llvm-capstone/clang/test/Analysis/malloc.cpp
Artem Dergachev 7d4694547a [analyzer] Escape pointers stored into top-level parameters with destructors.
Writing stuff into an argument variable is usually equivalent to writing stuff
to a local variable: it will have no effect outside of the function.
There's an important exception from this rule: if the argument variable has
a non-trivial destructor, the destructor would be invoked on
the parent stack frame, exposing contents of the otherwise dead
argument variable to the caller.

If such argument is the last place where a pointer is stored before the function
exits and the function is the one we've started our analysis from (i.e., we have
no caller context for it), we currently diagnose a leak. This is incorrect
because the destructor of the argument still has access to the pointer.
The destructor may deallocate the pointer or even pass it further.

Treat writes into such argument regions as "escapes" instead, suppressing
spurious memory leak reports but not messing with dead symbol removal.

Differential Revision: https://reviews.llvm.org/D60112

llvm-svn: 358321
2019-04-13 02:01:45 +00:00

167 lines
4.2 KiB
C++

// RUN: %clang_analyze_cc1 -w -analyzer-checker=core,alpha.deadcode.UnreachableCode,alpha.core.CastSize,unix.Malloc,cplusplus.NewDelete -analyzer-store=region -verify %s
// RUN: %clang_analyze_cc1 -triple i386-unknown-linux-gnu -w -analyzer-checker=core,alpha.deadcode.UnreachableCode,alpha.core.CastSize,unix.Malloc,cplusplus.NewDelete -analyzer-store=region -verify %s
// RUN: %clang_analyze_cc1 -w -analyzer-checker=core,alpha.deadcode.UnreachableCode,alpha.core.CastSize,unix.Malloc,cplusplus.NewDelete -analyzer-store=region -DTEST_INLINABLE_ALLOCATORS -verify %s
// RUN: %clang_analyze_cc1 -triple i386-unknown-linux-gnu -w -analyzer-checker=core,alpha.deadcode.UnreachableCode,alpha.core.CastSize,unix.Malloc,cplusplus.NewDelete -analyzer-store=region -DTEST_INLINABLE_ALLOCATORS -verify %s
#include "Inputs/system-header-simulator-cxx.h"
typedef __typeof(sizeof(int)) size_t;
void *malloc(size_t);
void free(void *);
void *realloc(void *ptr, size_t size);
void *calloc(size_t nmemb, size_t size);
char *strdup(const char *s);
void checkThatMallocCheckerIsRunning() {
malloc(4);
} // expected-warning{{leak}}
// Test for radar://11110132.
struct Foo {
mutable void* m_data;
Foo(void* data) : m_data(data) {}
};
Foo aFunction() {
return malloc(10);
}
// Assume that functions which take a function pointer can free memory even if
// they are defined in system headers and take the const pointer to the
// allocated memory. (radar://11160612)
// Test default parameter.
int const_ptr_and_callback_def_param(int, const char*, int n, void(*)(void*) = free);
void r11160612_3() {
char *x = (char*)malloc(12);
const_ptr_and_callback_def_param(0, x, 12);
}
int const_ptr_and_callback_def_param_null(int, const char*, int n, void(*)(void*) = 0);
void r11160612_no_callback() {
char *x = (char*)malloc(12);
const_ptr_and_callback_def_param_null(0, x, 12);
} // expected-warning{{leak}}
// Test member function pointer.
struct CanFreeMemory {
static void myFree(void*);
};
//This is handled because we look at the type of the parameter(not argument).
void r11160612_3(CanFreeMemory* p) {
char *x = (char*)malloc(12);
const_ptr_and_callback_def_param(0, x, 12, p->myFree);
}
namespace PR13751 {
class OwningVector {
void **storage;
size_t length;
public:
OwningVector();
~OwningVector();
void push_back(void *Item) {
storage[length++] = Item;
}
};
void testDestructors() {
OwningVector v;
v.push_back(malloc(4));
// no leak warning; freed in destructor
}
}
struct X { void *a; };
struct X get() {
struct X result;
result.a = malloc(4);
return result; // no-warning
}
// Ensure that regions accessible through a LazyCompoundVal trigger region escape.
// Malloc checker used to report leaks for the following two test cases.
struct Property {
char* getterName;
Property(char* n)
: getterName(n) {}
};
void append(Property x);
void appendWrapper(char *getterName) {
append(Property(getterName));
}
void foo(const char* name) {
char* getterName = strdup(name);
appendWrapper(getterName); // no-warning
}
struct NestedProperty {
Property prop;
NestedProperty(Property p)
: prop(p) {}
};
void appendNested(NestedProperty x);
void appendWrapperNested(char *getterName) {
appendNested(NestedProperty(Property(getterName)));
}
void fooNested(const char* name) {
char* getterName = strdup(name);
appendWrapperNested(getterName); // no-warning
}
namespace PR31226 {
struct b2 {
int f;
};
struct b1 : virtual b2 {
void m();
};
struct d : b1, b2 {
};
void f() {
d *p = new d();
p->m(); // no-crash // no-warning
}
}
// Allow __cxa_demangle to escape.
char* test_cxa_demangle(const char* sym) {
size_t funcnamesize = 256;
char* funcname = (char*)malloc(funcnamesize);
int status;
char* ret = abi::__cxa_demangle(sym, funcname, &funcnamesize, &status);
if (status == 0) {
funcname = ret;
}
return funcname; // no-warning
}
namespace argument_leak {
class A {
char *name;
public:
char *getName() {
if (!name) {
name = static_cast<char *>(malloc(10));
}
return name;
}
~A() {
if (name) {
delete[] name;
}
}
};
void test(A a) {
(void)a.getName();
}
} // namespace argument_leak