4 files changed, 59 insertions, 1 deletions
diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
index fb862c706f9..26b363f280c 100644
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -106,8 +106,19 @@ struct PragmaSTDC_FENV_ACCESSHandler : public PragmaHandler {
     tok::OnOffSwitch OOS;
     if (PP.LexOnOffSwitch(OOS))
      return;
-    if (OOS == tok::OOS_ON)
+    if (OOS == tok::OOS_ON) {
       PP.Diag(Tok, diag::warn_stdc_fenv_access_not_supported);
+    }
+
+    MutableArrayRef<Token> Toks(PP.getPreprocessorAllocator().Allocate<Token>(1),
+                                1);
+    Toks[0].startToken();
+    Toks[0].setKind(tok::annot_pragma_fenv_access);
+    Toks[0].setLocation(Tok.getLocation());
+    Toks[0].setAnnotationEndLoc(Tok.getLocation());
+    Toks[0].setAnnotationValue(reinterpret_cast<void*>(
+                               static_cast<uintptr_t>(OOS)));
+    PP.EnterTokenStream(Toks, /*DisableMacroExpansion=*/true);
   }
 };
 
@@ -604,6 +615,30 @@ void Parser::HandlePragmaFPContract() {
   ConsumeAnnotationToken();
 }
 
+void Parser::HandlePragmaFEnvAccess() {
+  assert(Tok.is(tok::annot_pragma_fenv_access));
+  tok::OnOffSwitch OOS =
+    static_cast<tok::OnOffSwitch>(
+    reinterpret_cast<uintptr_t>(Tok.getAnnotationValue()));
+
+  LangOptions::FEnvAccessModeKind FPC;
+  switch (OOS) {
+  case tok::OOS_ON:
+    FPC = LangOptions::FEA_On;
+    break;
+  case tok::OOS_OFF:
+    FPC = LangOptions::FEA_Off;
+    break;
+  case tok::OOS_DEFAULT: // FIXME: Add this cli option when it makes sense.
+    FPC = LangOptions::FEA_Off;
+    break;
+  }
+
+  Actions.ActOnPragmaFEnvAccess(FPC);
+  ConsumeAnnotationToken();
+}
+
+
 StmtResult Parser::HandlePragmaCaptured()
 {
   assert(Tok.is(tok::annot_pragma_captured));
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 338a8ab7e8a..574293f5181 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -348,6 +348,11 @@ Retry:
     ConsumeAnnotationToken();
     return StmtError();
 
+  case tok::annot_pragma_fenv_access:
+    ProhibitAttributes(Attrs);
+    HandlePragmaFEnvAccess();
+    return StmtEmpty();
+
   case tok::annot_pragma_opencl_extension:
     ProhibitAttributes(Attrs);
     HandlePragmaOpenCLExtension();
@@ -902,6 +907,9 @@ void Parser::ParseCompoundStatementLeadingPragmas() {
     case tok::annot_pragma_fp:
       HandlePragmaFP();
       break;
+    case tok::annot_pragma_fenv_access:
+      HandlePragmaFEnvAccess();
+      break;
     case tok::annot_pragma_ms_pointers_to_members:
       HandlePragmaMSPointersToMembers();
       break;
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index c3085654f52..17366291213 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -674,6 +674,9 @@ Parser::ParseExternalDeclaration(ParsedAttributesWithRange &attrs,
   case tok::annot_pragma_fp_contract:
     HandlePragmaFPContract();
     return nullptr;
+  case tok::annot_pragma_fenv_access:
+    HandlePragmaFEnvAccess();
+    return nullptr;
   case tok::annot_pragma_fp:
     HandlePragmaFP();
     break;
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 056d031fd83..8024e1a0515 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -773,6 +773,18 @@ void Sema::ActOnPragmaFPContract(LangOptions::FPContractModeKind FPC) {
   }
 }
 
+void Sema::ActOnPragmaFEnvAccess(LangOptions::FEnvAccessModeKind FPC) {
+  switch (FPC) {
+  case LangOptions::FEA_On:
+    FPFeatures.setAllowFEnvAccess();
+    break;
+  case LangOptions::FEA_Off:
+    FPFeatures.setDisallowFEnvAccess();
+    break;
+  }
+}
+
+
 void Sema::PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
                                        SourceLocation Loc) {
   // Visibility calculations will consider the namespace's visibility.