r314975 - [analyzer] Fix leak false positives on stuff put in C++/ObjC initializer lists.
Artem Dergachev via cfe-commits
cfe-commits at lists.llvm.org
Thu Oct 5 01:43:33 PDT 2017
Author: dergachev
Date: Thu Oct 5 01:43:32 2017
New Revision: 314975
URL: http://llvm.org/viewvc/llvm-project?rev=314975&view=rev
Log:
[analyzer] Fix leak false positives on stuff put in C++/ObjC initializer lists.
The analyzer now realizes that C++ std::initializer_list objects and
Objective-C boxed structure/array/dictionary expressions can potentially
maintain a reference to the objects that were put into them. This avoids
false memory leak posivites and a few other issues.
This is a conservative behavior; for now, we do not model what actually happens
to the objects after being passed into such initializer lists.
rdar://problem/32918288
Differential Revision: https://reviews.llvm.org/D35216
Modified:
cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp
cfe/trunk/test/Analysis/initializer.cpp
cfe/trunk/test/Analysis/objc-boxing.m
cfe/trunk/test/Analysis/objc-for.m
Modified: cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp?rev=314975&r1=314974&r2=314975&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp Thu Oct 5 01:43:32 2017
@@ -827,6 +827,21 @@ void ExprEngine::VisitCXXBindTemporaryEx
}
}
+namespace {
+class CollectReachableSymbolsCallback final : public SymbolVisitor {
+ InvalidatedSymbols Symbols;
+
+public:
+ explicit CollectReachableSymbolsCallback(ProgramStateRef State) {}
+ const InvalidatedSymbols &getSymbols() const { return Symbols; }
+
+ bool VisitSymbol(SymbolRef Sym) override {
+ Symbols.insert(Sym);
+ return true;
+ }
+};
+} // end anonymous namespace
+
void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
ExplodedNodeSet &DstTop) {
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
@@ -1103,8 +1118,29 @@ void ExprEngine::Visit(const Stmt *S, Ex
SVal result = svalBuilder.conjureSymbolVal(nullptr, Ex, LCtx,
resultType,
currBldrCtx->blockCount());
- ProgramStateRef state = N->getState()->BindExpr(Ex, LCtx, result);
- Bldr2.generateNode(S, N, state);
+ ProgramStateRef State = N->getState()->BindExpr(Ex, LCtx, result);
+
+ // Escape pointers passed into the list, unless it's an ObjC boxed
+ // expression which is not a boxable C structure.
+ if (!(isa<ObjCBoxedExpr>(Ex) &&
+ !cast<ObjCBoxedExpr>(Ex)->getSubExpr()
+ ->getType()->isRecordType()))
+ for (auto Child : Ex->children()) {
+ assert(Child);
+
+ SVal Val = State->getSVal(Child, LCtx);
+
+ CollectReachableSymbolsCallback Scanner =
+ State->scanReachableSymbols<CollectReachableSymbolsCallback>(
+ Val);
+ const InvalidatedSymbols &EscapedSymbols = Scanner.getSymbols();
+
+ State = getCheckerManager().runCheckersForPointerEscape(
+ State, EscapedSymbols,
+ /*CallEvent*/ nullptr, PSK_EscapeOther, nullptr);
+ }
+
+ Bldr2.generateNode(S, N, State);
}
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, S, *this);
@@ -2237,21 +2273,6 @@ void ExprEngine::VisitAtomicExpr(const A
getCheckerManager().runCheckersForPostStmt(Dst, AfterInvalidateSet, AE, *this);
}
-namespace {
-class CollectReachableSymbolsCallback final : public SymbolVisitor {
- InvalidatedSymbols Symbols;
-
-public:
- CollectReachableSymbolsCallback(ProgramStateRef State) {}
- const InvalidatedSymbols &getSymbols() const { return Symbols; }
-
- bool VisitSymbol(SymbolRef Sym) override {
- Symbols.insert(Sym);
- return true;
- }
-};
-} // end anonymous namespace
-
// A value escapes in three possible cases:
// (1) We are binding to something that is not a memory region.
// (2) We are binding to a MemrRegion that does not have stack storage.
Modified: cfe/trunk/test/Analysis/initializer.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/initializer.cpp?rev=314975&r1=314974&r2=314975&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/initializer.cpp (original)
+++ cfe/trunk/test/Analysis/initializer.cpp Thu Oct 5 01:43:32 2017
@@ -1,7 +1,9 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc,debug.ExprInspection -analyzer-config c++-inlining=constructors -std=c++11 -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc,cplusplus.NewDeleteLeaks,debug.ExprInspection -analyzer-config c++-inlining=constructors -std=c++11 -verify %s
void clang_analyzer_eval(bool);
+#include "Inputs/system-header-simulator-cxx.h"
+
class A {
int x;
public:
@@ -204,3 +206,17 @@ struct C {
const char(&f)[2];
};
}
+
+namespace CXX_initializer_lists {
+struct C {
+ C(std::initializer_list<int *> list);
+};
+void foo() {
+ C empty{}; // no-crash
+
+ // Do not warn that 'x' leaks. It might have been deleted by
+ // the destructor of 'c'.
+ int *x = new int;
+ C c{x}; // no-warning
+}
+}
Modified: cfe/trunk/test/Analysis/objc-boxing.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/objc-boxing.m?rev=314975&r1=314974&r2=314975&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/objc-boxing.m (original)
+++ cfe/trunk/test/Analysis/objc-boxing.m Thu Oct 5 01:43:32 2017
@@ -5,6 +5,16 @@ void clang_analyzer_eval(int);
typedef signed char BOOL;
typedef long NSInteger;
typedef unsigned long NSUInteger;
+
+ at protocol NSObject
+ at end
+ at interface NSObject <NSObject> {}
+ at end
+ at protocol NSCopying
+ at end
+ at protocol NSCoding
+ at end
+
@interface NSString @end
@interface NSString (NSStringExtensionMethods)
+ (id)stringWithUTF8String:(const char *)nullTerminatedCString;
@@ -28,7 +38,15 @@ typedef unsigned long NSUInteger;
+ (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value ;
@end
+ at interface NSValue : NSObject <NSCopying, NSCoding>
+- (void)getValue:(void *)value;
++ (NSValue *)valueWithBytes:(const void *)value
+ objCType:(const char *)type;
+ at end
+typedef typeof(sizeof(int)) size_t;
+extern void *malloc(size_t);
+extern void free(void *);
extern char *strdup(const char *str);
id constant_string() {
@@ -39,6 +57,23 @@ id dynamic_string() {
return @(strdup("boxed dynamic string")); // expected-warning{{Potential memory leak}}
}
+typedef struct __attribute__((objc_boxable)) {
+ const char *str;
+} BoxableStruct;
+
+id leak_within_boxed_struct() {
+ BoxableStruct bs;
+ bs.str = strdup("dynamic string"); // The duped string shall be owned by val.
+ NSValue *val = @(bs); // no-warning
+ return val;
+}
+
+id leak_of_boxed_struct() {
+ BoxableStruct *bs = malloc(sizeof(BoxableStruct)); // The pointer stored in bs isn't owned by val.
+ NSValue *val = @(*bs); // expected-warning{{Potential leak of memory pointed to by 'bs'}}
+ return val;
+}
+
id const_char_pointer(int *x) {
if (x)
return @(3);
Modified: cfe/trunk/test/Analysis/objc-for.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/objc-for.m?rev=314975&r1=314974&r2=314975&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/objc-for.m (original)
+++ cfe/trunk/test/Analysis/objc-for.m Thu Oct 5 01:43:32 2017
@@ -1,6 +1,7 @@
// RUN: %clang_analyze_cc1 -analyzer-checker=core,osx.cocoa.Loops,debug.ExprInspection -verify %s
void clang_analyzer_eval(int);
+void clang_analyzer_warnIfReached();
#define nil ((id)0)
@@ -20,11 +21,13 @@ typedef unsigned long NSUInteger;
@interface NSArray : NSObject <NSFastEnumeration>
- (NSUInteger)count;
- (NSEnumerator *)objectEnumerator;
++ (NSArray *)arrayWithObjects:(const id [])objects count:(NSUInteger)count;
@end
@interface NSDictionary : NSObject <NSFastEnumeration>
- (NSUInteger)count;
- (id)objectForKey:(id)key;
++ (id)dictionaryWithObjects:(const id [])objects forKeys:(const id /* <NSCopying> */ [])keys count:(NSUInteger)count;
@end
@interface NSDictionary (SomeCategory)
@@ -324,3 +327,19 @@ void protocolMethods(NSMutableArray *arr
for (id key in array)
clang_analyzer_eval(0); // expected-warning{{FALSE}}
}
+
+NSArray *globalArray;
+NSDictionary *globalDictionary;
+void boxedArrayEscape(NSMutableArray *array) {
+ if ([array count])
+ return;
+ globalArray = @[array];
+ for (id key in array)
+ clang_analyzer_warnIfReached(); // expected-warning{{REACHABLE}}
+
+ if ([array count])
+ return;
+ globalDictionary = @{ @"array" : array };
+ for (id key in array)
+ clang_analyzer_warnIfReached(); // expected-warning{{REACHABLE}}
+}
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