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Revert "Revert "[analyzer] Ignore IncompleteArrayTypes in getStaticSize() for FAMs"" 

This reverts commit df1f4e0cc6.

Now the test case explicitly specifies the target triple.
I decided to use x86_64 for that matter, to have a fixed
bitwidth for `size_t`.

Aside from that, relanding the original changes of:
https://reviews.llvm.org/D105184
This commit is contained in:
Balazs Benics 2021-08-25 16:47:13 +02:00
parent 5f848b311f
commit e5646b9254
2 changed files with 114 additions and 5 deletions
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21
clang/lib/StaticAnalyzer/Core/MemRegion.cpp
View File

@ -768,14 +768,27 @@ DefinedOrUnknownSVal MemRegionManager::getStaticSize(const MemRegion *MR,
return UnknownVal();
QualType Ty = cast<TypedValueRegion>(SR)->getDesugaredValueType(Ctx);
DefinedOrUnknownSVal Size = getElementExtent(Ty, SVB);
const DefinedOrUnknownSVal Size = getElementExtent(Ty, SVB);
// A zero-length array at the end of a struct often stands for dynamically
// allocated extra memory.
if (Size.isZeroConstant()) {
if (isa<ConstantArrayType>(Ty))
return UnknownVal();
const auto isFlexibleArrayMemberCandidate = [this](QualType Ty) -> bool {
const ArrayType *AT = Ctx.getAsArrayType(Ty);
if (!AT)
return false;
if (isa<IncompleteArrayType>(AT))
return true;
if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
const llvm::APInt &Size = CAT->getSize();
if (Size.isNullValue())
return true;
}
return false;
};
if (isFlexibleArrayMemberCandidate(Ty))
return UnknownVal();
return Size;
}

96
clang/test/Analysis/flexible-array-members.c Normal file
View File

@ -0,0 +1,96 @@
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c90
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c99
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c11
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c17
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++98 -x c++
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++03 -x c++
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++11 -x c++
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++14 -x c++
// RUN: %clang_analyze_cc1 -triple x86_64-linux-gnu -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++17 -x c++
typedef __typeof(sizeof(int)) size_t;
size_t clang_analyzer_getExtent(void *);
void clang_analyzer_dump(size_t);
void *alloca(size_t size);
void *malloc(size_t size);
void free(void *ptr);
void test_incomplete_array_fam() {
typedef struct FAM {
char c;
int data[];
} FAM;
FAM fam;
clang_analyzer_dump(clang_analyzer_getExtent(&fam));
clang_analyzer_dump(clang_analyzer_getExtent(fam.data));
// expected-warning@-2 {{4 S64b}}
// expected-warning@-2 {{Unknown}}
FAM *p = (FAM *)alloca(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(p));
clang_analyzer_dump(clang_analyzer_getExtent(p->data));
// expected-warning@-2 {{4 U64b}}
// expected-warning@-2 {{Unknown}}
FAM *q = (FAM *)malloc(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(q));
clang_analyzer_dump(clang_analyzer_getExtent(q->data));
// expected-warning@-2 {{4 U64b}}
// expected-warning@-2 {{Unknown}}
free(q);
}
void test_zero_length_array_fam() {
typedef struct FAM {
char c;
int data[0];
} FAM;
FAM fam;
clang_analyzer_dump(clang_analyzer_getExtent(&fam));
clang_analyzer_dump(clang_analyzer_getExtent(fam.data));
// expected-warning@-2 {{4 S64b}}
// expected-warning@-2 {{Unknown}}
FAM *p = (FAM *)alloca(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(p));
clang_analyzer_dump(clang_analyzer_getExtent(p->data));
// expected-warning@-2 {{4 U64b}}
// expected-warning@-2 {{Unknown}}
FAM *q = (FAM *)malloc(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(q));
clang_analyzer_dump(clang_analyzer_getExtent(q->data));
// expected-warning@-2 {{4 U64b}}
// expected-warning@-2 {{Unknown}}
free(q);
}
void test_single_element_array_possible_fam() {
typedef struct FAM {
char c;
int data[1];
} FAM;
FAM likely_fam;
clang_analyzer_dump(clang_analyzer_getExtent(&likely_fam));
clang_analyzer_dump(clang_analyzer_getExtent(likely_fam.data));
// expected-warning@-2 {{8 S64b}}
// expected-warning@-2 {{4 S64b}}
FAM *p = (FAM *)alloca(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(p));
clang_analyzer_dump(clang_analyzer_getExtent(p->data));
// expected-warning@-2 {{8 U64b}}
// expected-warning@-2 {{4 S64b}}
FAM *q = (FAM *)malloc(sizeof(FAM));
clang_analyzer_dump(clang_analyzer_getExtent(q));
clang_analyzer_dump(clang_analyzer_getExtent(q->data));
// expected-warning@-2 {{8 U64b}}
// expected-warning@-2 {{4 S64b}}
free(q);
}