ffcf214b5d
When we construct a `NonParamVarRegion`, we canonicalize the decl to always use the same entity for consistency. At the moment that is the canonical decl - which is the first decl in the redecl chain. However, this can cause problems with tentative declarations and extern declarations if we declare an array with unknown bounds. Consider this C example: https://godbolt.org/z/Kdvr11EqY ```lang=C typedef typeof(sizeof(int)) size_t; size_t clang_analyzer_getExtent(const void *p); void clang_analyzer_dump(size_t n); extern const unsigned char extern_redecl[]; const unsigned char extern_redecl[] = { 1,2,3,4 }; const unsigned char tentative_redecl[]; const unsigned char tentative_redecl[] = { 1,2,3,4 }; const unsigned char direct_decl[] = { 1,2,3,4 }; void test_redeclaration_extent(void) { clang_analyzer_dump(clang_analyzer_getExtent(direct_decl)); // 4 clang_analyzer_dump(clang_analyzer_getExtent(extern_redecl)); // should be 4 instead of Unknown clang_analyzer_dump(clang_analyzer_getExtent(tentative_redecl)); // should be 4 instead of Unknown } ``` The `getType()` of the canonical decls for the forward declared globals, will return `IncompleteArrayType`, unlike the `getDefinition()->getType()`, which would have returned `ConstantArrayType` of 4 elements. This makes the `MemRegionManager::getStaticSize()` return `Unknown` as the extent for the array variables, leading to FNs. To resolve this, I think we should prefer the definition decl (if present) over the canonical decl when constructing `NonParamVarRegion`s. FYI The canonicalization of the decl was introduced by D57619 in 2019. Differential Revision: https://reviews.llvm.org/D154827
19 lines
779 B
C
19 lines
779 B
C
// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify %s
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typedef typeof(sizeof(int)) size_t;
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size_t clang_analyzer_getExtent(const void *p);
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void clang_analyzer_dump(size_t n);
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extern const unsigned char extern_redecl[];
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const unsigned char extern_redecl[] = { 1,2,3,4 };
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const unsigned char tentative_redecl[];
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const unsigned char tentative_redecl[] = { 1,2,3,4 };
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const unsigned char direct_decl[] = { 1,2,3,4 };
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void test_redeclaration_extent(void) {
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clang_analyzer_dump(clang_analyzer_getExtent(direct_decl)); // expected-warning {{4 S64b}}
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clang_analyzer_dump(clang_analyzer_getExtent(extern_redecl)); // expected-warning {{4 S64b}}
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clang_analyzer_dump(clang_analyzer_getExtent(tentative_redecl)); // expected-warning {{4 S64b}}
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}
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