vabridgers created this revision.
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Szelethus, gamesh411.
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See https://bugs.llvm.org/show_bug.cgi?id=47272. The checker does not
yet comprehend constraints involving multiple symbols, so it's
possible to calculate a VLA size that's causes an assert. A LIT is added to
catch regressions, and this change simply bails if a size is calculated
that is not known.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D86743
Files:
clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
clang/test/Analysis/vla.c
Index: clang/test/Analysis/vla.c
===================================================================
--- clang/test/Analysis/vla.c
+++ clang/test/Analysis/vla.c
@@ -151,3 +151,22 @@
foo();
}
} // no-crash
+
+
+// https://bugs.llvm.org/show_bug.cgi?id=47272
+// similar to the above case, just different enough to have not
+// been covered.
+// Just don't crash.
+int bb;
+int c() {
+ int d = 0;
+ int sum = 0;
+ while (bb) {
+ int count = bb - d;
+ int e[count];
+ if (count > 4)
+ sum++;
+ d++;
+ }
+ return sum;
+} // no-crash
Index: clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -298,8 +298,11 @@
DefinedOrUnknownSVal SizeIsKnown = SVB.evalEQ(State, DynSize,
*ArraySizeNL);
State = State->assume(SizeIsKnown, true);
- // Assume should not fail at this point.
- assert(State);
+ // State may not be valid since constraints do not comprehend expressions
+ // used for VLAs. If State is null, just silently return.
+ // See https://bugs.llvm.org/show_bug.cgi?id=47272.
+ if (!State)
+ return;
}
// Remember our assumptions!
Index: clang/test/Analysis/vla.c
===================================================================
--- clang/test/Analysis/vla.c
+++ clang/test/Analysis/vla.c
@@ -151,3 +151,22 @@
foo();
}
} // no-crash
+
+
+// https://bugs.llvm.org/show_bug.cgi?id=47272
+// similar to the above case, just different enough to have not
+// been covered.
+// Just don't crash.
+int bb;
+int c() {
+ int d = 0;
+ int sum = 0;
+ while (bb) {
+ int count = bb - d;
+ int e[count];
+ if (count > 4)
+ sum++;
+ d++;
+ }
+ return sum;
+} // no-crash
Index: clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -298,8 +298,11 @@
DefinedOrUnknownSVal SizeIsKnown = SVB.evalEQ(State, DynSize, *ArraySizeNL);
State = State->assume(SizeIsKnown, true);
- // Assume should not fail at this point.
- assert(State);
+ // State may not be valid since constraints do not comprehend expressions
+ // used for VLAs. If State is null, just silently return.
+ // See https://bugs.llvm.org/show_bug.cgi?id=47272.
+ if (!State)
+ return;
}
// Remember our assumptions!
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