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[analyzer] Malloc checker: mark 'strdup' and 'strndup' as allocators. 

llvm-svn: 151124
This commit is contained in:
Anna Zaks 2012-02-22 03:14:20 +00:00
parent e67173e718
commit 199e8e585b
2 changed files with 60 additions and 19 deletions
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60
clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
View File

@ -26,6 +26,8 @@
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/STLExtras.h"
#include <climits>
using namespace clang;
using namespace ento;
@ -97,11 +99,13 @@ class MallocChecker : public Checker<check::DeadSymbols,
mutable OwningPtr<BugType> BT_UseFree;
mutable OwningPtr<BugType> BT_BadFree;
mutable IdentifierInfo *II_malloc, *II_free, *II_realloc, *II_calloc,
*II_valloc, *II_reallocf;
*II_valloc, *II_reallocf, *II_strndup, *II_strdup;
static const unsigned InvalidArgIndex = UINT_MAX;
public:
MallocChecker() : II_malloc(0), II_free(0), II_realloc(0), II_calloc(0),
II_valloc(0), II_reallocf(0) {}
II_valloc(0), II_reallocf(0), II_strndup(0), II_strdup(0) {}
/// In pessimistic mode, the checker assumes that it does not know which
/// functions might free the memory.
@ -140,7 +144,8 @@ private:
/// pointed to by one of its arguments.
bool isMemFunction(const FunctionDecl *FD, ASTContext &C) const;
static void MallocMem(CheckerContext &C, const CallExpr *CE);
static void MallocMem(CheckerContext &C, const CallExpr *CE,
unsigned SizeIdx);
static void MallocMemReturnsAttr(CheckerContext &C, const CallExpr *CE,
const OwnershipAttr* Att);
static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE,
@ -283,6 +288,10 @@ void MallocChecker::initIdentifierInfo(ASTContext &Ctx) const {
II_calloc = &Ctx.Idents.get("calloc");
if (!II_valloc)
II_valloc = &Ctx.Idents.get("valloc");
if (!II_strdup)
II_strdup = &Ctx.Idents.get("strdup");
if (!II_strndup)
II_strndup = &Ctx.Idents.get("strndup");
}
bool MallocChecker::isMemFunction(const FunctionDecl *FD, ASTContext &C) const {
@ -294,9 +303,9 @@ bool MallocChecker::isMemFunction(const FunctionDecl *FD, ASTContext &C) const {
initIdentifierInfo(C);
// TODO: Add more here : ex: reallocf!
if (FunI == II_malloc || FunI == II_free || FunI == II_realloc ||
FunI == II_reallocf || FunI == II_calloc || FunI == II_valloc)
FunI == II_reallocf || FunI == II_calloc || FunI == II_valloc ||
FunI == II_strdup || FunI == II_strndup)
return true;
if (Filter.CMallocOptimistic && FD->hasAttrs() &&
@ -319,7 +328,7 @@ void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const {
return;
if (FunI == II_malloc || FunI == II_valloc) {
MallocMem(C, CE);
MallocMem(C, CE, 0);
return;
} else if (FunI == II_realloc) {
ReallocMem(C, CE, false);
@ -330,9 +339,15 @@ void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const {
} else if (FunI == II_calloc) {
CallocMem(C, CE);
return;
}else if (FunI == II_free) {
} else if (FunI == II_free) {
FreeMem(C, CE);
return;
} else if (FunI == II_strdup) {
MallocMem(C, CE, InvalidArgIndex);
return;
} else if (FunI == II_strndup) {
MallocMem(C, CE, 1);
return;
}
if (Filter.CMallocOptimistic)
@ -358,10 +373,16 @@ void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const {
}
}
void MallocChecker::MallocMem(CheckerContext &C, const CallExpr *CE) {
ProgramStateRef state = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(),
C.getState());
C.addTransition(state);
void MallocChecker::MallocMem(CheckerContext &C, const CallExpr *CE,
unsigned SizeIdx) {
SVal Undef = UndefinedVal();
ProgramStateRef State;
if (SizeIdx != InvalidArgIndex)
State = MallocMemAux(C, CE, CE->getArg(SizeIdx), Undef, C.getState());
else
State = MallocMemAux(C, CE, Undef, Undef, C.getState());
C.addTransition(State);
}
void MallocChecker::MallocMemReturnsAttr(CheckerContext &C, const CallExpr *CE,
@ -400,16 +421,17 @@ ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C,
// Set the region's extent equal to the Size parameter.
const SymbolicRegion *R =
dyn_cast_or_null<SymbolicRegion>(retVal.getAsRegion());
if (!R || !isa<DefinedOrUnknownSVal>(Size))
if (!R)
return 0;
if (isa<DefinedOrUnknownSVal>(Size)) {
DefinedOrUnknownSVal Extent = R->getExtent(svalBuilder);
DefinedOrUnknownSVal DefinedSize = cast<DefinedOrUnknownSVal>(Size);
DefinedOrUnknownSVal extentMatchesSize =
svalBuilder.evalEQ(state, Extent, DefinedSize);
DefinedOrUnknownSVal Extent = R->getExtent(svalBuilder);
DefinedOrUnknownSVal DefinedSize = cast<DefinedOrUnknownSVal>(Size);
DefinedOrUnknownSVal extentMatchesSize =
svalBuilder.evalEQ(state, Extent, DefinedSize);
state = state->assume(extentMatchesSize, true);
assert(state);
state = state->assume(extentMatchesSize, true);
assert(state);
}
SymbolRef Sym = retVal.getAsLocSymbol();
assert(Sym);

19
clang/test/Analysis/malloc.c
View File

@ -652,6 +652,25 @@ int *specialMallocWithStruct() {
return &(px->g);
}
// Test various allocation/deallocation functions.
char *strdup(const char *s);
char *strndup(const char *s, size_t n);
void testStrdup(const char *s, unsigned validIndex) {
char *s2 = strdup(s);
s2[validIndex + 1] = 'b';// expected-warning {{Memory is never released; potential memory leak}}
}
int testStrndup(const char *s, unsigned validIndex, unsigned size) {
char *s2 = strndup(s, size);
s2 [validIndex + 1] = 'b';
if (s2[validIndex] != 'a')
return 0;// expected-warning {{Memory is never released; potential memory leak}}
else
return 1;// expected-warning {{Memory is never released; potential memory leak}}
}
// Below are the known false positives.
// TODO: There should be no warning here. This one might be difficult to get rid of.