r325693 - [analyzer] Prevent AnalyzerStatsChecker from crash

[Peter Szecsi via cfe-commits]

Author: szepet
Date: Wed Feb 21 08:06:56 2018
New Revision: 325693

URL: http://llvm.org/viewvc/llvm-project?rev=325693&view=rev
Log:
[analyzer] Prevent AnalyzerStatsChecker from crash

The checker marks the locations where the analyzer creates sinks. However, it
can happen that the sink was created because of a loop which does not contain
condition statement, only breaks in the body. The exhausted block is the block
which should contain the condition but empty, in this case.
This change only emits this marking in order to avoid the undefined behavior.

Differential Revision: https://reviews.llvm.org/D42266


Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp
    cfe/trunk/test/Analysis/analyzer-stats.c

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp?rev=325693&r1=325692&r2=325693&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp Wed Feb 21 08:06:56 2018
@@ -122,6 +122,8 @@ void AnalyzerStatsChecker::checkEndAnaly
       E = CE.blocks_exhausted_end(); I != E; ++I) {
     const BlockEdge &BE =  I->first;
     const CFGBlock *Exit = BE.getDst();
+    if (Exit->empty())
+      continue;
     const CFGElement &CE = Exit->front();
     if (Optional<CFGStmt> CS = CE.getAs<CFGStmt>()) {
       SmallString<128> bufI;

Modified: cfe/trunk/test/Analysis/analyzer-stats.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/analyzer-stats.c?rev=325693&r1=325692&r2=325693&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/analyzer-stats.c (original)
+++ cfe/trunk/test/Analysis/analyzer-stats.c Wed Feb 21 08:06:56 2018
@@ -1,4 +1,4 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,deadcode.DeadStores,debug.Stats -verify -Wno-unreachable-code -analyzer-opt-analyze-nested-blocks %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,deadcode.DeadStores,debug.Stats -verify -Wno-unreachable-code -analyzer-opt-analyze-nested-blocks -analyzer-max-loop 4 %s
 
 int foo();
 
@@ -12,3 +12,19 @@ int test() { // expected-warning-re{{tes
   a /= 4;
   return a;
 }
+
+
+int sink() // expected-warning-re{{sink -> Total CFGBlocks: {{[0-9]+}} | Unreachable CFGBlocks: 1 | Exhausted Block: yes | Empty WorkList: yes}}
+{
+  for (int i = 0; i < 10; ++i) // expected-warning {{(sink): The analyzer generated a sink at this point}}
+    ++i;
+
+  return 0;
+}
+
+int emptyConditionLoop() // expected-warning-re{{emptyConditionLoop -> Total CFGBlocks: {{[0-9]+}} | Unreachable CFGBlocks: 0 | Exhausted Block: yes | Empty WorkList: yes}}
+{
+  int num = 1;
+  for (;;)
+    num++;
+}