NoQ created this revision.
NoQ added reviewers: rsmith, dcoughlin, xazax.hun, a.sidorin, george.karpenkov,
szepet.
Herald added subscribers: cfe-commits, rnkovacs.
This one's new, the analyzer didn't enjoy this before. This patch adds
construction context for `ReturnStmt`, which means that we'd be able to
properly return objects from functions by value.
This is the CFG part of the work, the Analyzer-side improvement to make use of
it will be in the next patch.
Repository:
rC Clang
https://reviews.llvm.org/D42875
Files:
lib/Analysis/CFG.cpp
test/Analysis/cfg-rich-constructors.cpp
test/Analysis/temp-obj-dtors-cfg-output.cpp
Index: test/Analysis/temp-obj-dtors-cfg-output.cpp
===================================================================
--- test/Analysis/temp-obj-dtors-cfg-output.cpp
+++ test/Analysis/temp-obj-dtors-cfg-output.cpp
@@ -220,7 +220,8 @@
// CHECK: 2: [B1.1] (BindTemporary)
// CHECK: 3: [B1.2] (ImplicitCastExpr, NoOp, const class A)
// CHECK: 4: [B1.3]
-// CHECK: 5: [B1.4] (CXXConstructExpr, class A)
+// WARNINGS: 5: [B1.4] (CXXConstructExpr, class A)
+// ANALYZER: 5: [B1.4] (CXXConstructExpr, [B1.7], class A)
// CHECK: 6: ~A() (Temporary object destructor)
// CHECK: 7: return [B1.5];
// CHECK: Preds (1): B2
@@ -278,7 +279,8 @@
// CHECK: 2: [B1.1] (BindTemporary)
// CHECK: 3: [B1.2] (ImplicitCastExpr, NoOp, const class A)
// CHECK: 4: [B1.3]
-// CHECK: 5: [B1.4] (CXXConstructExpr, class A)
+// WARNINGS: 5: [B1.4] (CXXConstructExpr, class A)
+// ANALYZER: 5: [B1.4] (CXXConstructExpr, [B1.7], class A)
// CHECK: 6: ~A() (Temporary object destructor)
// CHECK: 7: return [B1.5];
// CHECK: Preds (1): B2
Index: test/Analysis/cfg-rich-constructors.cpp
===================================================================
--- test/Analysis/cfg-rich-constructors.cpp
+++ test/Analysis/cfg-rich-constructors.cpp
@@ -5,6 +5,7 @@
public:
C();
C(C *);
+ C(int, int);
static C get();
};
@@ -224,3 +225,82 @@
};
} // end namespace ctor_initializers
+
+namespace return_stmt {
+
+// CHECK: C returnEmptyBraces()
+// CHECK: 1: {} (CXXConstructExpr, [B1.2], class C)
+// CHECK-NEXT: 2: return [B1.1];
+C returnEmptyBraces() {
+ return {};
+}
+
+// CHECK: C returnBracesWithOperatorNew()
+// CHECK: 1: CFGNewAllocator(C *)
+// CHECK-NEXT: 2: (CXXConstructExpr, [B1.3], class C)
+// CHECK-NEXT: 3: new C([B1.2])
+// CHECK-NEXT: 4: {[B1.3]} (CXXConstructExpr, [B1.5], class C)
+// CHECK-NEXT: 5: return [B1.4];
+C returnBracesWithOperatorNew() {
+ return {new C()};
+}
+
+// CHECK: C returnBracesWithMultipleItems()
+// CHECK: 1: 123
+// CHECK-NEXT: 2: 456
+// CHECK-NEXT: 3: {[B1.1], [B1.2]} (CXXConstructExpr, [B1.4], class C)
+// CHECK-NEXT: 4: return [B1.3];
+C returnBracesWithMultipleItems() {
+ return {123, 456};
+}
+
+// TODO: Should find construction targets for the first constructor as well.
+// CHECK: C returnTemporary()
+// CHECK: 1: C() (CXXConstructExpr, class C)
+// CHECK-NEXT: 2: [B1.1]
+// CHECK-NEXT: 3: [B1.2] (CXXConstructExpr, [B1.4], class C)
+// CHECK-NEXT: 4: return [B1.3];
+C returnTemporary() {
+ return C();
+}
+
+// TODO: Should find construction targets for the first constructor as well.
+// CHECK: C returnTemporaryWithArgument()
+// CHECK: 1: nullptr
+// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, NullToPointer, class C *)
+// CHECK-NEXT: 3: [B1.2] (CXXConstructExpr, class C)
+// CHECK-NEXT: 4: C([B1.3]) (CXXFunctionalCastExpr, ConstructorConversion, class C)
+// CHECK-NEXT: 5: [B1.4]
+// CHECK-NEXT: 6: [B1.5] (CXXConstructExpr, [B1.7], class C)
+// CHECK-NEXT: 7: return [B1.6];
+C returnTemporaryWithArgument() {
+ return C(nullptr);
+}
+
+// CHECK: C returnTemporaryConstructedByFunction()
+// CHECK: 1: C::get
+// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, class C (*)(void))
+// CHECK-NEXT: 3: [B1.2]()
+// CHECK-NEXT: 4: [B1.3]
+// CHECK-NEXT: 5: [B1.4] (CXXConstructExpr, [B1.6], class C)
+// CHECK-NEXT: 6: return [B1.5];
+C returnTemporaryConstructedByFunction() {
+ return C::get();
+}
+
+// TODO: Should find construction targets for the first constructor as well.
+// CHECK: C returnChainOfCopies()
+// CHECK: 1: C::get
+// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, class C (*)(void))
+// CHECK-NEXT: 3: [B1.2]()
+// CHECK-NEXT: 4: [B1.3]
+// CHECK-NEXT: 5: [B1.4] (CXXConstructExpr, class C)
+// CHECK-NEXT: 6: C([B1.5]) (CXXFunctionalCastExpr, ConstructorConversion, class C)
+// CHECK-NEXT: 7: [B1.6]
+// CHECK-NEXT: 8: [B1.7] (CXXConstructExpr, [B1.9], class C)
+// CHECK-NEXT: 9: return [B1.8];
+C returnChainOfCopies() {
+ return C(C::get());
+}
+
+} // end namespace return_stmt
Index: lib/Analysis/CFG.cpp
===================================================================
--- lib/Analysis/CFG.cpp
+++ lib/Analysis/CFG.cpp
@@ -2576,6 +2576,8 @@
addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
+ EnterConstructionContextIfNecessary(R, R->getRetValue());
+
// If the one of the destructors does not return, we already have the Exit
// block as a successor.
if (!Block->hasNoReturnElement())
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