Author: hans
Date: Mon Aug 21 13:27:26 2017
New Revision: 311378
URL: http://llvm.org/viewvc/llvm-project?rev=311378&view=rev
Log:
Merging r311182:
------------------------------------------------------------------------
r311182 | alexshap | 2017-08-18 11:20:43 -0700 (Fri, 18 Aug 2017) | 22 lines
[analyzer] Fix modeling of constructors
This diff fixes analyzer's crash (triggered assert) on the newly added test
case.
The assert being discussed is assert(!B.lookup(R, BindingKey::Direct))
in lib/StaticAnalyzer/Core/RegionStore.cpp, however the root cause is different.
For classes with empty bases the offsets might be tricky.
For example, let's assume we have
struct S: NonEmptyBase, EmptyBase {
...
};
In this case Clang applies empty base class optimization and
the offset of EmptyBase will be 0, it can be verified via
clang -cc1 -x c++ -v -fdump-record-layouts main.cpp -emit-llvm -o /dev/null.
When the analyzer tries to perform zero initialization of EmptyBase
it will hit the assert because that region
has already been "written" by the constructor of NonEmptyBase.
Test plan:
make check-all
Differential revision: https://reviews.llvm.org/D36851
------------------------------------------------------------------------
Modified:
cfe/branches/release_50/ (props changed)
cfe/branches/release_50/lib/StaticAnalyzer/Core/RegionStore.cpp
cfe/branches/release_50/test/Analysis/ctor.mm
Propchange: cfe/branches/release_50/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon Aug 21 13:27:26 2017
@@ -1,4 +1,4 @@
/cfe/branches/type-system-rewrite:134693-134817
-/cfe/trunk:308455,308722,308824,308897,308996,309054,309058,309112-309113,309226,309263,309327,309382-309383,309488,309503,309523,309569,309607,309633,309636,309640,309722,309752,309975,310006,310158,310191,310359,310516,310672,310691-310692,310694,310700,310704,310706,310776,310804,310829,311115
+/cfe/trunk:308455,308722,308824,308897,308996,309054,309058,309112-309113,309226,309263,309327,309382-309383,309488,309503,309523,309569,309607,309633,309636,309640,309722,309752,309975,310006,310158,310191,310359,310516,310672,310691-310692,310694,310700,310704,310706,310776,310804,310829,311115,311182
/cfe/trunk/test:170344
/cfe/trunk/test/SemaTemplate:126920
Modified: cfe/branches/release_50/lib/StaticAnalyzer/Core/RegionStore.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/branches/release_50/lib/StaticAnalyzer/Core/RegionStore.cpp?rev=311378&r1=311377&r2=311378&view=diff
==============================================================================
--- cfe/branches/release_50/lib/StaticAnalyzer/Core/RegionStore.cpp (original)
+++ cfe/branches/release_50/lib/StaticAnalyzer/Core/RegionStore.cpp Mon Aug 21
13:27:26 2017
@@ -409,6 +409,19 @@ public: // Part of public interface to c
// BindDefault is only used to initialize a region with a default value.
StoreRef BindDefault(Store store, const MemRegion *R, SVal V) override {
+ // FIXME: The offsets of empty bases can be tricky because of
+ // of the so called "empty base class optimization".
+ // If a base class has been optimized out
+ // we should not try to create a binding, otherwise we should.
+ // Unfortunately, at the moment ASTRecordLayout doesn't expose
+ // the actual sizes of the empty bases
+ // and trying to infer them from offsets/alignments
+ // seems to be error-prone and non-trivial because of the trailing padding.
+ // As a temporary mitigation we don't create bindings for empty bases.
+ if (R->getKind() == MemRegion::CXXBaseObjectRegionKind &&
+ cast<CXXBaseObjectRegion>(R)->getDecl()->isEmpty())
+ return StoreRef(store, *this);
+
RegionBindingsRef B = getRegionBindings(store);
assert(!B.lookup(R, BindingKey::Direct));
Modified: cfe/branches/release_50/test/Analysis/ctor.mm
URL:
http://llvm.org/viewvc/llvm-project/cfe/branches/release_50/test/Analysis/ctor.mm?rev=311378&r1=311377&r2=311378&view=diff
==============================================================================
--- cfe/branches/release_50/test/Analysis/ctor.mm (original)
+++ cfe/branches/release_50/test/Analysis/ctor.mm Mon Aug 21 13:27:26 2017
@@ -704,3 +704,20 @@ namespace PR19579 {
};
}
}
+
+namespace NoCrashOnEmptyBaseOptimization {
+ struct NonEmptyBase {
+ int X;
+ explicit NonEmptyBase(int X) : X(X) {}
+ };
+
+ struct EmptyBase {};
+
+ struct S : NonEmptyBase, EmptyBase {
+ S() : NonEmptyBase(0), EmptyBase() {}
+ };
+
+ void testSCtorNoCrash() {
+ S s;
+ }
+}
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