vabridgers updated this revision to Diff 267882.
vabridgers added a comment.
Address comments from Artem and Balazs. This change just avoids the crash for
now until a proper fix can be made.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D80903/new/
https://reviews.llvm.org/D80903
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
@@ -137,3 +137,17 @@
clang_analyzer_eval(clang_analyzer_getExtent(&vla3m) == 2 * x * 4 *
sizeof(int));
// expected-warning@-1{{TRUE}}
}
+
+// https://bugs.llvm.org/show_bug.cgi?id=46128
+// analyzer doesn't handle more than simple symbolic expressions.
+// Just don't crash.
+extern void foo(void);
+int a;
+void b() {
+ int c = a + 1;
+ for (;;) {
+ int d[c];
+ for (; 0 < c;)
+ foo();
+ }
+} // no-crash
Index: clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -126,7 +126,12 @@
// Size overflow check does not work with symbolic expressions because a
// overflow situation can not be detected easily.
uint64_t IndexL = IndexLVal->getZExtValue();
- assert(IndexL > 0 && "Index length should have been checked for zero.");
+ // FIXME: See https://reviews.llvm.org/D80903 for discussion of
+ // some difference in assume and getKnownValue that leads to
+ // unexpected behavior. Just bail on IndexL == 0 at this point.
+ if (IndexL == 0)
+ return nullptr;
+
if (KnownSize <= SizeMax / IndexL) {
KnownSize *= IndexL;
} else {
Index: clang/test/Analysis/vla.c
===================================================================
--- clang/test/Analysis/vla.c
+++ clang/test/Analysis/vla.c
@@ -137,3 +137,17 @@
clang_analyzer_eval(clang_analyzer_getExtent(&vla3m) == 2 * x * 4 * sizeof(int));
// expected-warning@-1{{TRUE}}
}
+
+// https://bugs.llvm.org/show_bug.cgi?id=46128
+// analyzer doesn't handle more than simple symbolic expressions.
+// Just don't crash.
+extern void foo(void);
+int a;
+void b() {
+ int c = a + 1;
+ for (;;) {
+ int d[c];
+ for (; 0 < c;)
+ foo();
+ }
+} // no-crash
Index: clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -126,7 +126,12 @@
// Size overflow check does not work with symbolic expressions because a
// overflow situation can not be detected easily.
uint64_t IndexL = IndexLVal->getZExtValue();
- assert(IndexL > 0 && "Index length should have been checked for zero.");
+ // FIXME: See https://reviews.llvm.org/D80903 for discussion of
+ // some difference in assume and getKnownValue that leads to
+ // unexpected behavior. Just bail on IndexL == 0 at this point.
+ if (IndexL == 0)
+ return nullptr;
+
if (KnownSize <= SizeMax / IndexL) {
KnownSize *= IndexL;
} else {
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