[PDB] Restore the calling convention from PDB

Summary:
This patch implements restoring of the calling convention from PDB.
It is necessary for expressions evaluation, if we want to call a function
of the debuggee process with a calling convention other than ccall.

Reviewers: clayborg, zturner, labath, asmith

Reviewed By: clayborg

Subscribers: teemperor, lldb-commits, stella.stamenova

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D52501

6 files changed, 77 insertions, 4 deletions

diff --git a/lldb/include/lldb/Symbol/ClangASTContext.h b/lldb/include/lldb/Symbol/ClangASTContext.h
index abb64689286..1e13ba93f85 100644
--- a/lldb/include/lldb/Symbol/ClangASTContext.h
+++ b/lldb/include/lldb/Symbol/ClangASTContext.h
@@ -377,7 +377,17 @@ public:
                                          const CompilerType &result_type,
                                          const CompilerType *args,
                                          unsigned num_args, bool is_variadic,
-                                         unsigned type_quals);
+                                         unsigned type_quals,
+                                         clang::CallingConv cc);
+
+  static CompilerType CreateFunctionType(clang::ASTContext *ast,
+                                         const CompilerType &result_type,
+                                         const CompilerType *args,
+                                         unsigned num_args, bool is_variadic,
+                                         unsigned type_quals) {
+    return ClangASTContext::CreateFunctionType(
+        ast, result_type, args, num_args, is_variadic, type_quals, clang::CC_C);
+  }
 
   CompilerType CreateFunctionType(const CompilerType &result_type,
                                   const CompilerType *args, unsigned num_args,
@@ -386,6 +396,15 @@ public:
         getASTContext(), result_type, args, num_args, is_variadic, type_quals);
   }
 
+  CompilerType CreateFunctionType(const CompilerType &result_type,
+                                  const CompilerType *args, unsigned num_args,
+                                  bool is_variadic, unsigned type_quals,
+                                  clang::CallingConv cc) {
+    return ClangASTContext::CreateFunctionType(getASTContext(), result_type,
+                                               args, num_args, is_variadic,
+                                               type_quals, cc);
+  }
+
   clang::ParmVarDecl *CreateParameterDeclaration(const char *name,
                                                  const CompilerType &param_type,
                                                  int storage);
diff --git a/lldb/lit/SymbolFile/PDB/Inputs/CallingConventionsTest.cpp b/lldb/lit/SymbolFile/PDB/Inputs/CallingConventionsTest.cpp
new file mode 100644
index 00000000000..60854c04c60
--- /dev/null
+++ b/lldb/lit/SymbolFile/PDB/Inputs/CallingConventionsTest.cpp
@@ -0,0 +1,20 @@
+int FuncCCall() { return 0; }
+auto FuncCCallPtr = &FuncCCall;
+
+int __stdcall FuncStdCall() { return 0; }
+auto FuncStdCallPtr = &FuncStdCall;
+
+int __fastcall FuncFastCall() { return 0; }
+auto FuncFastCallPtr = &FuncFastCall;
+
+int __vectorcall FuncVectorCall() { return 0; }
+auto FuncVectorCallPtr = &FuncVectorCall;
+
+struct S {
+  int FuncThisCall() { return 0; }
+};
+auto FuncThisCallPtr = &S::FuncThisCall;
+
+int main() {
+  return 0;
+}
diff --git a/lldb/lit/SymbolFile/PDB/calling-conventions.test b/lldb/lit/SymbolFile/PDB/calling-conventions.test
new file mode 100644
index 00000000000..cc1474945e1
--- /dev/null
+++ b/lldb/lit/SymbolFile/PDB/calling-conventions.test
@@ -0,0 +1,11 @@
+REQUIRES: windows, lld
+RUN: clang-cl -m32 /Zi /GS- /c %S/Inputs/CallingConventionsTest.cpp /o %t.obj
+RUN: lld-link /debug:full /nodefaultlib /entry:main %t.obj /out:%t.exe
+RUN: lldb-test symbols -dump-ast %t.exe | FileCheck %s
+
+CHECK: Module: {{.*}}
+CHECK-DAG: int (*FuncCCallPtr)();
+CHECK-DAG: int (*FuncStdCallPtr)() __attribute__((stdcall));
+CHECK-DAG: int (*FuncFastCallPtr)() __attribute__((fastcall));
+CHECK-DAG: int (*FuncVectorCallPtr)() __attribute__((vectorcall));
+CHECK-DAG: int (S::*FuncThisCallPtr)() __attribute__((thiscall));
diff --git a/lldb/lit/SymbolFile/PDB/pointers.test b/lldb/lit/SymbolFile/PDB/pointers.test
index 3924989ab58..03e31c4ff3c 100644
--- a/lldb/lit/SymbolFile/PDB/pointers.test
+++ b/lldb/lit/SymbolFile/PDB/pointers.test
@@ -28,7 +28,7 @@ MAIN-SAME:    (int *), scope = local
 MAIN:     Variable{{.*}}, name = "p_member_field"
 MAIN-SAME:    (int ST::*), scope = local
 MAIN:     Variable{{.*}}, name = "p_member_method"
-MAIN-SAME:    (int (ST::*)(int)), scope = local
+MAIN-SAME:    (int (ST::*)(int) __attribute__((thiscall))), scope = local
 
 F:   Function{[[FID2:.*]]}, demangled = {{.*}}f(int)
 F-NEXT:  Block{[[FID2]]}
diff --git a/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp b/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
index a4c4459bf56..50076307001 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
+++ b/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
@@ -331,6 +331,26 @@ static bool IsAnonymousNamespaceName(const std::string &name) {
   return name == "`anonymous namespace'" || name == "`anonymous-namespace'";
 }
 
+static clang::CallingConv TranslateCallingConvention(PDB_CallingConv pdb_cc) {
+  switch (pdb_cc) {
+  case llvm::codeview::CallingConvention::NearC:
+    return clang::CC_C;
+  case llvm::codeview::CallingConvention::NearStdCall:
+    return clang::CC_X86StdCall;
+  case llvm::codeview::CallingConvention::NearFast:
+    return clang::CC_X86FastCall;
+  case llvm::codeview::CallingConvention::ThisCall:
+    return clang::CC_X86ThisCall;
+  case llvm::codeview::CallingConvention::NearVector:
+    return clang::CC_X86VectorCall;
+  case llvm::codeview::CallingConvention::NearPascal:
+    return clang::CC_X86Pascal;
+  default:
+    assert(false && "Unknown calling convention");
+    return clang::CC_C;
+  }
+}
+
 PDBASTParser::PDBASTParser(lldb_private::ClangASTContext &ast) : m_ast(ast) {}
 
 PDBASTParser::~PDBASTParser() {}
@@ -603,9 +623,10 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
       type_quals |= clang::Qualifiers::Const;
     if (func_sig->isVolatileType())
       type_quals |= clang::Qualifiers::Volatile;
+    auto cc = TranslateCallingConvention(func_sig->getCallingConvention());
     CompilerType func_sig_ast_type =
         m_ast.CreateFunctionType(return_ast_type, arg_list.data(),
-                                 arg_list.size(), is_variadic, type_quals);
+                                 arg_list.size(), is_variadic, type_quals, cc);
 
     GetDeclarationForSymbol(type, decl);
     return std::make_shared<lldb_private::Type>(
diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
index 23e94884e37..fe47f29f18b 100644
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -2058,7 +2058,8 @@ FunctionDecl *ClangASTContext::CreateFunctionDeclaration(
 
 CompilerType ClangASTContext::CreateFunctionType(
     ASTContext *ast, const CompilerType &result_type, const CompilerType *args,
-    unsigned num_args, bool is_variadic, unsigned type_quals) {
+    unsigned num_args, bool is_variadic, unsigned type_quals,
+    clang::CallingConv cc) {
   if (ast == nullptr)
     return CompilerType(); // invalid AST
 
@@ -2086,6 +2087,7 @@ CompilerType ClangASTContext::CreateFunctionType(
 
   // TODO: Detect calling convention in DWARF?
   FunctionProtoType::ExtProtoInfo proto_info;
+  proto_info.ExtInfo = cc;
   proto_info.Variadic = is_variadic;
   proto_info.ExceptionSpec = EST_None;
   proto_info.TypeQuals = type_quals;