[Sema] Make FunctionType's TSI use unadjusted argument types

This helps preserve the type-as-written in the AST, which we need for
MSVC mangling.  In particular, we need to preserve the types of array
parameters in function pointer types.

The essence of this change is:
-  QualType ArgTy = Param->getType();
+  QualType ArgTy = Param->getTypeSourceInfo()->getType();

... followed by the adjustment in ActOnFunctionDeclarator().

Differential Revision: http://llvm-reviews.chandlerc.com/D883

llvm-svn: 183614

4 files changed, 59 insertions, 39 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 44ff94e3584..384164167db 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -4142,6 +4142,21 @@ const ArrayType *ASTContext::getAsArrayType(QualType T) const {
 }
 
 QualType ASTContext::getAdjustedParameterType(QualType T) const {
+  // In ARC, infer a lifetime qualifier for appropriate parameter types.
+  if (getLangOpts().ObjCAutoRefCount &&
+      T.getObjCLifetime() == Qualifiers::OCL_None &&
+      T->isObjCLifetimeType()) {
+    // Special cases for arrays:
+    //   - if it's const, use __unsafe_unretained
+    //   - otherwise, it's an error
+    Qualifiers::ObjCLifetime lifetime;
+    if (T->isArrayType())
+      lifetime = Qualifiers::OCL_ExplicitNone;
+    else
+      lifetime = T->getObjCARCImplicitLifetime();
+    T = getLifetimeQualifiedType(T, lifetime);
+  }
+
   // C99 6.7.5.3p7:
   //   A declaration of a parameter as "array of type" shall be
   //   adjusted to "qualified pointer to type", where the type
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index c32df11b667..2c5233bce67 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -1781,8 +1781,10 @@ bool TypeOfExprType::isSugared() const {
 }
 
 QualType TypeOfExprType::desugar() const {
-  if (isSugared())
-    return getUnderlyingExpr()->getType();
+  if (isSugared()) {
+    Expr *E = getUnderlyingExpr();
+    return E->getType();
+  }
   
   return QualType(this, 0);
 }
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e6a89461b45..1db768b28a6 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5897,23 +5897,40 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
       << DeclSpec::getSpecifierName(TSCS);
 
   // Do not allow returning a objc interface by-value.
-  if (R->getAs<FunctionType>()->getResultType()->isObjCObjectType()) {
+  bool NeedsAdjustment = false;
+  const FunctionType *FT = R->castAs<FunctionType>();
+  QualType ResultTy = FT->getResultType();
+  if (ResultTy->isObjCObjectType()) {
     Diag(D.getIdentifierLoc(),
-         diag::err_object_cannot_be_passed_returned_by_value) << 0
-    << R->getAs<FunctionType>()->getResultType()
-    << FixItHint::CreateInsertion(D.getIdentifierLoc(), "*");
+         diag::err_object_cannot_be_passed_returned_by_value) << 0 << ResultTy
+        << FixItHint::CreateInsertion(D.getIdentifierLoc(), "*");
+    ResultTy = Context.getObjCObjectPointerType(ResultTy);
+    NeedsAdjustment = true;
+  }
 
-    QualType T = R->getAs<FunctionType>()->getResultType();
-    T = Context.getObjCObjectPointerType(T);
-    if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(R)) {
+  // Adjust parameter types from the type as written.
+  SmallVector<QualType, 16> AdjustedParms;
+  const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT);
+  if (FPT) {
+    for (FunctionProtoType::arg_type_iterator I = FPT->arg_type_begin(),
+         E = FPT->arg_type_end(); I != E; ++I) {
+      AdjustedParms.push_back(Context.getAdjustedParameterType(*I));
+      if (AdjustedParms.back() != *I)
+        NeedsAdjustment = true;
+    }
+  }
+
+  // Skip the type recreation if it isn't needed, for performance and to avoid
+  // prematurely desugaring things like typedefs and __typeofs.
+  if (NeedsAdjustment) {
+    if (FPT) {
       FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
-      R = Context.getFunctionType(T,
-                                  ArrayRef<QualType>(FPT->arg_type_begin(),
-                                                     FPT->getNumArgs()),
-                                  EPI);
+      R = Context.getFunctionType(ResultTy, AdjustedParms, EPI);
+    } else {
+      assert(isa<FunctionNoProtoType>(FT));
+      FunctionType::ExtInfo EI = FT->getExtInfo();
+      R = Context.getFunctionNoProtoType(ResultTy, EI);
     }
-    else if (isa<FunctionNoProtoType>(R))
-      R = Context.getFunctionNoProtoType(T);
   }
 
   bool isFriend = false;
@@ -8498,27 +8515,15 @@ ParmVarDecl *Sema::CheckParameter(DeclContext *DC, SourceLocation StartLoc,
                                   SourceLocation NameLoc, IdentifierInfo *Name,
                                   QualType T, TypeSourceInfo *TSInfo,
                                   VarDecl::StorageClass StorageClass) {
-  // In ARC, infer a lifetime qualifier for appropriate parameter types.
+  // Diagnose non-const parameter arrays of ARC types.
   if (getLangOpts().ObjCAutoRefCount &&
       T.getObjCLifetime() == Qualifiers::OCL_None &&
-      T->isObjCLifetimeType()) {
-
-    Qualifiers::ObjCLifetime lifetime;
-
-    // Special cases for arrays:
-    //   - if it's const, use __unsafe_unretained
-    //   - otherwise, it's an error
-    if (T->isArrayType()) {
-      if (!T.isConstQualified()) {
-        DelayedDiagnostics.add(
-            sema::DelayedDiagnostic::makeForbiddenType(
+      T->isObjCLifetimeType() &&
+      T->isArrayType() &&
+      !T.isConstQualified()) {
+    DelayedDiagnostics.add(
+        sema::DelayedDiagnostic::makeForbiddenType(
             NameLoc, diag::err_arc_array_param_no_ownership, T, false));
-      }
-      lifetime = Qualifiers::OCL_ExplicitNone;
-    } else {
-      lifetime = T->getObjCARCImplicitLifetime();
-    }
-    T = Context.getLifetimeQualifiedType(T, lifetime);
   }
 
   ParmVarDecl *New = ParmVarDecl::Create(Context, DC, StartLoc, NameLoc, Name,
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index e27d627d3ff..977294bd461 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1674,7 +1674,7 @@ QualType Sema::BuildFunctionType(QualType T,
   bool Invalid = false;
   for (unsigned Idx = 0, Cnt = ParamTypes.size(); Idx < Cnt; ++Idx) {
     // FIXME: Loc is too inprecise here, should use proper locations for args.
-    QualType ParamType = Context.getAdjustedParameterType(ParamTypes[Idx]);
+    QualType ParamType = ParamTypes[Idx];
     if (ParamType->isVoidType()) {
       Diag(Loc, diag::err_param_with_void_type);
       Invalid = true;
@@ -2798,13 +2798,11 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
 
         for (unsigned i = 0, e = FTI.NumArgs; i != e; ++i) {
           ParmVarDecl *Param = cast<ParmVarDecl>(FTI.ArgInfo[i].Param);
-          QualType ArgTy = Param->getType();
+          // Get the type as written.  It will be adjusted later in
+          // ActOnFunctionDeclarator().
+          QualType ArgTy = Param->getTypeSourceInfo()->getType();
           assert(!ArgTy.isNull() && "Couldn't parse type?");
 
-          // Adjust the parameter type.
-          assert((ArgTy == Context.getAdjustedParameterType(ArgTy)) &&
-                 "Unadjusted type?");
-
           // Look for 'void'.  void is allowed only as a single argument to a
           // function with no other parameters (C99 6.7.5.3p10).  We record
           // int(void) as a FunctionProtoType with an empty argument list.