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[CFG] [analyzer] Don't treat argument constructors as temporary constructors.

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Function argument constructors (that are used for passing objects into functions
by value) are completely unlike temporary object constructors, but we were
treating them as such because they are also wrapped into a CXXBindTemporaryExpr.

This patch adds a partial construction context layer for call argument values,
but doesn't proceed to transform it into an actual construction context yet.
This is tells the clients that we aren't supporting these constructors yet.

Differential Revision: https://reviews.llvm.org/D45650

llvm-svn: 330377
This commit is contained in:
Artem Dergachev 2018-04-19 23:09:22 +00:00
parent 1707fa3374
commit 72da02fc30
3 changed files with 85 additions and 0 deletions
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7
clang/lib/Analysis/CFG.cpp
View File

@ -2367,6 +2367,13 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
if (!boundType.isNull()) calleeType = boundType;
}
// FIXME: Once actually implemented, this construction context layer should
// include the number of the argument as well.
for (auto Arg: C->arguments()) {
findConstructionContexts(
ConstructionContextLayer::create(cfg->getBumpVectorContext(), C), Arg);
}
// If this is a call to a no-return function, this stops the block here.
bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();

6
clang/lib/Analysis/ConstructionContext.cpp
View File

@ -79,6 +79,9 @@ const ConstructionContext *ConstructionContext::createFromLayers(
ParentLayer->getTriggerStmt()))) {
return create<TemporaryObjectConstructionContext>(C, BTE, MTE);
}
// This is a constructor into a function argument. Not implemented yet.
if (auto *CE = dyn_cast<CallExpr>(ParentLayer->getTriggerStmt()))
return nullptr;
// This is C++17 copy-elided construction into return statement.
if (auto *RS = dyn_cast<ReturnStmt>(ParentLayer->getTriggerStmt())) {
assert(!RS->getRetValue()->getType().getCanonicalType()
@ -114,6 +117,9 @@ const ConstructionContext *ConstructionContext::createFromLayers(
assert(TopLayer->isLast());
return create<SimpleReturnedValueConstructionContext>(C, RS);
}
// This is a constructor into a function argument. Not implemented yet.
if (auto *CE = dyn_cast<CallExpr>(TopLayer->getTriggerStmt()))
return nullptr;
llvm_unreachable("Unexpected construction context with statement!");
} else if (const CXXCtorInitializer *I = TopLayer->getTriggerInit()) {
assert(TopLayer->isLast());

72
clang/test/Analysis/cfg-rich-constructors.cpp
View File

@ -693,3 +693,75 @@ void implicitConstructionConversionFromFunctionValueWithLifetimeExtension() {
}
} // end namespace implicit_constructor_conversion
namespace argument_constructors {
class D {
public:
D();
~D();
};
void useC(C c);
void useCByReference(const C &c);
void useD(D d);
void useDByReference(const D &d);
// FIXME: Find construction context for the argument.
// CHECK: void passArgument()
// CHECK: 1: useC
// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, void (*)(class C))
// CXX11-NEXT: 3: C() (CXXConstructExpr, [B1.4], class C)
// CXX11-NEXT: 4: [B1.3]
// CXX11-NEXT: 5: [B1.4] (CXXConstructExpr, class C)
// CXX11-NEXT: 6: [B1.2]([B1.5])
// CXX17-NEXT: 3: C() (CXXConstructExpr, class C)
// CXX17-NEXT: 4: [B1.2]([B1.3])
void passArgument() {
useC(C());
}
// CHECK: void passArgumentByReference()
// CHECK: 1: useCByReference
// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, void (*)(const class C &))
// CHECK-NEXT: 3: C() (CXXConstructExpr, [B1.5], class C)
// CHECK-NEXT: 4: [B1.3] (ImplicitCastExpr, NoOp, const class C)
// CHECK-NEXT: 5: [B1.4]
// CHECK-NEXT: 6: [B1.2]([B1.5])
void passArgumentByReference() {
useCByReference(C());
}
// FIXME: Find construction context for the argument.
// CHECK: void passArgumentWithDestructor()
// CHECK: 1: useD
// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, void (*)(class argument_constructors::D))
// CXX11-NEXT: 3: argument_constructors::D() (CXXConstructExpr, [B1.4], [B1.6], class argument_constructors::D)
// CXX11-NEXT: 4: [B1.3] (BindTemporary)
// CXX11-NEXT: 5: [B1.4] (ImplicitCastExpr, NoOp, const class argument_constructors::D)
// CXX11-NEXT: 6: [B1.5]
// CXX11-NEXT: 7: [B1.6] (CXXConstructExpr, class argument_constructors::D)
// CXX11-NEXT: 8: [B1.7] (BindTemporary)
// CXX11-NEXT: 9: [B1.2]([B1.8])
// CXX11-NEXT: 10: ~argument_constructors::D() (Temporary object destructor)
// CXX11-NEXT: 11: ~argument_constructors::D() (Temporary object destructor)
// CXX17-NEXT: 3: argument_constructors::D() (CXXConstructExpr, class argument_constructors::D)
// CXX17-NEXT: 4: [B1.3] (BindTemporary)
// CXX17-NEXT: 5: [B1.2]([B1.4])
// CXX17-NEXT: 6: ~argument_constructors::D() (Temporary object destructor)
void passArgumentWithDestructor() {
useD(D());
}
// CHECK: void passArgumentWithDestructorByReference()
// CHECK: 1: useDByReference
// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, void (*)(const class argumen
// CHECK-NEXT: 3: argument_constructors::D() (CXXConstructExpr, [B1.4], [B1.6], class argument_c
// CHECK-NEXT: 4: [B1.3] (BindTemporary)
// CHECK-NEXT: 5: [B1.4] (ImplicitCastExpr, NoOp, const class argument_constructors::D)
// CHECK-NEXT: 6: [B1.5]
// CHECK-NEXT: 7: [B1.2]([B1.6])
// CHECK-NEXT: 8: ~argument_constructors::D() (Temporary object destructor)
void passArgumentWithDestructorByReference() {
useDByReference(D());
}
} // end namespace argument_constructors