[CodeView] Initial support for emitting S_THUNK32 symbols for compiler...

When emitting CodeView debug information, compiler-generated thunk routines
should be emitted using S_THUNK32 symbols instead of S_GPROC32_ID symbols so
Visual Studio can properly step into the user code.  This initial support only
handles standard thunk ordinals.

Differential Revision: https://reviews.llvm.org/D43838

llvm-svn: 330132

4 files changed, 285 insertions, 30 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 47b8e436752..bdd326d70e4 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3217,7 +3217,8 @@ llvm::DISubroutineType *CGDebugInfo::getOrCreateFunctionType(const Decl *D,
 
 void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
                                     SourceLocation ScopeLoc, QualType FnType,
-                                    llvm::Function *Fn, CGBuilderTy &Builder) {
+                                    llvm::Function *Fn, bool CurFuncIsThunk,
+                                    CGBuilderTy &Builder) {
 
   StringRef Name;
   StringRef LinkageName;
@@ -3263,6 +3264,10 @@ void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
     // Artificial functions should not silently reuse CurLoc.
     CurLoc = SourceLocation();
   }
+
+  if (CurFuncIsThunk)
+    Flags |= llvm::DINode::FlagThunk;
+
   unsigned LineNo = getLineNumber(Loc);
   unsigned ScopeLine = getLineNumber(ScopeLoc);
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 459d7e00b6f..5cd77177972 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -366,7 +366,8 @@ public:
   /// \param ScopeLoc  The location of the function body.
   void EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
                          SourceLocation ScopeLoc, QualType FnType,
-                         llvm::Function *Fn, CGBuilderTy &Builder);
+                         llvm::Function *Fn, bool CurFnIsThunk,
+                         CGBuilderTy &Builder);
 
   /// Start a new scope for an inlined function.
   void EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD);
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 357f0d74376..92564043e07 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1018,7 +1018,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
       ArgTypes.push_back(VD->getType());
     QualType FnType = getContext().getFunctionType(
         RetTy, ArgTypes, FunctionProtoType::ExtProtoInfo(CC));
-    DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder);
+    DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, CurFuncIsThunk,
+                          Builder);
   }
 
   if (ShouldInstrumentFunction()) {
diff --git a/clang/test/CodeGenCXX/debug-info-thunk.cpp b/clang/test/CodeGenCXX/debug-info-thunk.cpp
index f7d16f49325..56dec93f6b3 100644
--- a/clang/test/CodeGenCXX/debug-info-thunk.cpp
+++ b/clang/test/CodeGenCXX/debug-info-thunk.cpp
@@ -1,29 +1,277 @@
-// RUN: %clang_cc1 %s -triple %itanium_abi_triple -debug-info-kind=limited -S -emit-llvm -o - | FileCheck %s
-
-struct A {
-  virtual void f();
-};
-
-struct B {
-  virtual void f();
-};
-
-struct C : A, B {
-  virtual void f();
-};
-
-void C::f() { }
-// CHECK: define {{.*}}void @_ZThn{{[48]}}_N1C1fEv
-// CHECK-SAME: !dbg ![[SP:[0-9]+]]
-// CHECK-NOT: {{ret }}
-// CHECK: = load{{.*}} !dbg ![[DBG:[0-9]+]]
-// CHECK-NOT: {{ret }}
-// CHECK: ret void, !dbg ![[DBG]]
+// RUN: %clang_cc1 %s -triple=x86_64-pc-windows-msvc -debug-info-kind=limited -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple %itanium_abi_triple -debug-info-kind=limited -S -emit-llvm -o - | FileCheck %s -check-prefix=ITANIUM
 //
-// CHECK: ![[SP]] = distinct !DISubprogram(linkageName: "_ZThn{{[48]}}_N1C1fEv"
-// CHECK-SAME:          line: 15
-// CHECK-SAME:          isDefinition: true
-// CHECK-SAME:          DIFlagArtificial
-// CHECK-SAME:          ){{$}}
+// Validate we emit a "DIFlagThunk" flag on DISubprogram entries for thunks.
+// This flag is used for emitting S_THUNK32 symbols for CodeView debugging.
 //
-// CHECK: ![[DBG]] = !DILocation(line: 0
+// NOTE:
+// Because thunks are compiler generated and don't exist in the source, this
+// test is dependent upon the linkage name to identify the thunk.  Any changes
+// in the name mangling may require this test to be updated.
+//
+// NOTE:
+// The FileCheck directives below use CHECK-DAG because the thunks may not be
+// emitted in source order.
+//
+
+namespace Test1 {
+  struct A {
+    virtual void f();
+  };
+  
+  struct B {
+    virtual void f();
+  };
+  
+  struct C : A, B {
+    virtual void c();
+    
+    virtual void f();
+  };
+  
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@Test1@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+  void C::f() { }
+}
+
+namespace Test2 {
+  struct V1 { };
+  struct V2 : virtual V1 { };
+  
+  struct A {
+    virtual V1 *f();
+  };
+  
+  struct B : A {
+    virtual void b();
+    
+    virtual V2 *f();
+  };
+  
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@B@Test2@@QEAAPEAUV1@2@XZ"{{.*}} flags: {{.*}}DIFlagThunk
+  V2 *B::f() { return 0; }
+}
+
+namespace Test3 {
+  struct A {
+    virtual void f();
+  };
+  
+  struct B {
+    virtual void f();
+  };
+  
+  struct __attribute__((visibility("protected"))) C : A, B {
+    virtual void c();
+    
+    virtual void f();
+  };
+  
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@Test3@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+  void C::f() { }
+}
+
+namespace Test4 {
+  struct A {
+    virtual void f();
+  };
+
+  struct B {
+    virtual void f();
+  };
+
+  namespace {
+    struct C : A, B {
+      virtual void c();
+      virtual void f();
+    };
+  }
+  void C::c() {}
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@?A@Test4@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+  void C::f() {}
+
+  // Force C::f to be used.
+  void f() { 
+    C c; 
+    c.f();
+  }
+}
+
+namespace Test5 {
+  struct X {
+    X();
+    X(const X&);
+    X &operator=(const X&);
+    ~X();
+  };
+
+  struct P {
+    P();
+    P(const P&);
+    ~P();
+    X first;
+    X second;
+  };
+
+  P getP();
+
+  struct Base1 {
+    int i;
+
+    virtual X f() { return X(); }
+  };
+
+  struct Base2 {
+    float real;
+
+    virtual X f() { return X(); }
+  };
+
+  struct Thunks : Base1, Base2 {
+    long l;
+
+    virtual X f();
+  };
+
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@Thunks@Test5@@WBA@EAA?AUX@2@XZ"{{.*}} flags: {{.*}}DIFlagThunk
+  X Thunks::f() { return X(); }
+}
+
+namespace Test6 {
+  struct X {
+    X();
+    X(const X&);
+    X &operator=(const X&);
+    ~X();
+  };
+
+  struct Small { short s; };
+  struct Large {
+    char array[1024];
+  };
+
+  class A {
+  protected:
+    virtual void foo() = 0;
+  };
+
+  class B : public A {
+  protected:
+    virtual void bar() = 0;
+  };
+
+  class C : public A  {
+  protected:
+    virtual void baz(X, X&, _Complex float, Small, Small&, Large) = 0;
+  };
+
+  class D : public B,
+            public C {
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?foo@D@Test6@@G7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+    void foo() {}
+    void bar() {}
+    void baz(X, X&, _Complex float, Small, Small&, Large);
+  };
+
+  void D::baz(X, X&, _Complex float, Small, Small&, Large) { }
+
+  void testD() { D d; }
+}
+
+namespace Test7 {
+  struct A { virtual void foo(); };
+  struct B { virtual void foo(); };
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?foo@C@Test7@@W7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+  struct C : A, B { void foo() {} };
+
+  // Test later.
+  void test() {
+    C c;
+  }
+}
+
+namespace Test8 {
+  struct A {             virtual A* f(); };
+  struct B : virtual A { virtual A* f(); };
+  struct C : B         { virtual C* f(); };
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@Test8@@QEAAPEAUA@2@XZ"{{.*}} flags: {{.*}}DIFlagThunk
+  C* C::f() { return 0; }
+}
+
+namespace Test9 {
+  struct B1 {
+    virtual B1 &foo1();
+  };
+  struct Pad1 {
+    virtual ~Pad1();
+  };
+  struct Proxy1 : Pad1, B1 {
+    virtual ~Proxy1();
+  };
+  struct D : virtual Proxy1 {
+    virtual ~D();
+    virtual D &foo1();
+  };
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?foo1@D@Test9@@$4PPPPPPPE@A@EAAAEAUB1@2@XZ"{{.*}} flags: {{.*}}DIFlagThunk
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?foo1@D@Test9@@$4PPPPPPPE@A@EAAAEAU12@XZ"{{.*}} flags: {{.*}}DIFlagThunk
+  D& D::foo1() {
+    return *this;
+  }
+}
+
+namespace Test10 {
+  class A {
+    virtual void f();
+  };
+  class B {
+    virtual void f();
+  };
+  class C : public A, public B  {
+    virtual void f();
+  };
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "?f@C@Test10@@G7EAAXXZ"{{.*}} flags: {{.*}}DIFlagThunk
+  void C::f() {
+  }
+}
+
+namespace Test11 {
+  class A {
+  public:
+    virtual void f();
+  };
+
+  void test() {
+// CHECK-DAG: DISubprogram{{.*}}linkageName: "??_9A@Test11@@$BA@AA"{{.*}} flags: {{.*}}DIFlagThunk
+    void (A::*p)() = &A::f;
+  }
+}
+
+namespace Test12 {
+  struct A {
+    virtual void f();
+  };
+  
+  struct B {
+    virtual void f();
+  };
+  
+  struct C : A, B {
+    virtual void f();
+  };
+  
+  void C::f() { }
+  // ITANIUM: define {{.*}}void @_ZThn{{[48]}}_N6Test121C1fEv
+  // ITANIUM-SAME: !dbg ![[SP:[0-9]+]]
+  // ITANIUM-NOT: {{ret }}
+  // ITANIUM: = load{{.*}} !dbg ![[DBG:[0-9]+]]
+  // ITANIUM-NOT: {{ret }}
+  // ITANIUM: ret void, !dbg ![[DBG]]
+  //
+  // ITANIUM: ![[SP]] = distinct !DISubprogram(linkageName: "_ZThn{{[48]}}_N6Test121C1fEv"
+  // ITANIUM-SAME:          line: 261
+  // ITANIUM-SAME:          isDefinition: true
+  // ITANIUM-SAME:          DIFlagArtificial
+  // ITANIUM-SAME:          DIFlagThunk
+  // ITANIUM-SAME:          ){{$}}
+  //
+  // ITANIUM: ![[DBG]] = !DILocation(line: 0
+}