================
@@ -0,0 +1,469 @@
+//===-- RPCCommon.cpp 
-----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM 
Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RPCCommon.h"
+
+#include "clang/AST/AST.h"
+#include "clang/AST/Attr.h"
+#include "clang/AST/Attrs.inc"
+#include "clang/AST/DeclBase.h"
+#include "clang/AST/Mangle.h"
+#include "clang/Lex/Lexer.h"
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cstring>
+#include <iostream>
+
+using namespace clang;
+
+// We intentionally do not generate some classes because they are currently
+// inconvenient, they aren't really used by most consumers, or we're not sure
+// why they exist.
+static constexpr llvm::StringRef DisallowedClasses[] = {
+    "SBCommunication", // This class is pretty much unused by consumers, so we
+                       // skip it.
+    "SBInputReader",   // This class is pretty much unused by consumers, so we
+                       // skip it.
+    "SBCommandPluginInterface", // This class uses virtual functions, and the 
SB
+                                // API should not have those, so we skip this
+                                // class.
+    "SBCommand", // There's nothing too difficult about this one, but many of
+                 // its methods take a SBCommandPluginInterface pointer so
+                 // there's no reason to support this.
+};
+
+// NOTE: In lldb-rpc-gen, we use mangled names when we need to work with
+// functions. We do this because we support many functions that have overloads,
+// and mangled names have no ambiguity which makes it easier to keep track of.
+// This is also possible since the LLDB SB API is stable.
+
+// We intentionally avoid generating certain methods either because they are
+// difficult to support correctly or they aren't really used much from C++.
+// NOTE: These methods are marked as deprecated using LLDB_DEPRECATED.
+// Normally this macro defines to the deprecated annotation, but this
+// functionality is removed in SBDefines.h when generating SWIG bindings which
+// we use for testing. Because of this, there is no annotation for the tool to
+// pick up on so this list will be used while we have this restriction in
+// SBDefines.h.
+static constexpr llvm::StringRef DisallowedMethods[] = {
+    // The threading functionality in SBHostOS is deprecated and thus we do not
+    // generate them. It would be ideal to add the annotations to the methods
+    // and then support not generating deprecated methods. However, without
+    // annotations the generator generates most things correctly. This one is
+    // problematic because it returns a pointer to an "opaque" structure
+    // (thread_t) that is not `void *`, so special casing it is more effort 
than
+    // it's worth.
+    "_ZN4lldb8SBHostOS10ThreadJoinEP17_opaque_pthread_tPPvPNS_7SBErrorE",
+    "_ZN4lldb8SBHostOS12ThreadCancelEP17_opaque_pthread_tPNS_7SBErrorE",
+    "_ZN4lldb8SBHostOS12ThreadCreateEPKcPFPvS3_ES3_PNS_7SBErrorE",
+    "_ZN4lldb8SBHostOS12ThreadDetachEP17_opaque_pthread_tPNS_7SBErrorE",
+    "_ZN4lldb8SBHostOS13ThreadCreatedEPKc",
+};
+
+static constexpr llvm::StringRef ClassesWithoutDefaultCtor[] = {
+    "SBHostOS",
+    "SBReproducer",
+};
+
+static constexpr llvm::StringRef ClassesWithoutCopyOperations[] = {
+    "SBHostOS",
+    "SBReproducer",
+    "SBStream",
+    "SBProgress",
+};
+
+// These classes inherit from rpc::ObjectRef directly (as opposed to
+// rpc::LocalObjectRef). Changing them from ObjectRef to LocalObjectRef is ABI
+// breaking, so we preserve that compatibility here.
+//
+// lldb-rpc-gen emits classes as LocalObjectRefs by default.
+//
+// FIXME: Does it matter which one it emits by default?
+static constexpr llvm::StringRef ClassesThatInheritFromObjectRef[] = {
+    "SBAddress",
+    "SBBreakpointName",
+    "SBCommandInterpreter",
+    "SBCommandReturnObject",
+    "SBError",
+    "SBExecutionContext",
+    "SBExpressionOptions",
+    "SBFileSpec",
+    "SBFileSpecList",
+    "SBFormat",
+    "SBFunction",
+    "SBHistoricalFrame",
+    "SBHistoricalLineEntry",
+    "SBHistoricalLineEntryList",
+    "SBLineEntry",
+    "SBStream",
+    "SBStringList",
+    "SBStructuredData",
+    "SBSymbolContext",
+    "SBSymbolContextList",
+    "SBTypeMember",
+    "SBTypeSummaryOptions",
+    "SBValueList",
+};
+
+QualType lldb_rpc_gen::GetUnderlyingType(QualType T) {
+  QualType UnderlyingType;
+  if (T->isPointerType())
+    UnderlyingType = T->getPointeeType();
+  else if (T->isReferenceType())
+    UnderlyingType = T.getNonReferenceType();
+  else
+    UnderlyingType = T;
+
+  return UnderlyingType;
+}
+
+QualType lldb_rpc_gen::GetUnqualifiedUnderlyingType(QualType T) {
+  return GetUnderlyingType(T).getUnqualifiedType();
+}
+
+std::string lldb_rpc_gen::GetMangledName(ASTContext &Context,
+                                         CXXMethodDecl *MDecl) {
+  std::string Mangled;
+  llvm::raw_string_ostream MangledStream(Mangled);
+
+  GlobalDecl GDecl;
+  if (const auto *CtorDecl = dyn_cast<CXXConstructorDecl>(MDecl))
+    GDecl = GlobalDecl(CtorDecl, Ctor_Complete);
+  else if (const auto *DtorDecl = dyn_cast<CXXDestructorDecl>(MDecl))
+    GDecl = GlobalDecl(DtorDecl, Dtor_Deleting);
+  else
+    GDecl = GlobalDecl(MDecl);
+
+  MangleContext *MC = Context.createMangleContext();
+  MC->mangleName(GDecl, MangledStream);
+  return Mangled;
+}
+
+static auto CheckTypeForLLDBPrivate = [](const Type *Ty) {};
+bool lldb_rpc_gen::TypeIsFromLLDBPrivate(QualType T) {
+  auto CheckTypeForLLDBPrivate = [](const Type *Ty) {
+    if (!Ty)
+      return false;
+    const auto *CXXRDecl = Ty->getAsCXXRecordDecl();
+    if (!CXXRDecl)
+      return false;
+    const auto *NSDecl =
+        llvm::dyn_cast<NamespaceDecl>(CXXRDecl->getDeclContext());
+    if (!NSDecl)
+      return false;
+    return NSDecl->getName() == "lldb_private";
+  };
+
+  // First, get the underlying type (remove qualifications and strip off any
+  // pointers/references). Then we'll need to desugar this type. This will
+  // remove things like typedefs, so instead of seeing "lldb::DebuggerSP" we'll
+  // actually see something like "std::shared_ptr<lldb_private::Debugger>".
+  QualType UnqualifiedUnderlyingType = GetUnqualifiedUnderlyingType(T);
+  const Type *DesugaredType =
+      UnqualifiedUnderlyingType->getUnqualifiedDesugaredType();
+  assert(DesugaredType && "DesugaredType from a valid Type is nullptr!");
+
+  // Check the type itself.
+  if (CheckTypeForLLDBPrivate(DesugaredType))
+    return true;
+
+  // If that didn't work, it's possible that the type has a template argument
+  // that is an lldb_private type.
+  if (const auto *TemplateSDecl =
+          llvm::dyn_cast_or_null<ClassTemplateSpecializationDecl>(
+              DesugaredType->getAsCXXRecordDecl())) {
+    for (const TemplateArgument &TA :
+         TemplateSDecl->getTemplateArgs().asArray()) {
+      if (TA.getKind() != TemplateArgument::Type)
+        continue;
+      if (CheckTypeForLLDBPrivate(TA.getAsType().getTypePtr()))
+        return true;
+    }
+  }
+  return false;
+}
+
+bool lldb_rpc_gen::TypeIsSBClass(QualType T) {
+  QualType UnqualifiedUnderlyingType = GetUnqualifiedUnderlyingType(T);
+  const auto *CXXRDecl = UnqualifiedUnderlyingType->getAsCXXRecordDecl();
+  if (!CXXRDecl)
+    return false; // SB Classes are always C++ classes
+
+  return CXXRDecl->getName().starts_with("SB");
+}
+
+bool lldb_rpc_gen::TypeIsConstCharPtr(QualType T) {
+  if (!T->isPointerType())
+    return false;
+
+  QualType UnderlyingType = T->getPointeeType();
+  if (!UnderlyingType.isConstQualified())
+    return false;
+
+  // NOTE: We should be able to do `UnderlyingType->isCharType` but that will
+  // return true for `const uint8_t *` since that is effectively an unsigned
+  // char pointer. We currently do not support pointers other than `const char
+  // *` and `const char **`.
+  return UnderlyingType->isSpecificBuiltinType(BuiltinType::Char_S) ||
+         UnderlyingType->isSpecificBuiltinType(BuiltinType::SChar);
+}
+
+bool lldb_rpc_gen::TypeIsConstCharPtrPtr(QualType T) {
+  if (!T->isPointerType())
+    return false;
+
+  return TypeIsConstCharPtr(T->getPointeeType());
+}
+
+bool lldb_rpc_gen::TypeIsDisallowedClass(QualType T) {
+  QualType UUT = GetUnqualifiedUnderlyingType(T);
+  const auto *CXXRDecl = UUT->getAsCXXRecordDecl();
+  if (!CXXRDecl)
+    return false;
+
+  llvm::StringRef DeclName = CXXRDecl->getName();
+  for (const llvm::StringRef DisallowedClass : DisallowedClasses)
+    if (DeclName == DisallowedClass)
+      return true;
+  return false;
+}
+
+bool lldb_rpc_gen::TypeIsCallbackFunctionPointer(QualType T) {
+  return T->isFunctionPointerType();
+}
+
+bool lldb_rpc_gen::MethodIsDisallowed(ASTContext &Context,
+                                      CXXMethodDecl *MDecl) {
+  bool isDisallowed = false;
+  std::string MangledName = lldb_rpc_gen::GetMangledName(Context, MDecl);
+  if (llvm::is_contained(DisallowedMethods, MangledName))
+    isDisallowed = true;
+
+  if (MDecl->hasAttrs()) {
+    for (auto *attr : MDecl->getAttrs()) {
+      if (strcmp(attr->getAttrName()->getNameStart(), "deprecated") == 0)
+        isDisallowed = true;
+    }
+  }
+  return isDisallowed;
+}
+
+bool lldb_rpc_gen::HasCallbackParameter(CXXMethodDecl *MDecl) {
+  bool HasCallbackParameter = false;
+  bool HasBatonParameter = false;
+  auto End = MDecl->parameters().end();
+  for (auto Iter = MDecl->parameters().begin(); Iter != End; Iter++) {
+    if ((*Iter)->getType()->isFunctionPointerType())
+      HasCallbackParameter = true;
+    else if ((*Iter)->getType()->isVoidPointerType())
+      HasBatonParameter = true;
+  }
+
+  return HasCallbackParameter && HasBatonParameter;
+}
+
+// Methods that have a pointer parameter followed by a length param need to be
+// kept track of in RPC. Such methods are annotated in the main SB API using
+// this Clang attribute: [[clang::annotate("lldb-rpc-gen pointer plus len")]].
+// This method checks that a given method has this attribute.
+//
+// NOTE: In the event that we end up using the Clang annotate attribute for
+// other things in RPC, we'd have to check the actual text for the annotation
+// and not just check if the method has an annotation at all.
----------------
chelcassanova wrote:

Good point, this annotation can also be placed behind a macro (similar to what 
we do with LLDB_DEPRECATED) such that we have:
"are we using lldb-rpc? if so, expand the macro to this attribute. otherwise, 
no-op"

And yes, it's better for futureproofing if we check the actual underlying text 
here.

https://github.com/llvm/llvm-project/pull/148981
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