[clang] Store FPOptions earlier when parsing function

[spavloff]

After #85605 ([clang] Set correct FPOptions if attribute 'optnone' presents) the current FP options in Sema are saved during parsing function because Sema can modify them if optnone is present. However they were saved too late, it caused fails in some cases when precompiled headers are used. This patch moves the storing earlier.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Serge Pavlov (spavloff)

Changes

After #85605 ([clang] Set correct FPOptions if attribute 'optnone' presents) the current FP options in Sema are saved during parsing function because Sema can modify them if optnone is present. However they were saved too late, it caused fails in some cases when precompiled headers are used. This patch moves the storing earlier.

---

Full diff: https://github.com/llvm/llvm-project/pull/92146.diff

2 Files Affected:

• (modified) clang/lib/Parse/Parser.cpp (+2-2)
• (added) clang/test/PCH/optnone.cpp (+6)

diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index adcbe5858bc78..869b9c6669c27 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1439,6 +1439,8 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
     }
   }
 
+  Sema::FPFeaturesStateRAII SaveFPFeatures(Actions);
+
   // Tell the actions module that we have entered a function definition with the
   // specified Declarator for the function.
   SkipBodyInfo SkipBody;
@@ -1497,8 +1499,6 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
     return Actions.ActOnFinishFunctionBody(Res, nullptr, false);
   }
 
-  Sema::FPFeaturesStateRAII SaveFPFeatures(Actions);
-
   if (Tok.is(tok::kw_try))
     return ParseFunctionTryBlock(Res, BodyScope);
 
diff --git a/clang/test/PCH/optnone.cpp b/clang/test/PCH/optnone.cpp
new file mode 100644
index 0000000000000..734527b0d3f7d
--- /dev/null
+++ b/clang/test/PCH/optnone.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -emit-pch -DHEADER -x c++-header %s -o %t.pch
+// RUN: %clang_cc1 -emit-llvm -include-pch %t.pch %s -o /dev/null
+
+#ifdef HEADER
+__attribute__((optnone)) void foo() {}
+#endif
\ No newline at end of file

[SLTozer]

I'm not familiar with the surrounding code, but this fixes the issue and looks reasonable.

[SLTozer]

It's not particularly important, but is there a reason for the use of the macros here?

[spavloff]

It is to avoid redefinition error. Funny, just this error was observed, because the macro also got into the precompiled header.

[SLTozer]

Ah, that makes sense since you're using a single file as the source and header - as does the resulting error. New test LGTM.