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190449a5d2
Fix some false negatives of StackAddrEscapeChecker:
- Output parameters
```
void top(int **out) {
int local = 42;
*out = &local; // Noncompliant
}
```
- Indirect global pointers
```
int **global;
void top() {
int local = 42;
*global = &local; // Noncompliant
}
```
Note that now StackAddrEscapeChecker produces a diagnostic if a function
with an output parameter is analyzed as top-level or as a callee. I took
special care to make sure the reports point to the same primary location
and, in many cases, feature the same primary message. That is the
motivation to modify Core/BugReporter.cpp and Core/ExplodedGraph.cpp
To avoid false positive reports when a global indirect pointer is
assigned a local address, invalidated, and then reset, I rely on the
fact that the invalidation symbol will be a DerivedSymbol of a
ConjuredSymbol that refers to the same memory region.
The checker still has a false negative for non-trivial escaping via a
returned value. It requires a more sophisticated traversal akin to
scanReachableSymbols, which out of the scope of this change.
CPP-4734
---------
This is the last of the 3 stacked PRs, it must not be merged before
https://github.com/llvm/llvm-project/pull/105652 and
https://github.com/llvm/llvm-project/pull/105653
30 lines
730 B
C
30 lines
730 B
C
// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify %s
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void clang_analyzer_eval(int);
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void callee(void **p) {
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int x;
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*p = &x;
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// expected-warning@-1 {{Address of stack memory associated with local \
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variable 'x' is still referred to by the caller variable 'arr' upon \
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returning to the caller}}
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}
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void loop(void) {
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void *arr[2];
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for (int i = 0; i < 2; ++i)
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callee(&arr[i]);
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// FIXME: Should be UNKNOWN.
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clang_analyzer_eval(arr[0] == arr[1]); // expected-warning{{FALSE}}
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}
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void loopWithCall(void) {
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void *arr[2];
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for (int i = 0; i < 2; ++i) {
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int x;
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arr[i] = &x;
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}
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// FIXME: Should be UNKNOWN.
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clang_analyzer_eval(arr[0] == arr[1]); // expected-warning{{TRUE}}
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}
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