Expose dynamic sizes and offsets via DIBuilder

tromey · tromey · commit f43c0a154d40 · 2025-06-25T07:32:43.000-06:00
This adds some new DIBuilder methods to expose the new dynamic size
and offset functionality.
diff --git a/llvm/include/llvm/IR/DIBuilder.h b/llvm/include/llvm/IR/DIBuilder.h
@@ -367,6 +367,22 @@ namespace llvm {
                                               uint32_t VBPtrOffset,
                                               DINode::DIFlags Flags);
 
+    /// Create debugging information entry for a member.
+    /// \param Scope        Member scope.
+    /// \param Name         Member name.
+    /// \param File         File where this member is defined.
+    /// \param LineNo       Line number.
+    /// \param SizeInBits   Member size.
+    /// \param AlignInBits  Member alignment.
+    /// \param OffsetInBits Member offset.
+    /// \param Flags        Flags to encode member attribute, e.g. private
+    /// \param Ty           Parent type.
+    /// \param Annotations  Member annotations.
+    LLVM_ABI DIDerivedType *createMemberType(
+        DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNo,
+        Metadata *SizeInBits, uint32_t AlignInBits, Metadata *OffsetInBits,
+        DINode::DIFlags Flags, DIType *Ty, DINodeArray Annotations = nullptr);
+
     /// Create debugging information entry for a member.
     /// \param Scope        Member scope.
     /// \param Name         Member name.
@@ -419,6 +435,23 @@ namespace llvm {
                                                     Constant *Discriminant,
                                                     DIType *Ty);
 
+    /// Create debugging information entry for a bit field member.
+    /// \param Scope               Member scope.
+    /// \param Name                Member name.
+    /// \param File                File where this member is defined.
+    /// \param LineNo              Line number.
+    /// \param SizeInBits          Member size.
+    /// \param OffsetInBits        Member offset.
+    /// \param StorageOffsetInBits Member storage offset.
+    /// \param Flags               Flags to encode member attribute.
+    /// \param Ty                  Parent type.
+    /// \param Annotations         Member annotations.
+    LLVM_ABI DIDerivedType *createBitFieldMemberType(
+        DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNo,
+        Metadata *SizeInBits, Metadata *OffsetInBits,
+        uint64_t StorageOffsetInBits, DINode::DIFlags Flags, DIType *Ty,
+        DINodeArray Annotations = nullptr);
+
     /// Create debugging information entry for a bit field member.
     /// \param Scope               Member scope.
     /// \param Name                Member name.
@@ -510,6 +543,29 @@ namespace llvm {
         unsigned RunTimeLang = 0, DIType *VTableHolder = nullptr,
         MDNode *TemplateParms = nullptr, StringRef UniqueIdentifier = "");
 
+    /// Create debugging information entry for a struct.
+    /// \param Scope        Scope in which this struct is defined.
+    /// \param Name         Struct name.
+    /// \param File         File where this member is defined.
+    /// \param LineNumber   Line number.
+    /// \param SizeInBits   Member size.
+    /// \param AlignInBits  Member alignment.
+    /// \param Flags        Flags to encode member attribute, e.g. private
+    /// \param Elements     Struct elements.
+    /// \param RunTimeLang  Optional parameter, Objective-C runtime version.
+    /// \param UniqueIdentifier A unique identifier for the struct.
+    /// \param Specification The type that this type completes. This is used by
+    /// Swift to represent generic types.
+    /// \param NumExtraInhabitants The number of extra inhabitants of the type.
+    /// An extra inhabitant is a bit pattern that does not represent a valid
+    /// value for instances of a given type. This is used by the Swift language.
+    LLVM_ABI DICompositeType *createStructType(
+        DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
+        Metadata *SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
+        DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang = 0,
+        DIType *VTableHolder = nullptr, StringRef UniqueIdentifier = "",
+        DIType *Specification = nullptr, uint32_t NumExtraInhabitants = 0);
+
     /// Create debugging information entry for a struct.
     /// \param Scope        Scope in which this struct is defined.
     /// \param Name         Struct name.
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
@@ -428,6 +428,16 @@ DIDerivedType *DIBuilder::createMemberType(
                             std::nullopt, Flags, nullptr, Annotations);
 }
 
+DIDerivedType *DIBuilder::createMemberType(
+    DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
+    Metadata *SizeInBits, uint32_t AlignInBits, Metadata *OffsetInBits,
+    DINode::DIFlags Flags, DIType *Ty, DINodeArray Annotations) {
+  return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
+                            LineNumber, getNonCompileUnitScope(Scope), Ty,
+                            SizeInBits, AlignInBits, OffsetInBits, std::nullopt,
+                            std::nullopt, Flags, nullptr, Annotations);
+}
+
 static ConstantAsMetadata *getConstantOrNull(Constant *C) {
   if (C)
     return ConstantAsMetadata::get(C);
@@ -461,6 +471,20 @@ DIDerivedType *DIBuilder::createVariantMemberType(DIScope *Scope,
                                  DINode::FlagZero, V);
 }
 
+DIDerivedType *DIBuilder::createBitFieldMemberType(
+    DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
+    Metadata *SizeInBits, Metadata *OffsetInBits, uint64_t StorageOffsetInBits,
+    DINode::DIFlags Flags, DIType *Ty, DINodeArray Annotations) {
+  Flags |= DINode::FlagBitField;
+  return DIDerivedType::get(
+      VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
+      getNonCompileUnitScope(Scope), Ty, SizeInBits, /*AlignInBits=*/0,
+      OffsetInBits, std::nullopt, std::nullopt, Flags,
+      ConstantAsMetadata::get(ConstantInt::get(IntegerType::get(VMContext, 64),
+                                               StorageOffsetInBits)),
+      Annotations);
+}
+
 DIDerivedType *DIBuilder::createBitFieldMemberType(
     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
@@ -565,6 +589,22 @@ DICompositeType *DIBuilder::createClassType(
   return R;
 }
 
+DICompositeType *DIBuilder::createStructType(
+    DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
+    Metadata *SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
+    DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang,
+    DIType *VTableHolder, StringRef UniqueIdentifier, DIType *Specification,
+    uint32_t NumExtraInhabitants) {
+  auto *R = DICompositeType::get(
+      VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
+      getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits, 0,
+      Flags, Elements, RunTimeLang, /*EnumKind=*/std::nullopt, VTableHolder,
+      nullptr, UniqueIdentifier, nullptr, nullptr, nullptr, nullptr, nullptr,
+      nullptr, Specification, NumExtraInhabitants);
+  trackIfUnresolved(R);
+  return R;
+}
+
 DICompositeType *DIBuilder::createStructType(
     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
diff --git a/llvm/unittests/IR/DebugInfoTest.cpp b/llvm/unittests/IR/DebugInfoTest.cpp
@@ -1301,4 +1301,33 @@ TEST(DIBuilder, CompositeTypes) {
   EXPECT_EQ(Enum->getTag(), dwarf::DW_TAG_enumeration_type);
 }
 
+TEST(DIBuilder, DynamicOffsetAndSize) {
+  LLVMContext Ctx;
+  auto M = std::make_unique<Module>("MyModule", Ctx);
+  DIBuilder DIB(*M);
+  DIScope *Scope = DISubprogram::getDistinct(
+      Ctx, nullptr, "", "", nullptr, 0, nullptr, 0, nullptr, 0, 0,
+      DINode::FlagZero, DISubprogram::SPFlagZero, nullptr);
+  DIFile *F = DIB.createFile("main.adb", "/");
+
+  DIVariable *Len = DIB.createAutoVariable(Scope, "length", F, 0, nullptr,
+                                           false, DINode::FlagZero, 0);
+
+  DICompositeType *Struct = DIB.createStructType(
+      Scope, "some_record", F, 18, Len, 8, DINode::FlagZero, nullptr, {});
+  EXPECT_EQ(Struct->getTag(), dwarf::DW_TAG_structure_type);
+
+  SmallVector<uint64_t, 4> ops;
+  ops.push_back(llvm::dwarf::DW_OP_push_object_address);
+  DIExpression::appendOffset(ops, 3);
+  ops.push_back(llvm::dwarf::DW_OP_deref);
+  DIExpression *Expr = DIB.createExpression(ops);
+
+  DIDerivedType *Field = DIB.createMemberType(Scope, "field", F, 23, Len, 0,
+                                              Expr, DINode::FlagZero, Struct);
+
+  EXPECT_EQ(Field->getRawOffsetInBits(), Expr);
+  EXPECT_EQ(Field->getRawSizeInBits(), Len);
+}
+
 } // end namespace
