Preprocessor: Ignore unknown pragmas in -E -dM and -Eonly modes.

llvm-svn: 105830

5 files changed, 28 insertions, 0 deletions

diff --git a/clang/include/clang/Lex/Pragma.h b/clang/include/clang/Lex/Pragma.h
index ef367feb84d..52f01a9a976 100644
--- a/clang/include/clang/Lex/Pragma.h
+++ b/clang/include/clang/Lex/Pragma.h
@@ -46,6 +46,15 @@ public:
   virtual PragmaNamespace *getIfNamespace() { return 0; }
 };
 
+/// EmptyPragmaHandler - A pragma handler which takes no action, which can be
+/// used to ignore particular pragmas.
+class EmptyPragmaHandler : public PragmaHandler {
+public:
+  EmptyPragmaHandler();
+
+  virtual void HandlePragma(Preprocessor &PP, Token &FirstToken);
+};
+
 /// PragmaNamespace - This PragmaHandler subdivides the namespace of pragmas,
 /// allowing hierarchical pragmas to be defined.  Common examples of namespaces
 /// are "#pragma GCC", "#pragma STDC", and "#pragma omp", but any namespaces may
diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp
index 6cd960be20d..421d69d2430 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -9,6 +9,7 @@
 
 #include "clang/Frontend/FrontendActions.h"
 #include "clang/AST/ASTConsumer.h"
+#include "clang/Lex/Pragma.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Parse/Parser.h"
 #include "clang/Basic/FileManager.h"
@@ -223,6 +224,9 @@ void ParseOnlyAction::ExecuteAction() {
 void PreprocessOnlyAction::ExecuteAction() {
   Preprocessor &PP = getCompilerInstance().getPreprocessor();
 
+  // Ignore unknown pragmas.
+  PP.AddPragmaHandler(0, new EmptyPragmaHandler());
+
   Token Tok;
   // Start parsing the specified input file.
   PP.EnterMainSourceFile();
diff --git a/clang/lib/Frontend/PrintPreprocessedOutput.cpp b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
index b6c18b77316..e89c425f470 100644
--- a/clang/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/clang/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -454,6 +454,9 @@ static int MacroIDCompare(const void* a, const void* b) {
 }
 
 static void DoPrintMacros(Preprocessor &PP, llvm::raw_ostream *OS) {
+  // Ignore unknown pragmas.
+  PP.AddPragmaHandler(0, new EmptyPragmaHandler());
+
   // -dM mode just scans and ignores all tokens in the files, then dumps out
   // the macro table at the end.
   PP.EnterMainSourceFile();
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 92332a00686..58a632618fd 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -27,6 +27,14 @@ PragmaHandler::~PragmaHandler() {
 }
 
 //===----------------------------------------------------------------------===//
+// EmptyPragmaHandler Implementation.
+//===----------------------------------------------------------------------===//
+
+EmptyPragmaHandler::EmptyPragmaHandler() : PragmaHandler(0) {}
+
+void EmptyPragmaHandler::HandlePragma(Preprocessor &PP, Token &FirstToken) {}
+
+//===----------------------------------------------------------------------===//
 // PragmaNamespace Implementation.
 //===----------------------------------------------------------------------===//
 
diff --git a/clang/test/Frontend/unknown-pragmas.c b/clang/test/Frontend/unknown-pragmas.c
new file mode 100644
index 00000000000..53a5a45a433
--- /dev/null
+++ b/clang/test/Frontend/unknown-pragmas.c
@@ -0,0 +1,4 @@
+// RUN: %clang_cc1 -Eonly -Wall -verify %s
+// RUN: %clang_cc1 -E -dM -Wall -verify %s
+
+#pragma adgohweopihweotnwet