commit d64657f2989f0e1e279f1ad8a03f627b4b60f407
author Nico Weber <nicolasweber@gmx.de> Mon Mar 09 02:47:59 2015 +0000
committer Nico Weber <nicolasweber@gmx.de> Mon Mar 09 02:47:59 2015 +0000
tree 771755984c567efb57fd15d7c16b463fbd2501e7
parent 9af63b22a5e5e3f5dc921dc987ccf96dabb87b43

Warn when jumping out of a __finally block via continue, break, return, __leave.

Since continue, break, return are much more common than __finally, this tries
to keep the work for continue, break, return O(1).  Sema keeps a stack of active
__finally scopes (to do this, ActOnSEHFinally() is split into
ActOnStartSEHFinally() and ActOnFinishSEHFinally()), and the various jump
statements then check if the current __finally scope (if present) is deeper
than then destination scope of the jump.

The same warning for goto statements is still missing.

This is the moral equivalent of MSVC's C4532.

llvm-svn: 231623

clang/lib/Sema/SemaStmt.cpp

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index aaf29db..11ec4f5 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2428,6 +2428,14 @@
   return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
 }
 
+static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
+                                     const Scope &DestScope) {
+  if (!S.CurrentSEHFinally.empty() &&
+      DestScope.Contains(*S.CurrentSEHFinally.back())) {
+    S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
+  }
+}
+
 StmtResult
 Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
   Scope *S = CurScope->getContinueParent();
@@ -2435,6 +2443,7 @@
     // C99 6.8.6.2p1: A break shall appear only in or as a loop body.
     return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
   }
+  CheckJumpOutOfSEHFinally(*this, ContinueLoc, *S);
 
   return new (Context) ContinueStmt(ContinueLoc);
 }
@@ -2449,6 +2458,7 @@
   if (S->isOpenMPLoopScope())
     return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
                      << "break");
+  CheckJumpOutOfSEHFinally(*this, BreakLoc, *S);
 
   return new (Context) BreakStmt(BreakLoc);
 }
@@ -2908,6 +2918,8 @@
     CurScope->setNoNRVO();
   }
 
+  CheckJumpOutOfSEHFinally(*this, ReturnLoc, *CurScope->getFnParent());
+
   return R;
 }
 
@@ -3406,11 +3418,14 @@
   return SEHExceptStmt::Create(Context,Loc,FilterExpr,Block);
 }
 
-StmtResult
-Sema::ActOnSEHFinallyBlock(SourceLocation Loc,
-                           Stmt *Block) {
+void Sema::ActOnStartSEHFinallyBlock() {
+  CurrentSEHFinally.push_back(CurScope);
+}
+
+StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
   assert(Block);
-  return SEHFinallyStmt::Create(Context,Loc,Block);
+  CurrentSEHFinally.pop_back();
+  return SEHFinallyStmt::Create(Context, Loc, Block);
 }
 
 StmtResult
@@ -3420,6 +3435,7 @@
     SEHTryParent = SEHTryParent->getParent();
   if (!SEHTryParent)
     return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
+  CheckJumpOutOfSEHFinally(*this, Loc, *SEHTryParent);
 
   return new (Context) SEHLeaveStmt(Loc);
 }