BTF_KIND(13, FUNC_PROTO)
 HANDLE_BTF_KIND(14, VAR)
 HANDLE_BTF_KIND(15, DATASEC)
 HANDLE_BTF_KIND(16, FLOAT)
-HANDLE_BTF_KIND(17, TAG)
+HANDLE_BTF_KIND(17, DECL_TAG)
 
 #undef HANDLE_BTF_KIND

llvm/lib/Target/BPF/BTFDebug.h

class BTFTypeFloat : public BTFTypeBase {
   StringRef Name;
 
 public:
   BTFTypeFloat(uint32_t SizeInBits, StringRef TypeName);
   void completeType(BTFDebug &BDebug) override;
 };
 
 /// Handle tags.
-class BTFTypeTag : public BTFTypeBase {
+class BTFTypeDeclTag : public BTFTypeBase {
   uint32_t Info;
   StringRef Tag;
 
 public:
-  BTFTypeTag(uint32_t BaseTypeId, int ComponentId, StringRef Tag);
+  BTFTypeDeclTag(uint32_t BaseTypeId, int ComponentId, StringRef Tag);
   uint32_t getSize() override { return BTFTypeBase::getSize() + 4; }
   void completeType(BTFDebug &BDebug) override;
   void emitType(MCStreamer &OS) override;
 };
 
 /// String table.
 class BTFStringTable {
   /// String table size in bytes.

llvm/lib/Target/BPF/BTFDebug.cpp

 void BTFTypeFloat::completeType(BTFDebug &BDebug) {
   if (IsCompleted)
     return;
   IsCompleted = true;
 
   BTFType.NameOff = BDebug.addString(Name);
 }
 
-BTFTypeTag::BTFTypeTag(uint32_t BaseTypeId, int ComponentIdx, StringRef Tag)
+BTFTypeDeclTag::BTFTypeDeclTag(uint32_t BaseTypeId, int ComponentIdx,
+                               StringRef Tag)
     : Tag(Tag) {
-  Kind = BTF::BTF_KIND_TAG;
+  Kind = BTF::BTF_KIND_DECL_TAG;
   BTFType.Info = Kind << 24;
   BTFType.Type = BaseTypeId;
   Info = ComponentIdx;
 }
 
-void BTFTypeTag::completeType(BTFDebug &BDebug) {
+void BTFTypeDeclTag::completeType(BTFDebug &BDebug) {
   if (IsCompleted)
     return;
   IsCompleted = true;
 
   BTFType.NameOff = BDebug.addString(Tag);
 }
 
-void BTFTypeTag::emitType(MCStreamer &OS) {
+void BTFTypeDeclTag::emitType(MCStreamer &OS) {
   BTFTypeBase::emitType(OS);
   OS.emitInt32(Info);
 }
 
 uint32_t BTFStringTable::addString(StringRef S) {
   // Check whether the string already exists.
   for (auto &OffsetM : OffsetToIdMap) {
     if (Table[OffsetM.second] == S)

 void BTFDebug::processAnnotations(DINodeArray Annotations, uint32_t BaseTypeId,
                                   int ComponentIdx) {
   if (!Annotations)
      return;
 
   for (const Metadata *Annotation : Annotations->operands()) {
     const MDNode *MD = cast<MDNode>(Annotation);
     const MDString *Name = cast<MDString>(MD->getOperand(0));
-    if (!Name->getString().equals("btf_tag"))
+    if (!Name->getString().equals("btf_decl_tag"))
       continue;
 
     const MDString *Value = cast<MDString>(MD->getOperand(1));
-    auto TypeEntry = std::make_unique<BTFTypeTag>(BaseTypeId, ComponentIdx,
+    auto TypeEntry = std::make_unique<BTFTypeDeclTag>(BaseTypeId, ComponentIdx,
                                                       Value->getString());
     addType(std::move(TypeEntry));
   }
 }
 
 /// Handle structure/union types.
 void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct,
                                uint32_t &TypeId) {
   const DINodeArray Elements = CTy->getElements();

llvm/test/CodeGen/BPF/BTF/tag-1.ll

 ; 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 code:
-;   #define __tag1 __attribute__((btf_tag("tag1")))
-;   #define __tag2 __attribute__((btf_tag("tag2")))
+;   #define __tag1 __attribute__((btf_decl_tag("tag1")))
+;   #define __tag2 __attribute__((btf_decl_tag("tag2")))
 ;   struct t1 {
 ;     int a1;
 ;     int a2 __tag1 __tag2;
 ;   } __tag1 __tag2;
 ;   struct t1 g1 __tag1 __tag2;
 ; Compilation flag:
 ;   clang -target bpf -O2 -g -S -emit-llvm t.c
 

 !4 = !{}
 !5 = !{!0}
 !6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1", file: !3, line: 3, size: 64, elements: !7, annotations: !11)
 !7 = !{!8, !10}
 !8 = !DIDerivedType(tag: DW_TAG_member, name: "a1", scope: !6, file: !3, line: 4, baseType: !9, size: 32)
 !9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !10 = !DIDerivedType(tag: DW_TAG_member, name: "a2", scope: !6, file: !3, line: 5, baseType: !9, size: 32, offset: 32, annotations: !11)
 !11 = !{!12, !13}
-!12 = !{!"btf_tag", !"tag1"}
-!13 = !{!"btf_tag", !"tag2"}
+!12 = !{!"btf_decl_tag", !"tag1"}
+!13 = !{!"btf_decl_tag", !"tag2"}
 !14 = !{i32 7, !"Dwarf Version", i32 4}
 !15 = !{i32 2, !"Debug Info Version", i32 3}
 !16 = !{i32 1, !"wchar_size", i32 4}
 !17 = !{i32 7, !"frame-pointer", i32 2}
 !18 = !{!"clang version 13.0.0 (https://github.com/llvm/llvm-project.git 825661b8e31d0b29d78178df1e518949dfec9f9a)"}
 
 ; CHECK:             .long   1                               # BTF_KIND_STRUCT(id = 1)
 ; CHECK-NEXT:        .long   67108866                        # 0x4000002
 ; CHECK-NEXT:        .long   8
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   0                               # 0x0
 ; CHECK-NEXT:        .long   7
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   32                              # 0x20
-; CHECK-NEXT:        .long   10                              # BTF_KIND_TAG(id = 2)
+; CHECK-NEXT:        .long   10                              # BTF_KIND_DECL_TAG(id = 2)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   4294967295
-; CHECK-NEXT:        .long   15                              # BTF_KIND_TAG(id = 3)
+; CHECK-NEXT:        .long   15                              # BTF_KIND_DECL_TAG(id = 3)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   4294967295
 ; CHECK-NEXT:        .long   20                              # BTF_KIND_INT(id = 4)
 ; CHECK-NEXT:        .long   16777216                        # 0x1000000
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   16777248                        # 0x1000020
-; CHECK-NEXT:        .long   10                              # BTF_KIND_TAG(id = 5)
+; CHECK-NEXT:        .long   10                              # BTF_KIND_DECL_TAG(id = 5)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   1
-; CHECK-NEXT:        .long   15                              # BTF_KIND_TAG(id = 6)
+; CHECK-NEXT:        .long   15                              # BTF_KIND_DECL_TAG(id = 6)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   24                              # BTF_KIND_VAR(id = 7)
 ; CHECK-NEXT:        .long   234881024                       # 0xe000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   1
-; CHECK-NEXT:        .long   10                              # BTF_KIND_TAG(id = 8)
+; CHECK-NEXT:        .long   10                              # BTF_KIND_DECL_TAG(id = 8)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   7
 ; CHECK-NEXT:        .long   4294967295
-; CHECK-NEXT:        .long   15                              # BTF_KIND_TAG(id = 9)
+; CHECK-NEXT:        .long   15                              # BTF_KIND_DECL_TAG(id = 9)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   7
 ; CHECK-NEXT:        .long   4294967295
 
 ; CHECK:             .ascii  "t1"                            # string offset=1
 ; CHECK:             .ascii  "a1"                            # string offset=4
 ; CHECK:             .ascii  "a2"                            # string offset=7
 ; CHECK:             .ascii  "tag1"                          # string offset=10
 ; CHECK:             .ascii  "tag2"                          # string offset=15
 ; CHECK:             .ascii  "int"                           # string offset=20
 ; CHECK:             .ascii  "g1"                            # string offset=24

llvm/test/CodeGen/BPF/BTF/tag-2.ll

 ; 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 code:
-;   #define __tag1 __attribute__((btf_tag("tag1")))
-;   #define __tag2 __attribute__((btf_tag("tag2")))
+;   #define __tag1 __attribute__((btf_decl_tag("tag1")))
+;   #define __tag2 __attribute__((btf_decl_tag("tag2")))
 ;   extern int bar(int a1, int a2) __tag1 __tag2;
 ;   int __tag1 foo(int arg1, int *arg2 __tag1) {
 ; ;   return arg1 + *arg2 + bar(arg1, arg1 + 1);
 ;   }
 ; Compilation flag:
 ;   clang -target bpf -O2 -g -S -emit-llvm t.c
 
 ; Function Attrs: nounwind

 !9 = !DISubroutineType(types: !10)
 !10 = !{!11, !11, !12}
 !11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !11, size: 64)
 !13 = !{!14, !15}
 !14 = !DILocalVariable(name: "arg1", arg: 1, scope: !8, file: !1, line: 4, type: !11)
 !15 = !DILocalVariable(name: "arg2", arg: 2, scope: !8, file: !1, line: 4, type: !12, annotations: !16)
 !16 = !{!17}
-!17 = !{!"btf_tag", !"tag1"}
+!17 = !{!"btf_decl_tag", !"tag1"}
 !18 = !DILocation(line: 0, scope: !8)
 !19 = !DILocation(line: 5, column: 17, scope: !8)
 !20 = !{!21, !21, i64 0}
 !21 = !{!"int", !22, i64 0}
 !22 = !{!"omnipotent char", !23, i64 0}
 !23 = !{!"Simple C/C++ TBAA"}
 !24 = !DILocation(line: 5, column: 15, scope: !8)
 !25 = !DILocation(line: 5, column: 40, scope: !8)
 !26 = !DILocation(line: 5, column: 25, scope: !8)
 !27 = !DILocation(line: 5, column: 23, scope: !8)
 !28 = !DILocation(line: 5, column: 3, scope: !8)
 !29 = !DISubprogram(name: "bar", scope: !1, file: !1, line: 3, type: !30, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2, annotations: !32)
 !30 = !DISubroutineType(types: !31)
 !31 = !{!11, !11, !11}
 !32 = !{!17, !33}
-!33 = !{!"btf_tag", !"tag2"}
+!33 = !{!"btf_decl_tag", !"tag2"}
 
 ; CHECK:             .long   1                               # BTF_KIND_INT(id = 1)
 ; CHECK-NEXT:        .long   16777216                        # 0x1000000
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   16777248                        # 0x1000020
 ; CHECK-NEXT:        .long   0                               # BTF_KIND_PTR(id = 2)
 ; CHECK-NEXT:        .long   33554432                        # 0x2000000
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   0                               # BTF_KIND_FUNC_PROTO(id = 3)
 ; CHECK-NEXT:        .long   218103810                       # 0xd000002
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   5
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   10
 ; CHECK-NEXT:        .long   2
 ; CHECK-NEXT:        .long   15                              # BTF_KIND_FUNC(id = 4)
 ; CHECK-NEXT:        .long   201326593                       # 0xc000001
 ; CHECK-NEXT:        .long   3
-; CHECK-NEXT:        .long   19                              # BTF_KIND_TAG(id = 5)
+; CHECK-NEXT:        .long   19                              # BTF_KIND_DECL_TAG(id = 5)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   1
-; CHECK-NEXT:        .long   19                              # BTF_KIND_TAG(id = 6)
+; CHECK-NEXT:        .long   19                              # BTF_KIND_DECL_TAG(id = 6)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   4
 ; CHECK-NEXT:        .long   4294967295
 ; CHECK-NEXT:        .long   0                               # BTF_KIND_FUNC_PROTO(id = 7)
 ; CHECK-NEXT:        .long   218103810                       # 0xd000002
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   0
 ; CHECK-NEXT:        .long   1
 ; CHECK-NEXT:        .long   72                              # BTF_KIND_FUNC(id = 8)
 ; CHECK-NEXT:        .long   201326594                       # 0xc000002
 ; CHECK-NEXT:        .long   7
-; CHECK-NEXT:        .long   19                              # BTF_KIND_TAG(id = 9)
+; CHECK-NEXT:        .long   19                              # BTF_KIND_DECL_TAG(id = 9)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   8
 ; CHECK-NEXT:        .long   4294967295
-; CHECK-NEXT:        .long   76                              # BTF_KIND_TAG(id = 10)
+; CHECK-NEXT:        .long   76                              # BTF_KIND_DECL_TAG(id = 10)
 ; CHECK-NEXT:        .long   285212672                       # 0x11000000
 ; CHECK-NEXT:        .long   8
 ; CHECK-NEXT:        .long   4294967295
 
 ; CHECK:             .ascii  "int"                           # string offset=1
 ; CHECK:             .ascii  "arg1"                          # string offset=5
 ; CHECK:             .ascii  "arg2"                          # string offset=10
 ; CHECK:             .ascii  "foo"                           # string offset=15
 ; CHECK:             .ascii  "tag1"                          # string offset=19
 ; CHECK:             .ascii  "bar"                           # string offset=72
 ; CHECK:             .ascii  "tag2"                          # string offset=76