SEH: Track users of __try so we can pick a per-func EH personality

There are four major kinds of declarations that cause code generation:
- FunctionDecl (includes CXXMethodDecl etc)
- ObjCMethodDecl
- BlockDecl
- CapturedDecl

This patch tracks __try usage on FunctionDecls and diagnoses __try usage
in other decls. If someone wants to use __try from ObjC, they can use it
from a free function, since the ObjC code will need an ObjC-style EH
personality.

Eventually we will want to look through CapturedDecls and track SEH
usage on the parent FunctionDecl, if present.

llvm-svn: 228058

1 files changed, 24 insertions, 9 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index d17cf227011..4761c32f78d 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -3303,11 +3303,12 @@ StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
   if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
     Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
 
+  sema::FunctionScopeInfo *FSI = getCurFunction();
+
   // C++ try is incompatible with SEH __try.
-  if (!getLangOpts().Borland && getCurFunction()->FirstSEHTryLoc.isValid()) {
+  if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
     Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
-    Diag(getCurFunction()->FirstSEHTryLoc, diag::note_conflicting_try_here)
-        << "'__try'";
+    Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
   }
 
   const unsigned NumHandlers = Handlers.size();
@@ -3352,7 +3353,7 @@ StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
     }
   }
 
-  getCurFunction()->setHasCXXTry(TryLoc);
+  FSI->setHasCXXTry(TryLoc);
 
   // FIXME: We should detect handlers that cannot catch anything because an
   // earlier handler catches a superclass. Need to find a method that is not
@@ -3367,15 +3368,29 @@ StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
                                   Stmt *TryBlock, Stmt *Handler) {
   assert(TryBlock && Handler);
 
+  sema::FunctionScopeInfo *FSI = getCurFunction();
+
   // SEH __try is incompatible with C++ try. Borland appears to support this,
   // however.
-  if (!getLangOpts().Borland && getCurFunction()->FirstCXXTryLoc.isValid()) {
-    Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
-    Diag(getCurFunction()->FirstCXXTryLoc, diag::note_conflicting_try_here)
-        << "'try'";
+  if (!getLangOpts().Borland) {
+    if (FSI->FirstCXXTryLoc.isValid()) {
+      Diag(TryLoc, diag::err_mixing_cxx_try_seh_try);
+      Diag(FSI->FirstCXXTryLoc, diag::note_conflicting_try_here) << "'try'";
+    }
   }
 
-  getCurFunction()->setHasSEHTry(TryLoc);
+  FSI->setHasSEHTry(TryLoc);
+
+  // Reject __try in Obj-C methods, blocks, and captured decls, since we don't
+  // track if they use SEH.
+  DeclContext *DC = CurContext;
+  while (DC && !DC->isFunctionOrMethod())
+    DC = DC->getParent();
+  FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(DC);
+  if (FD)
+    FD->setUsesSEHTry(true);
+  else
+    Diag(TryLoc, diag::err_seh_try_outside_functions);
 
   return SEHTryStmt::Create(Context, IsCXXTry, TryLoc, TryBlock, Handler);
 }