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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
21 lines
1.1 KiB
C++
21 lines
1.1 KiB
C++
// RUN: %clang_analyze_cc1 -verify %s -fblocks \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-output=text
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int* stack_addr_escape_base() {
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int x = 0;
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// FIXME: This shouldn't be tied to a modeling checker.
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return &x; // expected-warning{{Address of stack memory associated with local variable 'x' returned to caller [core.StackAddressEscape]}}
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// expected-note-re@-1{{{{^Address of stack memory associated with local variable 'x' returned to caller$}}}}
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// Just a regular compiler warning.
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// expected-warning@-3{{address of stack memory associated with local variable 'x' returned}}
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}
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char const *p;
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void f0() {
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char const str[] = "This will change";
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p = str;
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} // expected-warning@-1{{Address of stack memory associated with local variable 'str' is still referred to by the global variable 'p' upon returning to the caller. This will be a dangling reference [core.StackAddressEscape]}}
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// expected-note@-2{{Address of stack memory associated with local variable 'str' is still referred to by the global variable 'p' upon returning to the caller. This will be a dangling reference}}
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