Parsing MS pragma intrinsic

Parse pragma intrinsic, display warning if the function isn't a builtin
function in clang and suggest including intrin.h.

Patch by Albert Gutowski!

Reviewers: aaron.ballman, rnk

Subscribers: aaron.ballman, cfe-commits

Differential Revision: https://reviews.llvm.org/D23944

llvm-svn: 280825

1 files changed, 60 insertions, 0 deletions

diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
index bff5d1170fe..7ae03af2b16 100644
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -161,6 +161,12 @@ struct PragmaMSRuntimeChecksHandler : public EmptyPragmaHandler {
   PragmaMSRuntimeChecksHandler() : EmptyPragmaHandler("runtime_checks") {}
 };
 
+struct PragmaMSIntrinsicHandler : public PragmaHandler {
+  PragmaMSIntrinsicHandler() : PragmaHandler("intrinsic") {}
+  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                    Token &FirstToken) override;
+};
+
 }  // end namespace
 
 void Parser::initializePragmaHandlers() {
@@ -229,6 +235,8 @@ void Parser::initializePragmaHandlers() {
     PP.AddPragmaHandler(MSSection.get());
     MSRuntimeChecks.reset(new PragmaMSRuntimeChecksHandler());
     PP.AddPragmaHandler(MSRuntimeChecks.get());
+    MSIntrinsic.reset(new PragmaMSIntrinsicHandler());
+    PP.AddPragmaHandler(MSIntrinsic.get());
   }
 
   OptimizeHandler.reset(new PragmaOptimizeHandler(Actions));
@@ -297,6 +305,8 @@ void Parser::resetPragmaHandlers() {
     MSSection.reset();
     PP.RemovePragmaHandler(MSRuntimeChecks.get());
     MSRuntimeChecks.reset();
+    PP.RemovePragmaHandler(MSIntrinsic.get());
+    MSIntrinsic.reset();
   }
 
   PP.RemovePragmaHandler("STDC", FPContractHandler.get());
@@ -2127,3 +2137,53 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
   PP.EnterTokenStream(std::move(TokenArray), 1,
                       /*DisableMacroExpansion=*/false);
 }
+
+/// \brief Handle the Microsoft \#pragma intrinsic extension.
+///
+/// The syntax is:
+/// \code
+///  #pragma intrinsic(memset)
+///  #pragma intrinsic(strlen, memcpy)
+/// \endcode
+///
+/// Pragma intrisic tells the compiler to use a builtin version of the
+/// function. Clang does it anyway, so the pragma doesn't really do anything.
+/// Anyway, we emit a warning if the function specified in \#pragma intrinsic
+/// isn't an intrinsic in clang and suggest to include intrin.h.
+void PragmaMSIntrinsicHandler::HandlePragma(Preprocessor &PP,
+                                            PragmaIntroducerKind Introducer,
+                                            Token &Tok) {
+  PP.Lex(Tok);
+
+  if (Tok.isNot(tok::l_paren)) {
+    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_lparen)
+        << "intrinsic";
+    return;
+  }
+  PP.Lex(Tok);
+
+  bool SuggestIntrinH = !PP.isMacroDefined("__INTRIN_H");
+
+  while (Tok.is(tok::identifier)) {
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+    if (!II->getBuiltinID())
+      PP.Diag(Tok.getLocation(), diag::warn_pragma_intrinsic_builtin)
+          << II << SuggestIntrinH;
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::comma))
+      break;
+    PP.Lex(Tok);
+  }
+
+  if (Tok.isNot(tok::r_paren)) {
+    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_rparen)
+        << "intrinsic";
+    return;
+  }
+  PP.Lex(Tok);
+
+  if (Tok.isNot(tok::eod))
+    PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
+        << "intrinsic";
+}