Add support for Microsoft __if_exists and __if_not_exists construct inside function definition.

Allow to include or exclude code depending on if a symbol exists or not. Just like a #ifdef but for C/C++ symbols.

More doc: http://msdn.microsoft.com/en-us/library/x7wy9xh3(v=VS.100).aspx

Support at class and namespace scopes will be added later.

llvm-svn: 131014

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 7f1bf596a23..e9aa1d3bcf8 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -4295,3 +4295,18 @@ StmtResult Sema::ActOnFinishFullStmt(Stmt *FullStmt) {
 
   return MaybeCreateStmtWithCleanups(FullStmt);
 }
+
+bool Sema::CheckMicrosoftIfExistsSymbol(CXXScopeSpec &SS,
+                                        UnqualifiedId &Name) {
+  DeclarationNameInfo TargetNameInfo = GetNameFromUnqualifiedId(Name);
+  DeclarationName TargetName = TargetNameInfo.getName();
+  if (!TargetName)
+    return false;
+
+  // Do the redeclaration lookup in the current scope.
+  LookupResult R(*this, TargetNameInfo, Sema::LookupAnyName,
+                 Sema::NotForRedeclaration);
+  R.suppressDiagnostics();
+  LookupParsedName(R, getCurScope(), &SS);
+  return !R.empty(); 
+}