Author: szelethus Date: Sun Jun 16 07:52:56 2019 New Revision: 363510 URL: http://llvm.org/viewvc/llvm-project?rev=363510&view=rev Log: [analyzer] Track indices of arrays
Often times, when an ArraySubscriptExpr was reported as null or undefined, the bug report was difficult to understand, because the analyzer explained why arr[i] has that value, but didn't realize that in fact i's value is very important as well. This patch fixes this by tracking the indices of arrays. Differential Revision: https://reviews.llvm.org/D63080 Modified: cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp cfe/trunk/test/Analysis/diagnostics/track_subexpressions.cpp Modified: cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp?rev=363510&r1=363509&r2=363510&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp Sun Jun 16 07:52:56 2019 @@ -1740,6 +1740,10 @@ bool bugreporter::trackExpressionValue(c if (const Expr *Receiver = NilReceiverBRVisitor::getNilReceiver(Inner, LVNode)) trackExpressionValue(LVNode, Receiver, report, EnableNullFPSuppression); + if (const auto *Arr = dyn_cast<ArraySubscriptExpr>(Inner)) + trackExpressionValue( + LVNode, Arr->getIdx(), report, EnableNullFPSuppression); + // See if the expression we're interested refers to a variable. // If so, we can track both its contents and constraints on its value. if (ExplodedGraph::isInterestingLValueExpr(Inner)) { Modified: cfe/trunk/test/Analysis/diagnostics/track_subexpressions.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/diagnostics/track_subexpressions.cpp?rev=363510&r1=363509&r2=363510&view=diff ============================================================================== --- cfe/trunk/test/Analysis/diagnostics/track_subexpressions.cpp (original) +++ cfe/trunk/test/Analysis/diagnostics/track_subexpressions.cpp Sun Jun 16 07:52:56 2019 @@ -17,3 +17,28 @@ void shift_by_undefined_value() { (void)(TCP_MAXWIN << shift_amount); // expected-warning{{The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'int'}} // expected-note@-1{{The result of the left shift is undefined due to shifting by '255', which is greater or equal to the width of type 'int'}} } + +namespace array_index_tracking { +void consume(int); + +int getIndex(int x) { + int a; + if (x > 0) + a = 3; + else + a = 2; + return a; +} + +int getInt(); + +void testArrayIndexTracking() { + int arr[10]; + + for (int i = 0; i < 3; ++i) + arr[i] = 0; + int x = getInt(); + int n = getIndex(x); + consume(arr[n]); +} +} // end of namespace array_index_tracking _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
