r293043 - [analyzer] Fix MacOSXAPIChecker fp with static locals seen from nested blocks.
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Wed Feb 1 11:00:09 PST 2017
If Anna is Ok with it, I'm fine with merging.
Thanks,
Hans
On Wed, Feb 1, 2017 at 10:29 AM, Artem Dergachev <noqnoqneo at gmail.com> wrote:
> Hans,
>
> This is a fixed and tested version of the previously-merged-and-reverted
> r292800, do we still have time to land this into 4.0?
>
> Thanks,
> Artem.
>
>
> On 1/25/17 1:21 PM, Artem Dergachev via cfe-commits wrote:
>>
>> Author: dergachev
>> Date: Wed Jan 25 04:21:45 2017
>> New Revision: 293043
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=293043&view=rev
>> Log:
>> [analyzer] Fix MacOSXAPIChecker fp with static locals seen from nested
>> blocks.
>>
>> This is an attempt to avoid new false positives caused by the reverted
>> r292800,
>> however the scope of the fix is significantly reduced - some variables are
>> still
>> in incorrect memory spaces.
>>
>> Relevant test cases added.
>>
>> rdar://problem/30105546
>> rdar://problem/30156693
>> Differential revision: https://reviews.llvm.org/D28946
>>
>> Added:
>> cfe/trunk/test/Analysis/null-deref-static.m
>> Modified:
>> cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
>> cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
>> cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
>> cfe/trunk/test/Analysis/dispatch-once.m
>>
>> Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp?rev=293043&r1=293042&r2=293043&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp (original)
>> +++ cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp Wed Jan 25
>> 04:21:45 2017
>> @@ -94,11 +94,18 @@ void MacOSXAPIChecker::CheckDispatchOnce
>> bool SuggestStatic = false;
>> os << "Call to '" << FName << "' uses";
>> if (const VarRegion *VR = dyn_cast<VarRegion>(RB)) {
>> + const VarDecl *VD = VR->getDecl();
>> + // FIXME: These should have correct memory space and thus should be
>> filtered
>> + // out earlier. This branch only fires when we're looking from a
>> block,
>> + // which we analyze as a top-level declaration, onto a static local
>> + // in a function that contains the block.
>> + if (VD->isStaticLocal())
>> + return;
>> // We filtered out globals earlier, so it must be a local variable
>> // or a block variable which is under UnknownSpaceRegion.
>> if (VR != R)
>> os << " memory within";
>> - if (VR->getDecl()->hasAttr<BlocksAttr>())
>> + if (VD->hasAttr<BlocksAttr>())
>> os << " the block variable '";
>> else
>> os << " the local variable '";
>>
>> Modified: cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp?rev=293043&r1=293042&r2=293043&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp (original)
>> +++ cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp Wed Jan 25 04:21:45
>> 2017
>> @@ -816,9 +816,11 @@ const VarRegion* MemRegionManager::getVa
>> const StackFrameContext *STC = V.get<const StackFrameContext*>();
>> - if (!STC)
>> + if (!STC) {
>> + // FIXME: Assign a more sensible memory space to static locals
>> + // we see from within blocks that we analyze as top-level
>> declarations.
>> sReg = getUnknownRegion();
>> - else {
>> + } else {
>> if (D->hasLocalStorage()) {
>> sReg = isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)
>> ? static_cast<const
>> MemRegion*>(getStackArgumentsRegion(STC))
>>
>> Modified: cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp?rev=293043&r1=293042&r2=293043&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp (original)
>> +++ cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp Wed Jan 25 04:21:45
>> 2017
>> @@ -1849,6 +1849,8 @@ SVal RegionStoreManager::getBindingForVa
>> // Function-scoped static variables are default-initialized to 0;
>> if they
>> // have an initializer, it would have been processed by now.
>> + // FIXME: This is only true when we're starting analysis from main().
>> + // We're losing a lot of coverage here.
>> if (isa<StaticGlobalSpaceRegion>(MS))
>> return svalBuilder.makeZeroVal(T);
>>
>> Modified: cfe/trunk/test/Analysis/dispatch-once.m
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/dispatch-once.m?rev=293043&r1=293042&r2=293043&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/Analysis/dispatch-once.m (original)
>> +++ cfe/trunk/test/Analysis/dispatch-once.m Wed Jan 25 04:21:45 2017
>> @@ -107,3 +107,10 @@ void test_block_var_from_outside_block()
>> };
>> dispatch_once(&once, ^{}); // expected-warning{{Call to
>> 'dispatch_once' uses the block variable 'once' for the predicate value.}}
>> }
>> +
>> +void test_static_var_from_outside_block() {
>> + static dispatch_once_t once;
>> + ^{
>> + dispatch_once(&once, ^{}); // no-warning
>> + };
>> +}
>>
>> Added: cfe/trunk/test/Analysis/null-deref-static.m
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/null-deref-static.m?rev=293043&view=auto
>>
>> ==============================================================================
>> --- cfe/trunk/test/Analysis/null-deref-static.m (added)
>> +++ cfe/trunk/test/Analysis/null-deref-static.m Wed Jan 25 04:21:45 2017
>> @@ -0,0 +1,35 @@
>> +// RUN: %clang_cc1 -w -fblocks -analyze
>> -analyzer-checker=core,deadcode,alpha.core,debug.ExprInspection -verify %s
>> +
>> +void *malloc(unsigned long);
>> +void clang_analyzer_warnIfReached();
>> +
>> +void test_static_from_block() {
>> + static int *x;
>> + ^{
>> + *x; // no-warning
>> + };
>> +}
>> +
>> +void test_static_within_block() {
>> + ^{
>> + static int *x;
>> + *x; // expected-warning{{Dereference of null pointer}}
>> + };
>> +}
>> +
>> +void test_static_control_flow(int y) {
>> + static int *x;
>> + if (x) {
>> + // FIXME: Should be reachable.
>> + clang_analyzer_warnIfReached(); // no-warning
>> + }
>> + if (y) {
>> + // We are not sure if this branch is possible, because the developer
>> + // may argue that function is always called with y == 1 for the first
>> time.
>> + // In this case, we can only advise the developer to add assertions
>> + // for suppressing such path.
>> + *x; // expected-warning{{Dereference of null pointer}}
>> + } else {
>> + x = malloc(1);
>> + }
>> +}
>>
>>
>> _______________________________________________
>> cfe-commits mailing list
>> cfe-commits at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>
>
More information about the cfe-commits
mailing list