[MS] Fix for bug 25013 - #pragma vtordisp is unknown inside functions, by Denis Zobnin.

This patch adds support of #pragma vtordisp inside functions in attempt to improve compatibility. Microsoft compiler appears to save the stack of vtordisp modes on entry of struct methods' bodies and restore it on exit (method-local vtordisp).
Differential Revision: http://reviews.llvm.org/D14467



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@253650 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Sema/Sema.h

@@ -1007,6 +1007,24 @@ public:
     bool OldFPContractState : 1;
   };
 
+  /// Records and restores the vtordisp state on entry/exit of C++ method body.
+  class VtorDispStackRAII {
+  public:
+    VtorDispStackRAII(Sema &S, bool ShouldSaveAndRestore)
+      : S(S), ShouldSaveAndRestore(ShouldSaveAndRestore), OldVtorDispStack() {
+      if (ShouldSaveAndRestore)
+        OldVtorDispStack = S.VtorDispModeStack;
+    }
+    ~VtorDispStackRAII() {
+      if (ShouldSaveAndRestore)
+        S.VtorDispModeStack = OldVtorDispStack;
+    }
+  private:
+    Sema &S;
+    bool ShouldSaveAndRestore;
+    SmallVector<MSVtorDispAttr::Mode, 2> OldVtorDispStack;
+  };
+
   void addImplicitTypedef(StringRef Name, QualType T);
 
 public:

lib/Parse/ParseDeclCXX.cpp

@@ -2854,6 +2854,11 @@ Parser::DeclGroupPtrTy Parser::ParseCXXClassMemberDeclarationWithPragmas(
     return DeclGroupPtrTy();
   }
 
+  if (Tok.is(tok::annot_pragma_ms_vtordisp)) {
+    HandlePragmaMSVtorDisp();
+    return DeclGroupPtrTy();
+  }
+
   // If we see a namespace here, a close brace was missing somewhere.
   if (Tok.is(tok::kw_namespace)) {
     DiagnoseUnexpectedNamespace(cast<NamedDecl>(TagDecl));

lib/Parse/ParseStmt.cpp

@@ -358,6 +358,11 @@ Retry:
     HandlePragmaMSPragma();
     return StmtEmpty();
 
+  case tok::annot_pragma_ms_vtordisp:
+    ProhibitAttributes(Attrs);
+    HandlePragmaMSVtorDisp();
+    return StmtEmpty();
+
   case tok::annot_pragma_loop_hint:
     ProhibitAttributes(Attrs);
     return ParsePragmaLoopHint(Stmts, OnlyStatement, TrailingElseLoc, Attrs);
@@ -885,6 +890,9 @@ void Parser::ParseCompoundStatementLeadingPragmas() {
     case tok::annot_pragma_ms_pragma:
       HandlePragmaMSPragma();
       break;
+    case tok::annot_pragma_ms_vtordisp:
+      HandlePragmaMSVtorDisp();
+      break;
     default:
       checkForPragmas = false;
       break;
@@ -1895,6 +1903,11 @@ Decl *Parser::ParseFunctionStatementBody(Decl *Decl, ParseScope &BodyScope) {
   PrettyDeclStackTraceEntry CrashInfo(Actions, Decl, LBraceLoc,
                                       "parsing function body");
 
+  // Save and reset current vtordisp stack if we have entered a C++ method body.
+  bool IsCXXMethod =
+      getLangOpts().CPlusPlus && Decl && isa<CXXMethodDecl>(Decl);
+  Sema::VtorDispStackRAII SavedVtorDispStack(Actions, IsCXXMethod);
+
   // Do not enter a scope for the brace, as the arguments are in the same scope
   // (the function body) as the body itself.  Instead, just read the statement
   // list and put it into a CompoundStmt for safe keeping.
@@ -1934,6 +1947,11 @@ Decl *Parser::ParseFunctionTryBlock(Decl *Decl, ParseScope &BodyScope) {
     return Actions.ActOnSkippedFunctionBody(Decl);
   }
 
+  // Save and reset current vtordisp stack if we have entered a C++ method body.
+  bool IsCXXMethod =
+      getLangOpts().CPlusPlus && Decl && isa<CXXMethodDecl>(Decl);
+  Sema::VtorDispStackRAII SavedVtorDispStack(Actions, IsCXXMethod);
+
   SourceLocation LBraceLoc = Tok.getLocation();
   StmtResult FnBody(ParseCXXTryBlockCommon(TryLoc, /*FnTry*/true));
   // If we failed to parse the try-catch, we just give the function an empty

test/Layout/ms-vtordisp-local.cpp

@@ -0,0 +1,217 @@
+// RUN: %clang_cc1 -fms-extensions -fexceptions -fcxx-exceptions -emit-llvm-only -triple x86_64-pc-win32 -fdump-record-layouts -fsyntax-only %s 2>&1 | FileCheck %s
+
+struct Base {
+  virtual ~Base() {}
+  virtual void BaseFunc() {}
+};
+
+#pragma vtordisp(0)
+
+struct Container {
+  static void f() try {
+    #pragma vtordisp(2)
+    struct HasVtorDisp : virtual Base {
+      virtual ~HasVtorDisp() {}
+      virtual void Func() {}
+    };
+
+    int x[sizeof(HasVtorDisp)];
+
+    // HasVtorDisp: vtordisp because of pragma right before it.
+    //
+    // CHECK: *** Dumping AST Record Layout
+    // CHECK: *** Dumping AST Record Layout
+    // CHECK-NEXT:          0 | struct HasVtorDisp
+    // CHECK-NEXT:          0 |   (HasVtorDisp vftable pointer)
+    // CHECK-NEXT:          8 |   (HasVtorDisp vbtable pointer)
+    // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+    // CHECK-NEXT:         24 |   struct Base (virtual base)
+    // CHECK-NEXT:         24 |     (Base vftable pointer)
+    // CHECK-NEXT:            | [sizeof=32, align=8,
+    // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+  } catch (...) {
+  }
+};
+
+struct NoVtorDisp1 : virtual Base {
+  virtual ~NoVtorDisp1() {}
+  virtual void Func() {}
+};
+
+int x1[sizeof(NoVtorDisp1)];
+
+// NoVtroDisp1: no vtordisp because of pragma disabling it.
+//
+// CHECK: *** Dumping AST Record Layout
+// CHECK-NEXT:          0 | struct NoVtorDisp1
+// CHECK-NEXT:          0 |   (NoVtorDisp1 vftable pointer)
+// CHECK-NEXT:          8 |   (NoVtorDisp1 vbtable pointer)
+// CHECK-NEXT:         16 |   struct Base (virtual base)
+// CHECK-NEXT:         16 |     (Base vftable pointer)
+// CHECK-NEXT:            | [sizeof=24, align=8,
+// CHECK-NEXT:            |  nvsize=16, nvalign=8]
+
+struct Container2 {
+  static void f1() {
+    // Local pragma #1 - must be disabled on exit from f1().
+    #pragma vtordisp(push, 2)
+    struct HasVtorDisp1 : virtual Base {
+      virtual ~HasVtorDisp1() {}
+      virtual void Func() {}
+    };
+
+    int x2[sizeof(HasVtorDisp1)];
+
+    // HasVtorDisp1: vtordisp because of pragma right before it.
+    //
+    // CHECK: *** Dumping AST Record Layout
+    // CHECK-NEXT:          0 | struct HasVtorDisp1
+    // CHECK-NEXT:          0 |   (HasVtorDisp1 vftable pointer)
+    // CHECK-NEXT:          8 |   (HasVtorDisp1 vbtable pointer)
+    // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+    // CHECK-NEXT:         24 |   struct Base (virtual base)
+    // CHECK-NEXT:         24 |     (Base vftable pointer)
+    // CHECK-NEXT:            | [sizeof=32, align=8,
+    // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+
+    struct InnerContainer {
+      static void g1() {
+        struct HasVtorDisp2 : virtual Base {
+          virtual ~HasVtorDisp2() {}
+          virtual void Func() {}
+        };
+
+        int x3[sizeof(HasVtorDisp2)];
+
+        // HasVtorDisp2: vtordisp because of vtordisp(2) in f1().
+        //
+        // CHECK: *** Dumping AST Record Layout
+        // CHECK-NEXT:          0 | struct HasVtorDisp2
+        // CHECK-NEXT:          0 |   (HasVtorDisp2 vftable pointer)
+        // CHECK-NEXT:          8 |   (HasVtorDisp2 vbtable pointer)
+        // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+        // CHECK-NEXT:         24 |   struct Base (virtual base)
+        // CHECK-NEXT:         24 |     (Base vftable pointer)
+        // CHECK-NEXT:            | [sizeof=32, align=8,
+        // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+
+        // Local pragma #2 - must be disabled on exit from g1().
+        #pragma vtordisp(push, 0)
+        struct NoVtorDisp2 : virtual Base {
+          virtual ~NoVtorDisp2() {}
+          virtual void Func() {}
+        };
+
+        int x4[sizeof(NoVtorDisp2)];
+
+        // NoVtroDisp2: no vtordisp because of vtordisp(0) in g1().
+        //
+        // CHECK: *** Dumping AST Record Layout
+        // CHECK-NEXT:          0 | struct NoVtorDisp2
+        // CHECK-NEXT:          0 |   (NoVtorDisp2 vftable pointer)
+        // CHECK-NEXT:          8 |   (NoVtorDisp2 vbtable pointer)
+        // CHECK-NEXT:         16 |   struct Base (virtual base)
+        // CHECK-NEXT:         16 |     (Base vftable pointer)
+        // CHECK-NEXT:            | [sizeof=24, align=8,
+        // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+      }
+
+      static void g2() {
+        struct HasVtorDisp3 : virtual Base {
+          virtual ~HasVtorDisp3() {}
+          virtual void Func() {}
+        };
+
+        int x5[sizeof(HasVtorDisp3)];
+
+        // HasVtorDisp3: vtordisp because of vtordisp(2) in f1(),
+        //               local vtordisp(0) in g1() is disabled.
+        //
+        // CHECK: *** Dumping AST Record Layout
+        // CHECK-NEXT:          0 | struct HasVtorDisp3
+        // CHECK-NEXT:          0 |   (HasVtorDisp3 vftable pointer)
+        // CHECK-NEXT:          8 |   (HasVtorDisp3 vbtable pointer)
+        // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+        // CHECK-NEXT:         24 |   struct Base (virtual base)
+        // CHECK-NEXT:         24 |     (Base vftable pointer)
+        // CHECK-NEXT:            | [sizeof=32, align=8,
+        // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+      }
+    };
+
+    struct HasVtorDisp4 : virtual Base {
+      virtual ~HasVtorDisp4() {}
+      virtual void Func() {}
+    };
+
+    int x6[sizeof(HasVtorDisp4)];
+
+    // HasVtorDisp4: vtordisp because of vtordisp(2) in f1(),
+    //               local vtordisp(0) in g1() is disabled,
+    //               g2() has no pragmas - stack is not affected.
+    //
+    // CHECK: *** Dumping AST Record Layout
+    // CHECK-NEXT:          0 | struct HasVtorDisp4
+    // CHECK-NEXT:          0 |   (HasVtorDisp4 vftable pointer)
+    // CHECK-NEXT:          8 |   (HasVtorDisp4 vbtable pointer)
+    // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+    // CHECK-NEXT:         24 |   struct Base (virtual base)
+    // CHECK-NEXT:         24 |     (Base vftable pointer)
+    // CHECK-NEXT:            | [sizeof=32, align=8,
+    // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+
+    InnerContainer::g1();
+    InnerContainer::g2();
+  }
+
+  static void f2() {
+    struct NoVtorDisp3 : virtual Base {
+      virtual ~NoVtorDisp3() {}
+      virtual void Func() {}
+    };
+
+    int x7[sizeof(NoVtorDisp3)];
+
+    // NoVtroDisp3: no vtordisp because of global pragma (0),
+    //              local vtordisp(2) is disabled on exit from f1().
+    //
+    // CHECK: *** Dumping AST Record Layout
+    // CHECK-NEXT:          0 | struct NoVtorDisp3
+    // CHECK-NEXT:          0 |   (NoVtorDisp3 vftable pointer)
+    // CHECK-NEXT:          8 |   (NoVtorDisp3 vbtable pointer)
+    // CHECK-NEXT:         16 |   struct Base (virtual base)
+    // CHECK-NEXT:         16 |     (Base vftable pointer)
+    // CHECK-NEXT:            | [sizeof=24, align=8,
+    // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+  }
+};
+
+struct Container3 {
+  #pragma vtordisp(2)
+  struct HasVtorDisp5 : virtual Base {
+    virtual ~HasVtorDisp5() {}
+    virtual void Func() {}
+  };
+
+  int x8[sizeof(HasVtorDisp5)];
+
+  // HasVtorDisp5: vtordisp because of pragma right before it.
+  //
+  // CHECK: *** Dumping AST Record Layout
+  // CHECK-NEXT:          0 | struct Container3::HasVtorDisp5
+  // CHECK-NEXT:          0 |   (HasVtorDisp5 vftable pointer)
+  // CHECK-NEXT:          8 |   (HasVtorDisp5 vbtable pointer)
+  // CHECK-NEXT:         20 |   (vtordisp for vbase Base)
+  // CHECK-NEXT:         24 |   struct Base (virtual base)
+  // CHECK-NEXT:         24 |     (Base vftable pointer)
+  // CHECK-NEXT:            | [sizeof=32, align=8,
+  // CHECK-NEXT:            |  nvsize=16, nvalign=8]
+};
+
+int main() {
+  Container::f();
+  Container2::f1();
+  Container2::f2();
+  Container3 cont3;
+  return 0;
+};

test/SemaCXX/pragma-vtordisp.cpp

@@ -32,9 +32,41 @@ struct B : virtual A { int b; };
 #pragma vtordisp(), stuff // expected-warning {{extra tokens}}
 
 struct C {
-// FIXME: Our implementation based on token insertion makes it impossible for
-// the pragma to appear everywhere we should support it.
-//#pragma vtordisp()
+#pragma vtordisp()
   struct D : virtual A {
   };
 };
+
+struct E {
+  virtual ~E();
+  virtual void f();
+};
+
+#pragma vtordisp(pop) // expected-warning {{#pragma vtordisp(pop, ...) failed: stack empty}}
+
+void g() {
+  #pragma vtordisp(push, 2)
+  struct F : virtual E {
+    virtual ~F();
+    virtual void f();
+  };
+}
+
+#pragma vtordisp(pop) // OK because of local vtordisp(2) in g().
+
+struct G {
+  void f() {
+    #pragma vtordisp(push, 2) // Method-local pragma - stack will be restored on exit.
+  }
+};
+
+// Stack is restored on exit from G::f(), nothing to pop.
+#pragma vtordisp(pop) // expected-warning {{#pragma vtordisp(pop, ...) failed: stack empty}}
+
+int g2()
+// FIXME: Our implementation based on token insertion makes it impossible for
+// the pragma to appear everywhere we should support it.
+// #pragma vtordisp()
+{
+  return 0;
+}