Discourse mail: https://discourse.llvm.org/t/analyzer-why-do-we-suck-at-modeling-c-dynamic-memory/65667 malloc() returns a piece of uninitialized dynamic memory. We were (almost) always able to model this behaviour. Its C++ counterpart, operator new is a lot more complex, because it allows for initialization, the most complicated of which is the usage of constructors. We gradually became better in modeling constructors, but for some reason, most likely for reasons lost in history, we never actually modeled the case when the memory returned by operator new was just simply uninitialized. This patch (attempts) to fix this tiny little error. Differential Revision: https://reviews.llvm.org/D135375
461 lines
11 KiB
C++
461 lines
11 KiB
C++
// RUN: %clang_analyze_cc1 -std=c++11 -fblocks %s \
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// RUN: -verify=expected,newdelete \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDelete
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//
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// RUN: %clang_analyze_cc1 -DLEAKS -std=c++11 -fblocks %s \
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// RUN: -verify=expected,newdelete,leak \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDelete \
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// RUN: -analyzer-checker=cplusplus.NewDeleteLeaks
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//
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// RUN: %clang_analyze_cc1 -std=c++11 -fblocks -verify %s \
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// RUN: -verify=expected,leak \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDeleteLeaks
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//
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// RUN: %clang_analyze_cc1 -std=c++17 -fblocks %s \
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// RUN: -verify=expected,newdelete \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDelete
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//
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// RUN: %clang_analyze_cc1 -DLEAKS -std=c++17 -fblocks %s \
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// RUN: -verify=expected,newdelete,leak \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDelete \
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// RUN: -analyzer-checker=cplusplus.NewDeleteLeaks
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//
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// RUN: %clang_analyze_cc1 -std=c++17 -fblocks -verify %s \
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// RUN: -verify=expected,leak \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=cplusplus.NewDeleteLeaks
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#include "Inputs/system-header-simulator-cxx.h"
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typedef __typeof__(sizeof(int)) size_t;
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extern "C" void *malloc(size_t);
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extern "C" void free (void* ptr);
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int *global;
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//------------------
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// check for leaks
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//------------------
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//----- Standard non-placement operators
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void testGlobalOpNew() {
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void *p = operator new(0);
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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void testGlobalOpNewArray() {
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void *p = operator new[](0);
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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void testGlobalNewExpr() {
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int *p = new int;
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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void testGlobalNewExprArray() {
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int *p = new int[0];
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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//----- Standard nothrow placement operators
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void testGlobalNoThrowPlacementOpNewBeforeOverload() {
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void *p = operator new(0, std::nothrow);
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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void testGlobalNoThrowPlacementExprNewBeforeOverload() {
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int *p = new(std::nothrow) int;
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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//----- Standard pointer placement operators
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void testGlobalPointerPlacementNew() {
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int i;
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void *p1 = operator new(0, &i); // no warn
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void *p2 = operator new[](0, &i); // no warn
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int *p3 = new(&i) int; // no warn
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int *p4 = new(&i) int[0]; // no warn
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}
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//----- Other cases
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void testNewMemoryIsInHeap() {
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int *p = new int;
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if (global != p) // condition is always true as 'p' wraps a heap region that
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// is different from a region wrapped by 'global'
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global = p; // pointer escapes
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}
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struct PtrWrapper {
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int *x;
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PtrWrapper(int *input) : x(input) {}
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};
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void testNewInvalidationPlacement(PtrWrapper *w) {
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// Ensure that we don't consider this a leak.
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new (w) PtrWrapper(new int); // no warn
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}
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//-----------------------------------------
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// check for usage of zero-allocated memory
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//-----------------------------------------
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void testUseZeroAlloc1() {
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int *p = (int *)operator new(0);
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*p = 1; // newdelete-warning {{Use of memory allocated with size zero}}
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delete p;
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}
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int testUseZeroAlloc2() {
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int *p = (int *)operator new[](0);
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return p[0]; // newdelete-warning {{Use of memory allocated with size zero}}
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delete[] p;
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}
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void f(int);
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void testUseZeroAlloc3() {
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int *p = new int[0];
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f(*p); // newdelete-warning {{Use of memory allocated with size zero}}
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delete[] p;
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}
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//---------------
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// other checks
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//---------------
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class SomeClass {
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public:
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void f(int *p);
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};
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void f(int *p1, int *p2 = 0, int *p3 = 0);
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void g(SomeClass &c, ...);
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void testUseFirstArgAfterDelete() {
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int *p = new int;
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delete p;
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f(p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseMiddleArgAfterDelete(int *p) {
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delete p;
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f(0, p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseLastArgAfterDelete(int *p) {
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delete p;
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f(0, 0, p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseSeveralArgsAfterDelete(int *p) {
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delete p;
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f(p, p, p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseRefArgAfterDelete(SomeClass &c) {
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delete &c;
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g(c); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testVariadicArgAfterDelete() {
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SomeClass c;
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int *p = new int;
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delete p;
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g(c, 0, p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseMethodArgAfterDelete(int *p) {
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SomeClass *c = new SomeClass;
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delete p;
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c->f(p); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testUseThisAfterDelete() {
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SomeClass *c = new SomeClass;
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delete c;
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c->f(0); // newdelete-warning{{Use of memory after it is freed}}
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}
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void testDoubleDelete() {
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int *p = new int;
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delete p;
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delete p; // newdelete-warning{{Attempt to free released memory}}
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}
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void testExprDeleteArg() {
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int i;
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delete &i; // newdelete-warning{{Argument to 'delete' is the address of the local variable 'i', which is not memory allocated by 'new'}}
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}
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void testExprDeleteArrArg() {
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int i;
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delete[] & i; // newdelete-warning{{Argument to 'delete[]' is the address of the local variable 'i', which is not memory allocated by 'new[]'}}
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}
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void testAllocDeallocNames() {
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int *p = new(std::nothrow) int[1];
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delete[] (++p);
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// newdelete-warning@-1{{Argument to 'delete[]' is offset by 4 bytes from the start of memory allocated by 'new[]'}}
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}
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//--------------------------------
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// Test escape of newed const pointer. Note, a const pointer can be deleted.
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//--------------------------------
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struct StWithConstPtr {
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const int *memp;
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};
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void escape(const int &x);
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void escapeStruct(const StWithConstPtr &x);
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void escapePtr(const StWithConstPtr *x);
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void escapeVoidPtr(const void *x);
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void testConstEscape() {
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int *p = new int(1);
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escape(*p);
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} // no-warning
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void testConstEscapeStruct() {
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StWithConstPtr *St = new StWithConstPtr();
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escapeStruct(*St);
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} // no-warning
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void testConstEscapeStructPtr() {
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StWithConstPtr *St = new StWithConstPtr();
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escapePtr(St);
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} // no-warning
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void testConstEscapeMember() {
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StWithConstPtr St;
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St.memp = new int(2);
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escapeVoidPtr(St.memp);
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} // no-warning
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void testConstEscapePlacementNew() {
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int *x = (int *)malloc(sizeof(int));
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void *y = new (x) int;
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escapeVoidPtr(y);
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} // no-warning
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//============== Test Uninitialized delete delete[]========================
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void testUninitDelete() {
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int *x;
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int * y = new int;
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delete y;
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delete x; // expected-warning{{Argument to 'delete' is uninitialized}}
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}
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void testUninitDeleteArray() {
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int *x;
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int * y = new int[5];
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delete[] y;
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delete[] x; // expected-warning{{Argument to 'delete[]' is uninitialized}}
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}
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void testUninitFree() {
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int *x;
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free(x); // expected-warning{{1st function call argument is an uninitialized value}}
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}
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void testUninitDeleteSink() {
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int *x;
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delete x; // expected-warning{{Argument to 'delete' is uninitialized}}
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(*(volatile int *)0 = 1); // no warn
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}
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void testUninitDeleteArraySink() {
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int *x;
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delete[] x; // expected-warning{{Argument to 'delete[]' is uninitialized}}
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(*(volatile int *)0 = 1); // no warn
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}
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namespace reference_count {
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class control_block {
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unsigned count;
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public:
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control_block() : count(0) {}
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void retain() { ++count; }
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int release() { return --count; }
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};
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template <typename T>
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class shared_ptr {
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T *p;
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control_block *control;
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public:
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shared_ptr() : p(0), control(0) {}
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explicit shared_ptr(T *p) : p(p), control(new control_block) {
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control->retain();
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}
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shared_ptr(const shared_ptr &other) : p(other.p), control(other.control) {
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if (control)
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control->retain();
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}
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~shared_ptr() {
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if (control && control->release() == 0) {
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delete p;
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delete control;
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}
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};
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T &operator *() {
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return *p;
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};
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void swap(shared_ptr &other) {
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T *tmp = p;
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p = other.p;
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other.p = tmp;
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control_block *ctrlTmp = control;
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control = other.control;
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other.control = ctrlTmp;
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}
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};
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template <typename T, typename... Args>
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shared_ptr<T> make_shared(Args &&...args) {
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return shared_ptr<T>(new T(static_cast<Args &&>(args)...));
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}
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void testSingle() {
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shared_ptr<int> a(new int);
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*a = 1;
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}
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void testMake() {
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shared_ptr<int> a = make_shared<int>();
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*a = 1;
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}
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void testMakeInParens() {
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shared_ptr<int> a = (make_shared<int>()); // no warn
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*a = 1;
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}
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void testDouble() {
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shared_ptr<int> a(new int);
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shared_ptr<int> b = a;
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*a = 1;
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}
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void testInvalidated() {
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shared_ptr<int> a(new int);
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shared_ptr<int> b = a;
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*a = 1;
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extern void use(shared_ptr<int> &);
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use(b);
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}
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void testNestedScope() {
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shared_ptr<int> a(new int);
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{
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shared_ptr<int> b = a;
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}
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*a = 1;
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}
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void testSwap() {
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shared_ptr<int> a(new int);
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shared_ptr<int> b;
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shared_ptr<int> c = a;
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shared_ptr<int>(c).swap(b);
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}
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void testUseAfterFree() {
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int *p = new int;
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{
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shared_ptr<int> a(p);
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shared_ptr<int> b = a;
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}
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// FIXME: We should get a warning here, but we don't because we've
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// conservatively modeled ~shared_ptr.
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*p = 1;
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}
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}
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// Test double delete
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class DerefClass{
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public:
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int *x;
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DerefClass() {}
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~DerefClass() {
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int i = 0;
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x = &i;
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*x = 1;
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}
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};
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void testDoubleDeleteClassInstance() {
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DerefClass *foo = new DerefClass();
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delete foo;
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delete foo; // newdelete-warning {{Attempt to delete released memory}}
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}
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class EmptyClass{
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public:
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EmptyClass() {}
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~EmptyClass() {}
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};
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void testDoubleDeleteEmptyClass() {
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EmptyClass *foo = new EmptyClass();
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delete foo;
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delete foo; // newdelete-warning {{Attempt to delete released memory}}
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}
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struct Base {
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virtual ~Base() {}
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};
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struct Derived : Base {
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};
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Base *allocate() {
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return new Derived;
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}
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void shouldNotReportLeak() {
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Derived *p = (Derived *)allocate();
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delete p;
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}
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template<void *allocate_fn(size_t)>
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void* allocate_via_nttp(size_t n) {
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return allocate_fn(n);
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}
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template<void deallocate_fn(void*)>
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void deallocate_via_nttp(void* ptr) {
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deallocate_fn(ptr);
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}
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void testNTTPNewNTTPDelete() {
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void* p = allocate_via_nttp<::operator new>(10);
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deallocate_via_nttp<::operator delete>(p);
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} // no warn
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void testNTTPNewDirectDelete() {
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void* p = allocate_via_nttp<::operator new>(10);
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::operator delete(p);
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} // no warn
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void testDirectNewNTTPDelete() {
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void* p = ::operator new(10);
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deallocate_via_nttp<::operator delete>(p);
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}
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void not_free(void*) {
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}
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void testLeakBecauseNTTPIsNotDeallocation() {
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void* p = ::operator new(10);
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deallocate_via_nttp<not_free>(p);
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} // leak-warning{{Potential leak of memory pointed to by 'p'}}
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