Template instantiation for "if" statements. Also:

  - Skip semantic analysis of the "if" condition if it is type-dependent.
  - Added the location of the "else" keyword into IfStmt, so that we can
    provide it for type-checking after template instantiation.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71875 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 61 insertions, 13 deletions

diff --git a/include/clang/AST/Stmt.h b/include/clang/AST/Stmt.h
index 99e49722af..14afcfcd62 100644
--- a/include/clang/AST/Stmt.h
+++ b/include/clang/AST/Stmt.h
@@ -540,13 +540,16 @@ class IfStmt : public Stmt {
   enum { COND, THEN, ELSE, END_EXPR };
   Stmt* SubExprs[END_EXPR];
   SourceLocation IfLoc;
+  SourceLocation ElseLoc;
 public:
-  IfStmt(SourceLocation IL, Expr *cond, Stmt *then, Stmt *elsev = 0) 
+  IfStmt(SourceLocation IL, Expr *cond, Stmt *then, 
+         SourceLocation EL = SourceLocation(), Stmt *elsev = 0) 
     : Stmt(IfStmtClass)  {
     SubExprs[COND] = reinterpret_cast<Stmt*>(cond);
     SubExprs[THEN] = then;
     SubExprs[ELSE] = elsev;
     IfLoc = IL;
+    ElseLoc = EL;
   }
   
   /// \brief Build an empty if/then/else statement
@@ -565,6 +568,8 @@ public:
 
   SourceLocation getIfLoc() const { return IfLoc; }
   void setIfLoc(SourceLocation L) { IfLoc = L; }
+  SourceLocation getElseLoc() const { return ElseLoc; }
+  void setElseLoc(SourceLocation L) { ElseLoc = L; }
 
   virtual SourceRange getSourceRange() const { 
     if (SubExprs[ELSE])
diff --git a/lib/Frontend/PCHReaderStmt.cpp b/lib/Frontend/PCHReaderStmt.cpp
index 1c6f3f1da7..eb8dab968b 100644
--- a/lib/Frontend/PCHReaderStmt.cpp
+++ b/lib/Frontend/PCHReaderStmt.cpp
@@ -172,6 +172,7 @@ unsigned PCHStmtReader::VisitIfStmt(IfStmt *S) {
   S->setThen(StmtStack[StmtStack.size() - 2]);
   S->setElse(StmtStack[StmtStack.size() - 1]);
   S->setIfLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
+  S->setElseLoc(SourceLocation::getFromRawEncoding(Record[Idx++]));
   return 3;
 }
 
diff --git a/lib/Frontend/PCHWriterStmt.cpp b/lib/Frontend/PCHWriterStmt.cpp
index d37df07d07..af5d563587 100644
--- a/lib/Frontend/PCHWriterStmt.cpp
+++ b/lib/Frontend/PCHWriterStmt.cpp
@@ -165,6 +165,7 @@ void PCHStmtWriter::VisitIfStmt(IfStmt *S) {
   Writer.WriteSubStmt(S->getThen());
   Writer.WriteSubStmt(S->getElse());
   Writer.AddSourceLocation(S->getIfLoc(), Record);
+  Writer.AddSourceLocation(S->getElseLoc(), Record);
   Code = pch::STMT_IF;
 }
 
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index e200c46e4f..a5277a9293 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -184,17 +184,20 @@ Sema::ActOnIfStmt(SourceLocation IfLoc, ExprArg CondVal,
 
   assert(condExpr && "ActOnIfStmt(): missing expression");
 
-  DefaultFunctionArrayConversion(condExpr);
-  // Take ownership again until we're past the error checking.
-  CondVal = condExpr;
-  QualType condType = condExpr->getType();
-
-  if (getLangOptions().CPlusPlus) {
-    if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4
-      return StmtError();
-  } else if (!condType->isScalarType()) // C99 6.8.4.1p1
-    return StmtError(Diag(IfLoc, diag::err_typecheck_statement_requires_scalar)
-      << condType << condExpr->getSourceRange());
+  if (!condExpr->isTypeDependent()) {
+    DefaultFunctionArrayConversion(condExpr);
+    // Take ownership again until we're past the error checking.
+    CondVal = condExpr;
+    QualType condType = condExpr->getType();
+    
+    if (getLangOptions().CPlusPlus) {
+      if (CheckCXXBooleanCondition(condExpr)) // C++ 6.4p4
+        return StmtError();
+    } else if (!condType->isScalarType()) // C99 6.8.4.1p1
+      return StmtError(Diag(IfLoc, 
+                            diag::err_typecheck_statement_requires_scalar)
+                       << condType << condExpr->getSourceRange());
+  }
 
   Stmt *thenStmt = ThenVal.takeAs<Stmt>();
 
@@ -209,7 +212,7 @@ Sema::ActOnIfStmt(SourceLocation IfLoc, ExprArg CondVal,
 
   CondVal.release();
   return Owned(new (Context) IfStmt(IfLoc, condExpr, thenStmt,
-                                    ElseVal.takeAs<Stmt>()));
+                                    ElseLoc, ElseVal.takeAs<Stmt>()));
 }
 
 Action::OwningStmtResult
diff --git a/lib/Sema/SemaTemplateInstantiateStmt.cpp b/lib/Sema/SemaTemplateInstantiateStmt.cpp
index cbe4449efc..957402ac6f 100644
--- a/lib/Sema/SemaTemplateInstantiateStmt.cpp
+++ b/lib/Sema/SemaTemplateInstantiateStmt.cpp
@@ -39,6 +39,7 @@ namespace {
     OwningStmtResult VisitDeclStmt(DeclStmt *S);
     OwningStmtResult VisitNullStmt(NullStmt *S);
     OwningStmtResult VisitCompoundStmt(CompoundStmt *S);
+    OwningStmtResult VisitIfStmt(IfStmt *S);
     OwningStmtResult VisitExpr(Expr *E);
     OwningStmtResult VisitLabelStmt(LabelStmt *S);
     OwningStmtResult VisitGotoStmt(GotoStmt *S);
@@ -135,6 +136,26 @@ TemplateStmtInstantiator::VisitCompoundStmt(CompoundStmt *S) {
                                               S->getRBracLoc()));
 }
 
+Sema::OwningStmtResult TemplateStmtInstantiator::VisitIfStmt(IfStmt *S) {
+  // Instantiate the condition
+  OwningExprResult Cond = SemaRef.InstantiateExpr(S->getCond(), TemplateArgs);
+  if (Cond.isInvalid())
+    return SemaRef.StmtError();
+
+  // Instantiate the "then" branch.
+  OwningStmtResult Then = SemaRef.InstantiateStmt(S->getThen(), TemplateArgs);
+  if (Then.isInvalid())
+    return SemaRef.StmtError();
+
+  // Instantiate the "else" branch.
+  OwningStmtResult Else = SemaRef.InstantiateStmt(S->getElse(), TemplateArgs);
+  if (Else.isInvalid())
+    return SemaRef.StmtError();
+
+  return SemaRef.ActOnIfStmt(S->getIfLoc(), move(Cond), move(Then),
+                             S->getElseLoc(), move(Else));
+}
+
 Sema::OwningStmtResult TemplateStmtInstantiator::VisitExpr(Expr *E) {
   Sema::OwningExprResult Result = SemaRef.InstantiateExpr(E, TemplateArgs);
   if (Result.isInvalid())
diff --git a/test/SemaTemplate/instantiate-function-1.cpp b/test/SemaTemplate/instantiate-function-1.cpp
index 482b466e84..5ded6140a6 100644
--- a/test/SemaTemplate/instantiate-function-1.cpp
+++ b/test/SemaTemplate/instantiate-function-1.cpp
@@ -58,3 +58,20 @@ template<typename T> struct X5 {
 void test_X5(X5<Incomplete> x5); // okay!
 
 template struct X5<Incomplete>; // expected-note{{instantiation}}
+
+template<typename T, typename U, typename V> struct X6 {
+  U f(T t, U u, V v) {
+    // IfStmt
+    if (t > 0)
+      return u;
+    else
+      return v; // expected-error{{incompatible type}}
+  }
+};
+
+struct ConvertibleToInt {
+  operator int() const;
+};
+
+template struct X6<ConvertibleToInt, float, char>;
+template struct X6<bool, int, int*>; // expected-note{{instantiation}}