[lldb] Add SB API to access static constexpr member values

lldb/include/lldb/API/SBTarget.h

@@ -954,6 +954,7 @@ class LLDB_API SBTarget {
   friend class SBSection;
   friend class SBSourceManager;
   friend class SBSymbol;
+  friend class SBTypeStaticField;
   friend class SBValue;
   friend class SBVariablesOptions;
 

lldb/include/lldb/API/SBType.h

@@ -107,6 +107,35 @@ class SBTypeMemberFunction {
   lldb::TypeMemberFunctionImplSP m_opaque_sp;
 };
 
+class LLDB_API SBTypeStaticField {
+public:
+  SBTypeStaticField();
+
+  SBTypeStaticField(const lldb::SBTypeStaticField &rhs);
+  lldb::SBTypeStaticField &operator=(const lldb::SBTypeStaticField &rhs);
+
+  ~SBTypeStaticField();
+
+  explicit operator bool() const;
+
+  bool IsValid() const;
+
+  const char *GetName();
+
+  const char *GetMangledName();
+
+  lldb::SBType GetType();
+
+  lldb::SBValue GetConstantValue(lldb::SBTarget target);
+
+protected:
+  friend class SBType;
+
+  explicit SBTypeStaticField(lldb_private::CompilerDecl decl);
+
+  std::unique_ptr<lldb_private::CompilerDecl> m_opaque_up;
+};
+
 class SBType {
 public:
   SBType();
@@ -182,6 +211,8 @@ class SBType {
 
   lldb::SBTypeMember GetVirtualBaseClassAtIndex(uint32_t idx);
 
+  lldb::SBTypeStaticField GetStaticFieldWithName(const char *name);
+
   lldb::SBTypeEnumMemberList GetEnumMembers();
 
   uint32_t GetNumberOfTemplateArguments();
@@ -242,6 +273,7 @@ class SBType {
   friend class SBTypeNameSpecifier;
   friend class SBTypeMember;
   friend class SBTypeMemberFunction;
+  friend class SBTypeStaticField;
   friend class SBTypeList;
   friend class SBValue;
   friend class SBWatchpoint;

lldb/include/lldb/API/SBValue.h

@@ -426,6 +426,7 @@ class LLDB_API SBValue {
   friend class SBModule;
   friend class SBTarget;
   friend class SBThread;
+  friend class SBTypeStaticField;
   friend class SBTypeSummary;
   friend class SBValueList;
 

lldb/include/lldb/Symbol/CompilerDecl.h

@@ -73,6 +73,9 @@ class CompilerDecl {
 
   CompilerDeclContext GetDeclContext() const;
 
+  // If this decl has a type, return it.
+  CompilerType GetType() const;
+
   // If this decl represents a function, return the return type
   CompilerType GetFunctionReturnType() const;
 
@@ -91,6 +94,10 @@ class CompilerDecl {
   /// the subsequent entry, so the topmost entry is the global namespace.
   std::vector<lldb_private::CompilerContext> GetCompilerContext() const;
 
+  // If decl represents a constant value, return it. Otherwise, return an
+  // invalid/empty Scalar.
+  Scalar GetConstantValue() const;
+
 private:
   TypeSystem *m_type_system = nullptr;
   void *m_opaque_decl = nullptr;

lldb/include/lldb/Symbol/CompilerType.h

@@ -416,6 +416,8 @@ class CompilerType {
   CompilerType GetVirtualBaseClassAtIndex(size_t idx,
                                           uint32_t *bit_offset_ptr) const;
 
+  CompilerDecl GetStaticFieldWithName(llvm::StringRef name) const;
+
   uint32_t GetIndexOfFieldWithName(const char *name,
                                    CompilerType *field_compiler_type = nullptr,
                                    uint64_t *bit_offset_ptr = nullptr,

lldb/include/lldb/Symbol/TypeSystem.h

@@ -27,6 +27,8 @@
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
 #include "lldb/Symbol/Type.h"
+#include "lldb/Utility/Scalar.h"
+#include "lldb/lldb-forward.h"
 #include "lldb/lldb-private.h"
 #include "lldb/lldb-types.h"
 
@@ -110,6 +112,8 @@ class TypeSystem : public PluginInterface,
   virtual std::vector<lldb_private::CompilerContext>
   DeclGetCompilerContext(void *opaque_decl);
 
+  virtual Scalar DeclGetConstantValue(void *opaque_decl) { return Scalar(); }
+
   virtual CompilerType GetTypeForDecl(void *opaque_decl) = 0;
 
   // CompilerDeclContext functions
@@ -339,6 +343,11 @@ class TypeSystem : public PluginInterface,
   GetVirtualBaseClassAtIndex(lldb::opaque_compiler_type_t type, size_t idx,
                              uint32_t *bit_offset_ptr) = 0;
 
+  virtual CompilerDecl GetStaticFieldWithName(lldb::opaque_compiler_type_t type,
+                                              llvm::StringRef name) {
+    return CompilerDecl();
+  }
+
   virtual CompilerType GetChildCompilerTypeAtIndex(
       lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx, size_t idx,
       bool transparent_pointers, bool omit_empty_base_classes,

lldb/source/API/SBType.cpp

@@ -7,16 +7,21 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/API/SBType.h"
+#include "Utils.h"
 #include "lldb/API/SBDefines.h"
 #include "lldb/API/SBModule.h"
 #include "lldb/API/SBStream.h"
 #include "lldb/API/SBTypeEnumMember.h"
 #include "lldb/Core/Mangled.h"
+#include "lldb/Core/ValueObjectConstResult.h"
+#include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerType.h"
 #include "lldb/Symbol/Type.h"
 #include "lldb/Symbol/TypeSystem.h"
 #include "lldb/Utility/ConstString.h"
+#include "lldb/Utility/DataExtractor.h"
 #include "lldb/Utility/Instrumentation.h"
+#include "lldb/Utility/Scalar.h"
 #include "lldb/Utility/Stream.h"
 
 #include "llvm/ADT/APSInt.h"
@@ -325,6 +330,79 @@ lldb::SBTypeMemberFunction SBType::GetMemberFunctionAtIndex(uint32_t idx) {
   return sb_func_type;
 }
 
+SBTypeStaticField::SBTypeStaticField() { LLDB_INSTRUMENT_VA(this); }
+
+SBTypeStaticField::SBTypeStaticField(lldb_private::CompilerDecl decl)
+    : m_opaque_up(decl ? std::make_unique<CompilerDecl>(decl) : nullptr) {}
+
+SBTypeStaticField::SBTypeStaticField(const SBTypeStaticField &rhs) {
+  LLDB_INSTRUMENT_VA(this, rhs);
+
+  m_opaque_up = clone(rhs.m_opaque_up);
+}
+
+SBTypeStaticField &SBTypeStaticField::operator=(const SBTypeStaticField &rhs) {
+  LLDB_INSTRUMENT_VA(this, rhs);
+
+  m_opaque_up = clone(rhs.m_opaque_up);
+  return *this;
+}
+
+SBTypeStaticField::~SBTypeStaticField() { LLDB_INSTRUMENT_VA(this); }
+
+SBTypeStaticField::operator bool() const {
+  LLDB_INSTRUMENT_VA(this);
+
+  return IsValid();
+}
+
+bool SBTypeStaticField::IsValid() const {
+  LLDB_INSTRUMENT_VA(this);
+
+  return m_opaque_up != nullptr;
+}
+
+const char *SBTypeStaticField::GetName() {
+  LLDB_INSTRUMENT_VA(this);
+
+  if (!IsValid())
+    return "";
+  return m_opaque_up->GetName().GetCString();
+}
+
+const char *SBTypeStaticField::GetMangledName() {
+  LLDB_INSTRUMENT_VA(this);
+
+  if (!IsValid())
+    return "";
+  return m_opaque_up->GetMangledName().GetCString();
+}
+
+SBType SBTypeStaticField::GetType() {
+  LLDB_INSTRUMENT_VA(this);
+
+  if (!IsValid())
+    return SBType();
+  return SBType(m_opaque_up->GetType());
+}
+
+SBValue SBTypeStaticField::GetConstantValue(lldb::SBTarget target) {
+  LLDB_INSTRUMENT_VA(this, target);
+
+  if (!IsValid())
+    return SBValue();
+
+  Scalar value = m_opaque_up->GetConstantValue();
+  if (!value.IsValid())
+    return SBValue();
+  DataExtractor data;
+  value.GetData(data);
+  auto value_obj_sp = ValueObjectConstResult::Create(
+      target.GetSP().get(), m_opaque_up->GetType(), m_opaque_up->GetName(),
+      data);
+  return SBValue(std::move(value_obj_sp));
+}
+
 lldb::SBType SBType::GetUnqualifiedType() {
   LLDB_INSTRUMENT_VA(this);
 
@@ -438,6 +516,16 @@ SBTypeMember SBType::GetVirtualBaseClassAtIndex(uint32_t idx) {
   return sb_type_member;
 }
 
+SBTypeStaticField SBType::GetStaticFieldWithName(const char *name) {
+  LLDB_INSTRUMENT_VA(this, name);
+
+  if (!IsValid() || !name)
+    return SBTypeStaticField();
+
+  return SBTypeStaticField(m_opaque_sp->GetCompilerType(/*prefer_dynamic=*/true)
+                               .GetStaticFieldWithName(name));
+}
+
 SBTypeEnumMemberList SBType::GetEnumMembers() {
   LLDB_INSTRUMENT_VA(this);
 

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -9,6 +9,7 @@
 #include "TypeSystemClang.h"
 
 #include "clang/AST/DeclBase.h"
+#include "clang/AST/ExprCXX.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/FormatAdapters.h"
 #include "llvm/Support/FormatVariadic.h"
@@ -1145,6 +1146,8 @@ CompilerType TypeSystemClang::GetTypeForDecl(clang::NamedDecl *decl) {
     return GetTypeForDecl(interface_decl);
   if (clang::TagDecl *tag_decl = llvm::dyn_cast<clang::TagDecl>(decl))
     return GetTypeForDecl(tag_decl);
+  if (clang::ValueDecl *value_decl = llvm::dyn_cast<clang::ValueDecl>(decl))
+    return GetTypeForDecl(value_decl);
   return CompilerType();
 }
 
@@ -1156,6 +1159,10 @@ CompilerType TypeSystemClang::GetTypeForDecl(ObjCInterfaceDecl *decl) {
   return GetType(getASTContext().getObjCInterfaceType(decl));
 }
 
+CompilerType TypeSystemClang::GetTypeForDecl(clang::ValueDecl *value_decl) {
+  return GetType(value_decl->getType());
+}
+
 #pragma mark Structure, Unions, Classes
 
 void TypeSystemClang::SetOwningModule(clang::Decl *decl,
@@ -5900,6 +5907,36 @@ CompilerType TypeSystemClang::GetVirtualBaseClassAtIndex(
   return CompilerType();
 }
 
+CompilerDecl
+TypeSystemClang::GetStaticFieldWithName(lldb::opaque_compiler_type_t type,
+                                        llvm::StringRef name) {
+  clang::QualType qual_type = RemoveWrappingTypes(GetCanonicalQualType(type));
+  switch (qual_type->getTypeClass()) {
+  case clang::Type::Record: {
+    if (!GetCompleteType(type))
+      return CompilerDecl();
+
+    const clang::RecordType *record_type =
+        llvm::cast<clang::RecordType>(qual_type.getTypePtr());
+    const clang::RecordDecl *record_decl = record_type->getDecl();
+
+    clang::DeclarationName decl_name(&getASTContext().Idents.get(name));
+    for (NamedDecl *decl : record_decl->lookup(decl_name)) {
+      auto *var_decl = dyn_cast<clang::VarDecl>(decl);
+      if (!var_decl || var_decl->getStorageClass() != clang::SC_Static)
+        continue;
+
+      return CompilerDecl(this, var_decl);
+    }
+    break;
+  }
+
+  default:
+    break;
+  }
+  return CompilerDecl();
+}
+
 // If a pointer to a pointee type (the clang_type arg) says that it has no
 // children, then we either need to trust it, or override it and return a
 // different result. For example, an "int *" has one child that is an integer,
@@ -9074,6 +9111,21 @@ CompilerType TypeSystemClang::DeclGetFunctionArgumentType(void *opaque_decl,
   return CompilerType();
 }
 
+Scalar TypeSystemClang::DeclGetConstantValue(void *opaque_decl) {
+  clang::Decl *decl = static_cast<clang::Decl *>(opaque_decl);
+  clang::VarDecl *var_decl = llvm::dyn_cast<clang::VarDecl>(decl);
+  if (!var_decl)
+    return Scalar();
+  clang::Expr *init_expr = var_decl->getInit();
+  if (!init_expr)
+    return Scalar();
+  std::optional<llvm::APSInt> value =
+      init_expr->getIntegerConstantExpr(getASTContext());
+  if (!value)
+    return Scalar();
+  return Scalar(*value);
+}
+
 // CompilerDeclContext functions
 
 std::vector<CompilerDecl> TypeSystemClang::DeclContextFindDeclByName(

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h

@@ -22,6 +22,7 @@
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTFwd.h"
+#include "clang/AST/Decl.h"
 #include "clang/AST/TemplateBase.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/TargetInfo.h"
@@ -251,6 +252,8 @@ class TypeSystemClang : public TypeSystem {
 
   CompilerType GetTypeForDecl(clang::ObjCInterfaceDecl *objc_decl);
 
+  CompilerType GetTypeForDecl(clang::ValueDecl *value_decl);
+
   template <typename RecordDeclType>
   CompilerType
   GetTypeForIdentifier(llvm::StringRef type_name,
@@ -559,6 +562,8 @@ class TypeSystemClang : public TypeSystem {
   std::vector<lldb_private::CompilerContext>
   DeclGetCompilerContext(void *opaque_decl) override;
 
+  Scalar DeclGetConstantValue(void *opaque_decl) override;
+
   CompilerType GetTypeForDecl(void *opaque_decl) override;
 
   // CompilerDeclContext override functions
@@ -868,6 +873,9 @@ class TypeSystemClang : public TypeSystem {
                                           size_t idx,
                                           uint32_t *bit_offset_ptr) override;
 
+  CompilerDecl GetStaticFieldWithName(lldb::opaque_compiler_type_t type,
+                                      llvm::StringRef name) override;
+
   static uint32_t GetNumPointeeChildren(clang::QualType type);
 
   CompilerType GetChildCompilerTypeAtIndex(

lldb/source/Symbol/CompilerDecl.cpp

@@ -9,6 +9,7 @@
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
 #include "lldb/Symbol/TypeSystem.h"
+#include "lldb/Utility/Scalar.h"
 
 using namespace lldb_private;
 
@@ -24,6 +25,10 @@ CompilerDeclContext CompilerDecl::GetDeclContext() const {
   return m_type_system->DeclGetDeclContext(m_opaque_decl);
 }
 
+CompilerType CompilerDecl::GetType() const {
+  return m_type_system->GetTypeForDecl(m_opaque_decl);
+}
+
 CompilerType CompilerDecl::GetFunctionReturnType() const {
   return m_type_system->DeclGetFunctionReturnType(m_opaque_decl);
 }
@@ -52,3 +57,7 @@ std::vector<lldb_private::CompilerContext>
 CompilerDecl::GetCompilerContext() const {
   return m_type_system->DeclGetCompilerContext(m_opaque_decl);
 }
+
+Scalar CompilerDecl::GetConstantValue() const {
+  return m_type_system->DeclGetConstantValue(m_opaque_decl);
+}