commit 56ae0a67e8207e39b45ea9f19c6855a925189bb4
author Richard Smith <richard-llvm@metafoo.co.uk> Sat Jan 13 05:05:45 2018 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Sat Jan 13 05:05:45 2018 +0000
tree 888ed7e16a56df27af3fe0350e3efb619e954d98
parent b22d170caf3d2e344cb51ded85c9f52dafaad9f3

DR126: partially implement the const-correct rules for exception handler matching.

While here, fix up the myriad other ways in which Sema's two "can this handler
catch that exception?" implementations get things wrong and unify them.

llvm-svn: 322431

clang/lib/Sema/AnalysisBasedWarnings.cpp

diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 0033edf..e67f94c 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -287,48 +287,21 @@
   FoundPathWithNoThrowOutFunction,
 };
 
-static bool isThrowCaught(const CXXThrowExpr *Throw,
-                          const CXXCatchStmt *Catch) {
-  const Type *CaughtType = Catch->getCaughtType().getTypePtrOrNull();
-  if (!CaughtType)
-    return true;
-  const Type *ThrowType = nullptr;
-  if (Throw->getSubExpr())
-    ThrowType = Throw->getSubExpr()->getType().getTypePtrOrNull();
-  if (!ThrowType)
-    return false;
-  if (ThrowType->isReferenceType())
-    ThrowType = ThrowType->castAs<ReferenceType>()
-                    ->getPointeeType()
-                    ->getUnqualifiedDesugaredType();
-  if (CaughtType->isReferenceType())
-    CaughtType = CaughtType->castAs<ReferenceType>()
-                     ->getPointeeType()
-                     ->getUnqualifiedDesugaredType();
-  if (ThrowType->isPointerType() && CaughtType->isPointerType()) {
-    ThrowType = ThrowType->getPointeeType()->getUnqualifiedDesugaredType();
-    CaughtType = CaughtType->getPointeeType()->getUnqualifiedDesugaredType();
-  }
-  if (CaughtType == ThrowType)
-    return true;
-  const CXXRecordDecl *CaughtAsRecordType =
-      CaughtType->getAsCXXRecordDecl();
-  const CXXRecordDecl *ThrowTypeAsRecordType = ThrowType->getAsCXXRecordDecl();
-  if (CaughtAsRecordType && ThrowTypeAsRecordType)
-    return ThrowTypeAsRecordType->isDerivedFrom(CaughtAsRecordType);
-  return false;
-}
-
-static bool isThrowCaughtByHandlers(const CXXThrowExpr *CE,
+static bool isThrowCaughtByHandlers(Sema &S,
+                                    const CXXThrowExpr *CE,
                                     const CXXTryStmt *TryStmt) {
   for (unsigned H = 0, E = TryStmt->getNumHandlers(); H < E; ++H) {
-    if (isThrowCaught(CE, TryStmt->getHandler(H)))
+    QualType Caught = TryStmt->getHandler(H)->getCaughtType();
+    if (Caught.isNull() || // catch (...) catches everything
+        (CE->getSubExpr() && // throw; is only caught by ...
+         S.handlerCanCatch(Caught, CE->getSubExpr()->getType())))
       return true;
   }
   return false;
 }
 
-static bool doesThrowEscapePath(CFGBlock Block, SourceLocation &OpLoc) {
+static bool doesThrowEscapePath(Sema &S, CFGBlock Block,
+                                SourceLocation &OpLoc) {
   for (const auto &B : Block) {
     if (B.getKind() != CFGElement::Statement)
       continue;
@@ -342,7 +315,7 @@
         continue;
       if (const auto *Terminator =
               dyn_cast_or_null<CXXTryStmt>(I->getTerminator()))
-        if (isThrowCaughtByHandlers(CE, Terminator))
+        if (isThrowCaughtByHandlers(S, CE, Terminator))
           return false;
     }
     return true;
@@ -350,8 +323,8 @@
   return false;
 }
 
-static bool hasThrowOutNonThrowingFunc(SourceLocation &OpLoc, CFG *BodyCFG) {
-
+static bool hasThrowOutNonThrowingFunc(Sema &S, SourceLocation &OpLoc,
+                                       CFG *BodyCFG) {
   unsigned ExitID = BodyCFG->getExit().getBlockID();
 
   SmallVector<ThrowState, 16> States(BodyCFG->getNumBlockIDs(),
@@ -369,7 +342,7 @@
       if (ExitID == ID)
         continue;
 
-      if (doesThrowEscapePath(*CurBlock, OpLoc))
+      if (doesThrowEscapePath(S, *CurBlock, OpLoc))
         CurState = FoundPathForThrow;
     }
 
@@ -419,7 +392,7 @@
   if (BodyCFG->getExit().pred_empty())
     return;
   SourceLocation OpLoc;
-  if (hasThrowOutNonThrowingFunc(OpLoc, BodyCFG))
+  if (hasThrowOutNonThrowingFunc(S, OpLoc, BodyCFG))
     EmitDiagForCXXThrowInNonThrowingFunc(S, OpLoc, FD);
 }