[llvm] 41860e6 - BPF: Support btf_type_tag attribute
Yonghong Song via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 4 17:02:37 PDT 2021
Author: Yonghong Song
Date: 2021-11-04T17:01:36-07:00
New Revision: 41860e602aaa94556ba996fae7b8baa268e25096
URL: https://github.com/llvm/llvm-project/commit/41860e602aaa94556ba996fae7b8baa268e25096
DIFF: https://github.com/llvm/llvm-project/commit/41860e602aaa94556ba996fae7b8baa268e25096.diff
LOG: BPF: Support btf_type_tag attribute
A new kind BTF_KIND_TYPE_TAG is defined. The tags associated
with a pointer type are emitted in their IR order as modifiers.
For example, for the following declaration:
int __tag1 * __tag1 __tag2 *g;
The BTF type chain will look like
VAR(g) -> __tag1 --> __tag2 -> pointer -> __tag1 -> pointer -> int
In the above "->" means BTF CommonType.Type which indicates
the point-to type.
Differential Revision: https://reviews.llvm.org/D113222
Added:
llvm/test/CodeGen/BPF/BTF/type-tag-var.ll
Modified:
llvm/lib/Target/BPF/BTF.def
llvm/lib/Target/BPF/BTF.h
llvm/lib/Target/BPF/BTFDebug.cpp
llvm/lib/Target/BPF/BTFDebug.h
Removed:
################################################################################
diff --git a/llvm/lib/Target/BPF/BTF.def b/llvm/lib/Target/BPF/BTF.def
index aeb81c6fecaf..0ae4194bc512 100644
--- a/llvm/lib/Target/BPF/BTF.def
+++ b/llvm/lib/Target/BPF/BTF.def
@@ -32,5 +32,6 @@ HANDLE_BTF_KIND(14, VAR)
HANDLE_BTF_KIND(15, DATASEC)
HANDLE_BTF_KIND(16, FLOAT)
HANDLE_BTF_KIND(17, DECL_TAG)
+HANDLE_BTF_KIND(18, TYPE_TAG)
#undef HANDLE_BTF_KIND
diff --git a/llvm/lib/Target/BPF/BTF.h b/llvm/lib/Target/BPF/BTF.h
index 95a64609ae38..e54b97cd49a9 100644
--- a/llvm/lib/Target/BPF/BTF.h
+++ b/llvm/lib/Target/BPF/BTF.h
@@ -113,7 +113,7 @@ struct CommonType {
/// "Size" tells the size of the type it is describing.
///
/// "Type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
- /// FUNC, FUNC_PROTO, VAR and DECL_TAG.
+ /// FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG.
/// "Type" is a type_id referring to another type.
union {
uint32_t Size;
diff --git a/llvm/lib/Target/BPF/BTFDebug.cpp b/llvm/lib/Target/BPF/BTFDebug.cpp
index bbe8eb1071ae..401bdfa47659 100644
--- a/llvm/lib/Target/BPF/BTFDebug.cpp
+++ b/llvm/lib/Target/BPF/BTFDebug.cpp
@@ -408,6 +408,19 @@ void BTFTypeDeclTag::emitType(MCStreamer &OS) {
OS.emitInt32(Info);
}
+BTFTypeTypeTag::BTFTypeTypeTag(uint32_t BaseTypeId, StringRef Tag) : Tag(Tag) {
+ Kind = BTF::BTF_KIND_TYPE_TAG;
+ BTFType.Info = Kind << 24;
+ BTFType.Type = BaseTypeId;
+}
+
+void BTFTypeTypeTag::completeType(BTFDebug &BDebug) {
+ if (IsCompleted)
+ return;
+ IsCompleted = true;
+ BTFType.NameOff = BDebug.addString(Tag);
+}
+
uint32_t BTFStringTable::addString(StringRef S) {
// Check whether the string already exists.
for (auto &OffsetM : OffsetToIdMap) {
@@ -658,9 +671,41 @@ void BTFDebug::visitDerivedType(const DIDerivedType *DTy, uint32_t &TypeId,
}
}
- if (Tag == dwarf::DW_TAG_pointer_type || Tag == dwarf::DW_TAG_typedef ||
- Tag == dwarf::DW_TAG_const_type || Tag == dwarf::DW_TAG_volatile_type ||
- Tag == dwarf::DW_TAG_restrict_type) {
+ if (Tag == dwarf::DW_TAG_pointer_type) {
+ SmallVector<const MDString *, 4> MDStrs;
+ DINodeArray Annots = DTy->getAnnotations();
+ if (Annots) {
+ for (const Metadata *Annotations : Annots->operands()) {
+ const MDNode *MD = cast<MDNode>(Annotations);
+ const MDString *Name = cast<MDString>(MD->getOperand(0));
+ if (!Name->getString().equals("btf_type_tag"))
+ continue;
+ MDStrs.push_back(cast<MDString>(MD->getOperand(1)));
+ }
+ }
+
+ if (MDStrs.size() > 0) {
+ auto TypeEntry = std::make_unique<BTFTypeDerived>(DTy, Tag, false);
+ unsigned TmpTypeId = addType(std::move(TypeEntry));
+ for (unsigned I = MDStrs.size(); I > 0; I--) {
+ const MDString *Value = MDStrs[I - 1];
+ if (I != 1) {
+ auto TypeEntry =
+ std::make_unique<BTFTypeTypeTag>(TmpTypeId, Value->getString());
+ TmpTypeId = addType(std::move(TypeEntry));
+ } else {
+ auto TypeEntry =
+ std::make_unique<BTFTypeTypeTag>(TmpTypeId, Value->getString());
+ TypeId = addType(std::move(TypeEntry), DTy);
+ }
+ }
+ } else {
+ auto TypeEntry = std::make_unique<BTFTypeDerived>(DTy, Tag, false);
+ TypeId = addType(std::move(TypeEntry), DTy);
+ }
+ } else if (Tag == dwarf::DW_TAG_typedef || Tag == dwarf::DW_TAG_const_type ||
+ Tag == dwarf::DW_TAG_volatile_type ||
+ Tag == dwarf::DW_TAG_restrict_type) {
auto TypeEntry = std::make_unique<BTFTypeDerived>(DTy, Tag, false);
TypeId = addType(std::move(TypeEntry), DTy);
if (Tag == dwarf::DW_TAG_typedef)
diff --git a/llvm/lib/Target/BPF/BTFDebug.h b/llvm/lib/Target/BPF/BTFDebug.h
index 9e0203f292b2..69b53f20ab71 100644
--- a/llvm/lib/Target/BPF/BTFDebug.h
+++ b/llvm/lib/Target/BPF/BTFDebug.h
@@ -216,6 +216,14 @@ class BTFTypeDeclTag : public BTFTypeBase {
void emitType(MCStreamer &OS) override;
};
+class BTFTypeTypeTag : public BTFTypeBase {
+ StringRef Tag;
+
+public:
+ BTFTypeTypeTag(uint32_t BaseTypeId, StringRef Tag);
+ void completeType(BTFDebug &BDebug) override;
+};
+
/// String table.
class BTFStringTable {
/// String table size in bytes.
diff --git a/llvm/test/CodeGen/BPF/BTF/type-tag-var.ll b/llvm/test/CodeGen/BPF/BTF/type-tag-var.ll
new file mode 100644
index 000000000000..1acf2c6db83f
--- /dev/null
+++ b/llvm/test/CodeGen/BPF/BTF/type-tag-var.ll
@@ -0,0 +1,63 @@
+; 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:
+; #define __tag1 __attribute__((btf_type_tag("tag1")))
+; #define __tag2 __attribute__((btf_type_tag("tag2")))
+; int __tag1 * __tag1 __tag2 *g;
+; Compilation flag:
+; clang -target bpf -O2 -g -S -emit-llvm test.c
+
+ at g = dso_local local_unnamed_addr global i32** null, align 8, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!12, !13, !14, !15}
+!llvm.ident = !{!16}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 3, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 14.0.0 (https://github.com/llvm/llvm-project.git 077b2e0cf1e97c4d97ca5ceab3ec0192ed11c66e)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "test.c", directory: "/tmp/home/yhs/work/tests/llvm/btf_tag_type")
+!4 = !{!0}
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64, annotations: !10)
+!6 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !7, size: 64, annotations: !8)
+!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!8 = !{!9}
+!9 = !{!"btf_type_tag", !"tag1"}
+!10 = !{!9, !11}
+!11 = !{!"btf_type_tag", !"tag2"}
+
+; CHECK: .long 0 # BTF_KIND_PTR(id = 1)
+; CHECK-NEXT: .long 33554432 # 0x2000000
+; CHECK-NEXT: .long 5
+; CHECK-NEXT: .long 1 # BTF_KIND_TYPE_TAG(id = 2)
+; CHECK-NEXT: .long 301989888 # 0x12000000
+; CHECK-NEXT: .long 1
+; CHECK-NEXT: .long 6 # BTF_KIND_TYPE_TAG(id = 3)
+; CHECK-NEXT: .long 301989888 # 0x12000000
+; CHECK-NEXT: .long 2
+; CHECK-NEXT: .long 0 # BTF_KIND_PTR(id = 4)
+; CHECK-NEXT: .long 33554432 # 0x2000000
+; CHECK-NEXT: .long 6
+; CHECK-NEXT: .long 6 # BTF_KIND_TYPE_TAG(id = 5)
+; CHECK-NEXT: .long 301989888 # 0x12000000
+; CHECK-NEXT: .long 4
+; CHECK-NEXT: .long 11 # BTF_KIND_INT(id = 6)
+; CHECK-NEXT: .long 16777216 # 0x1000000
+; CHECK-NEXT: .long 4
+; CHECK-NEXT: .long 16777248 # 0x1000020
+; CHECK-NEXT: .long 15 # BTF_KIND_VAR(id = 7)
+; CHECK-NEXT: .long 234881024 # 0xe000000
+; CHECK-NEXT: .long 3
+; CHECK-NEXT: .long 1
+
+; CHECK: .ascii "tag2" # string offset=1
+; CHECK: .ascii "tag1" # string offset=6
+; CHECK: .ascii "int" # string offset=11
+; CHECK: .byte 103 # string offset=15
+
+!12 = !{i32 7, !"Dwarf Version", i32 4}
+!13 = !{i32 2, !"Debug Info Version", i32 3}
+!14 = !{i32 1, !"wchar_size", i32 4}
+!15 = !{i32 7, !"frame-pointer", i32 2}
+!16 = !{!"clang version 14.0.0 (https://github.com/llvm/llvm-project.git 077b2e0cf1e97c4d97ca5ceab3ec0192ed11c66e)"}
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