From b2e2c1bd963a262ab00a8c958ac8c3dfc40ff871 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron@aaronballman.com>
Date: Fri, 24 Oct 2014 13:19:19 +0000
Subject: [PATCH] Report when a function-try-block does not return a value on
 all control paths. Fixed PR14620.

llvm-svn: 220557
---
 clang/lib/Sema/AnalysisBasedWarnings.cpp | 65 ++++++++++++++------------------
 clang/test/SemaCXX/return-noreturn.cpp   | 21 ++++++++++-
 2 files changed, 48 insertions(+), 38 deletions(-)

diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index f9b8616..4d3d3e3 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -530,44 +530,37 @@ static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
   if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
       return;
 
-  // FIXME: Function try block
-  if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
-    switch (CheckFallThrough(AC)) {
-      case UnknownFallThrough:
-        break;
+  SourceLocation LBrace = Body->getLocStart(), RBrace = Body->getLocEnd();
+  // Either in a function body compound statement, or a function-try-block.
+  switch (CheckFallThrough(AC)) {
+    case UnknownFallThrough:
+      break;
 
-      case MaybeFallThrough:
-        if (HasNoReturn)
-          S.Diag(Compound->getRBracLoc(),
-                 CD.diag_MaybeFallThrough_HasNoReturn);
-        else if (!ReturnsVoid)
-          S.Diag(Compound->getRBracLoc(),
-                 CD.diag_MaybeFallThrough_ReturnsNonVoid);
-        break;
-      case AlwaysFallThrough:
-        if (HasNoReturn)
-          S.Diag(Compound->getRBracLoc(),
-                 CD.diag_AlwaysFallThrough_HasNoReturn);
-        else if (!ReturnsVoid)
-          S.Diag(Compound->getRBracLoc(),
-                 CD.diag_AlwaysFallThrough_ReturnsNonVoid);
-        break;
-      case NeverFallThroughOrReturn:
-        if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
-          if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
-            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
-              << 0 << FD;
-          } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
-            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
-              << 1 << MD;
-          } else {
-            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn);
-          }
+    case MaybeFallThrough:
+      if (HasNoReturn)
+        S.Diag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
+      else if (!ReturnsVoid)
+        S.Diag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
+      break;
+    case AlwaysFallThrough:
+      if (HasNoReturn)
+        S.Diag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
+      else if (!ReturnsVoid)
+        S.Diag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
+      break;
+    case NeverFallThroughOrReturn:
+      if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
+        if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
+        } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
+        } else {
+          S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
         }
-        break;
-      case NeverFallThrough:
-        break;
-    }
+      }
+      break;
+    case NeverFallThrough:
+      break;
   }
 }
 
diff --git a/clang/test/SemaCXX/return-noreturn.cpp b/clang/test/SemaCXX/return-noreturn.cpp
index 174971c..61b45c5 100644
--- a/clang/test/SemaCXX/return-noreturn.cpp
+++ b/clang/test/SemaCXX/return-noreturn.cpp
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -fsyntax-only -verify -Wreturn-type -Wmissing-noreturn -Wno-unreachable-code -Wno-covered-switch-default
-// RUN: %clang_cc1 %s -fsyntax-only -std=c++11 -verify -Wreturn-type -Wmissing-noreturn -Wno-unreachable-code -Wno-covered-switch-default
+// RUN: %clang_cc1 %s -fsyntax-only -fcxx-exceptions -verify -Wreturn-type -Wmissing-noreturn -Wno-unreachable-code -Wno-covered-switch-default
+// RUN: %clang_cc1 %s -fsyntax-only -fcxx-exceptions -std=c++11 -verify -Wreturn-type -Wmissing-noreturn -Wno-unreachable-code -Wno-covered-switch-default
 
 // A destructor may be marked noreturn and should still influence the CFG.
 void pr6884_abort() __attribute__((noreturn));
@@ -245,3 +245,20 @@ namespace LambdaVsTemporaryDtor {
   } // ok, initialization of lambda does not return
 }
 #endif
+
+// Ensure that function-try-blocks also check for return values properly.
+int functionTryBlock1(int s) try {
+  return 0;
+} catch (...) {
+} // expected-warning {{control may reach end of non-void function}}
+
+int functionTryBlock2(int s) try {
+} catch (...) {
+  return 0;
+} // expected-warning {{control may reach end of non-void function}}
+
+int functionTryBlock3(int s) try {
+  return 0;
+} catch (...) {
+  return 0;
+} // ok, both paths return.
-- 
2.7.4