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[analyzer] Model lifetime of a variable declared in for condition in CFG correctly

Browse Source 
Per [stmt.for] p1 (https://eel.is/c++draft/stmt.for#1) the following
`for` and `while` statements are equivalent
```
for (; A c = b; b.c) {
  A d;
}

while (A c = b) {
  A d;
  b.c;
}
```
As a consequence, the variable declared for the condition expression
should be destroyed after the increment expression.

This fixed the handling of the object lifetime `continue`, and now
destructors, scope and lifetime elements are present for continue
path in following code:
```
for (; A c = b; b.c) {
  if (cond)
     continue;
  A d;
}
```

Reviewed By: xazax.hun

Differential Revision: https://reviews.llvm.org/D155547
This commit is contained in:
tomasz-kaminski-sonarsource 2023-07-18 16:55:50 +02:00 committed by Tomasz Kamiński
parent faf77f8dec
commit c3dd2f35b8
4 changed files with 215 additions and 18 deletions
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7
clang/lib/Analysis/CFG.cpp
View File

@ -3511,6 +3511,11 @@ CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
Block = Succ = TransitionBlock = createBlock(false);
TransitionBlock->setLoopTarget(F);
// Loop iteration (after increment) should end with destructor of Condition
// variable (if any).
addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
if (Stmt *I = F->getInc()) {
// Generate increment code in its own basic block. This is the target of
// continue statements.
@ -3530,8 +3535,6 @@ CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
ContinueJumpTarget.block->setLoopTarget(F);
// Loop body should end with destructor of Condition variable (if any).
addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
// If body is not a compound statement create implicit scope
// and add destructors.

74
clang/test/Analysis/auto-obj-dtors-cfg-output.cpp
View File

@ -1040,6 +1040,10 @@ void test_switch_jumps() {
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B2.1].x
// CHECK-NEXT: 3: ++[B2.2]
// CHECK-NEXT: 4: [B4.4].~A() (Implicit destructor)
// CHECK-NEXT: Preds (1): B3
// CHECK-NEXT: Succs (1): B4
// CHECK: [B3]
@ -1047,7 +1051,6 @@ void test_switch_jumps() {
// ANALYZER-NEXT: 1: (CXXConstructExpr, [B3.2], A)
// CHECK-NEXT: 2: A c;
// CHECK-NEXT: 3: [B3.2].~A() (Implicit destructor)
// CHECK-NEXT: 4: [B4.4].~A() (Implicit destructor)
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -1062,7 +1065,7 @@ void test_switch_jumps() {
// CHECK-NEXT: 8: [B4.6]
// CHECK-NEXT: 9: [B4.8] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK: 10: [B4.9] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B4.10]; )
// CHECK-NEXT: T: for (...; [B4.10]; ...)
// CHECK-NEXT: Preds (2): B2 B5
// CHECK-NEXT: Succs (2): B3 B1
// CHECK: [B5]
@ -1074,7 +1077,7 @@ void test_switch_jumps() {
// CHECK: [B0 (EXIT)]
// CHECK-NEXT: Preds (1): B1
void test_for_implicit_scope() {
for (A a; A b = a; )
for (A a; A b = a; ++b.x)
A c;
}
@ -1144,6 +1147,7 @@ void test_for_range_implicit_scope() {
// CHECK-NEXT: Preds (2): B8 B10
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B10.4].~A() (Implicit destructor)
// CHECK-NEXT: Preds (2): B3 B6
// CHECK-NEXT: Succs (1): B10
// CHECK: [B3]
@ -1152,7 +1156,6 @@ void test_for_range_implicit_scope() {
// CHECK-NEXT: 2: A e;
// CHECK-NEXT: 3: [B3.2].~A() (Implicit destructor)
// CHECK-NEXT: 4: [B9.2].~A() (Implicit destructor)
// CHECK-NEXT: 5: [B10.4].~A() (Implicit destructor)
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -1222,7 +1225,7 @@ void test_for_range_implicit_scope() {
// CHECK-NEXT: Preds (2): B1 B4
void test_for_jumps() {
A a;
for (A b; A c = b; ) {
for (A b; A c = b;) {
A d;
if (UV) break;
if (UV) continue;
@ -1232,6 +1235,67 @@ void test_for_jumps() {
A f;
}
// CHECK: [B9 (ENTRY)]
// CHECK-NEXT: Succs (1): B8
// CHECK: [B1]
// CHECK-NEXT: 1: [B7.4].~A() (Implicit destructor)
// CHECK-NEXT: 2: [B8.2].~A() (Implicit destructor)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B5.4] ? [B3.3] : [B4.1]
// CHECK-NEXT: 2: [B7.4].~A() (Implicit destructor)
// CHECK-NEXT: Preds (2): B3 B4
// CHECK-NEXT: Succs (1): B7
// CHECK: [B3]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B3.1].x
// CHECK-NEXT: 3: [B3.2]++
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B5]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B5.1].x
// CHECK-NEXT: 3: [B5.2] (ImplicitCastExpr, LValueToRValue, int)
// CHECK-NEXT: 4: [B5.3] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: [B5.4] ? ... : ...
// CHECK-NEXT: Preds (1): B6
// CHECK-NEXT: Succs (2): B3 B4
// CHECK: [B6]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: 2: (void)[B6.1] (CStyleCastExpr, ToVoid, void)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B5
// CHECK: [B7]
// CHECK-NEXT: 1: a
// CHECK-NEXT: 2: [B7.1] (ImplicitCastExpr, NoOp, const A)
// WARNINGS-NEXT: 3: [B7.2] (CXXConstructExpr, A)
// ANALYZER-NEXT: 3: [B7.2] (CXXConstructExpr, [B7.4], A)
// CHECK-NEXT: 4: A b = a;
// CHECK-NEXT: 5: b
// CHECK-NEXT: 6: [B7.5] (ImplicitCastExpr, NoOp, const class A)
// CHECK-NEXT: 7: [B7.6].operator int
// CHECK-NEXT: 8: [B7.6]
// CHECK-NEXT: 9: [B7.8] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK-NEXT: 10: [B7.9] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B7.10]; ...)
// CHECK-NEXT: Preds (2): B2 B8
// CHECK-NEXT: Succs (2): B6 B1
// CHECK: [B8]
// WARNINGS-NEXT: 1: (CXXConstructExpr, A)
// ANALYZER-NEXT: 1: (CXXConstructExpr, [B8.2], A)
// CHECK-NEXT: 2: A a;
// CHECK-NEXT: Preds (1): B9
// CHECK-NEXT: Succs (1): B7
void test_for_inc_conditional() {
for (A a; A b = a; b.x ? b.x++ : 0)
(void)0;
}
// CHECK: [B3 (ENTRY)]
// CHECK-NEXT: Succs (1): B0
// CHECK: [B1]

72
clang/test/Analysis/lifetime-cfg-output.cpp
View File

@ -529,13 +529,15 @@ void test_do_jumps() {
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B2.1].p
// CHECK-NEXT: 3: [B4.4] (Lifetime ends)
// CHECK-NEXT: Preds (1): B3
// CHECK-NEXT: Succs (1): B4
// CHECK: [B3]
// CHECK-NEXT: 1: (CXXConstructExpr, A)
// CHECK-NEXT: 2: A c;
// CHECK-NEXT: 3: [B3.2] (Lifetime ends)
// CHECK-NEXT: 4: [B4.4] (Lifetime ends)
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -549,7 +551,7 @@ void test_do_jumps() {
// CHECK-NEXT: 8: [B4.6]
// CHECK-NEXT: 9: [B4.8] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK-NEXT: 10: [B4.9] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B4.10]; )
// CHECK-NEXT: T: for (...; [B4.10]; ...)
// CHECK-NEXT: Preds (2): B2 B5
// CHECK-NEXT: Succs (2): B3 B1
// CHECK: [B5]
@ -560,7 +562,7 @@ void test_do_jumps() {
// CHECK: [B0 (EXIT)]
// CHECK-NEXT: Preds (1): B1
void test_for_implicit_scope() {
for (A a; A b = a;)
for (A a; A b = a; b.p)
A c;
}
@ -576,6 +578,7 @@ void test_for_implicit_scope() {
// CHECK-NEXT: Preds (2): B8 B10
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B10.4] (Lifetime ends)
// CHECK-NEXT: Preds (2): B3 B6
// CHECK-NEXT: Succs (1): B10
// CHECK: [B3]
@ -583,7 +586,6 @@ void test_for_implicit_scope() {
// CHECK-NEXT: 2: A e;
// CHECK-NEXT: 3: [B3.2] (Lifetime ends)
// CHECK-NEXT: 4: [B9.2] (Lifetime ends)
// CHECK-NEXT: 5: [B10.4] (Lifetime ends)
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -649,7 +651,7 @@ void test_for_implicit_scope() {
// CHECK-NEXT: Preds (2): B1 B4
void test_for_jumps() {
A a;
for (A b; A c = b;) {
for (A b; A c = b; ) {
A d;
if (UV)
break;
@ -662,6 +664,66 @@ void test_for_jumps() {
A f;
}
// CHECK: [B9 (ENTRY)]
// CHECK-NEXT: Succs (1): B8
// CHECK: [B1]
// CHECK-NEXT: 1: [B7.4] (Lifetime ends)
// CHECK-NEXT: 2: [B8.2] (Lifetime ends)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B5.4] ? [B3.3] : [B4.2]
// CHECK-NEXT: 2: [B7.4] (Lifetime ends)
// CHECK-NEXT: Preds (2): B3 B4
// CHECK-NEXT: Succs (1): B7
// CHECK: [B3]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B3.1].p
// CHECK-NEXT: 3: [B3.2]++
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: 2: [B4.1] (ImplicitCastExpr, NullToPointer, int *)
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B5]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B5.1].p
// CHECK-NEXT: 3: [B5.2] (ImplicitCastExpr, LValueToRValue, int *)
// CHECK-NEXT: 4: [B5.3] (ImplicitCastExpr, PointerToBoolean, _Bool)
// CHECK-NEXT: T: [B5.4] ? ... : ...
// CHECK-NEXT: Preds (1): B6
// CHECK-NEXT: Succs (2): B3 B4
// CHECK: [B6]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: 2: (void)[B6.1] (CStyleCastExpr, ToVoid, void)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B5
// CHECK: [B7]
// CHECK-NEXT: 1: a
// CHECK-NEXT: 2: [B7.1] (ImplicitCastExpr, NoOp, const A)
// CHECK-NEXT: 3: [B7.2] (CXXConstructExpr, A)
// CHECK-NEXT: 4: A b = a;
// CHECK-NEXT: 5: b
// CHECK-NEXT: 6: [B7.5] (ImplicitCastExpr, NoOp, const class A)
// CHECK-NEXT: 7: [B7.6].operator int
// CHECK-NEXT: 8: [B7.6]
// CHECK-NEXT: 9: [B7.8] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK-NEXT: 10: [B7.9] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B7.10]; ...)
// CHECK-NEXT: Preds (2): B2 B8
// CHECK-NEXT: Succs (2): B6 B1
// CHECK: [B8]
// CHECK-NEXT: 1: (CXXConstructExpr, A)
// CHECK-NEXT: 2: A a;
// CHECK-NEXT: Preds (1): B9
// CHECK-NEXT: Succs (1): B7
void test_for_inc_conditional() {
for (A a; A b = a; b.p ? b.p++ : 0)
(void)0;
}
// CHECK: [B2 (ENTRY)]
// CHECK-NEXT: Succs (1): B1
// CHECK: [B1]

80
clang/test/Analysis/scopes-cfg-output.cpp
View File

@ -25,6 +25,7 @@ public:
// CHECK: [B0 (EXIT)]
// CHECK-NEXT: Preds (1): B1
operator int() const { return 1; }
int *p;
};
int getX();
@ -524,6 +525,10 @@ void test_do_jumps() {
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B2.1].p
// CHECK-NEXT: 3: [B4.5].~A() (Implicit destructor)
// CHECK-NEXT: 4: CFGScopeEnd(b)
// CHECK-NEXT: Preds (1): B3
// CHECK-NEXT: Succs (1): B4
// CHECK: [B3]
@ -532,8 +537,6 @@ void test_do_jumps() {
// CHECK-NEXT: 3: A c;
// CHECK-NEXT: 4: [B3.3].~A() (Implicit destructor)
// CHECK-NEXT: 5: CFGScopeEnd(c)
// CHECK-NEXT: 6: [B4.5].~A() (Implicit destructor)
// CHECK-NEXT: 7: CFGScopeEnd(b)
// CHECK-NEXT: Preds (1): B4
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -548,7 +551,7 @@ void test_do_jumps() {
// CHECK-NEXT: 9: [B4.7]
// CHECK-NEXT: 10: [B4.9] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK-NEXT: 11: [B4.10] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B4.11]; )
// CHECK-NEXT: T: for (...; [B4.11]; ...)
// CHECK-NEXT: Preds (2): B2 B5
// CHECK-NEXT: Succs (2): B3 B1
// CHECK: [B5]
@ -560,7 +563,7 @@ void test_do_jumps() {
// CHECK: [B0 (EXIT)]
// CHECK-NEXT: Preds (1): B1
void test_for_implicit_scope() {
for (A a; A b = a; )
for (A a; A b = a; b.p)
A c;
}
@ -579,6 +582,8 @@ void test_for_implicit_scope() {
// CHECK-NEXT: Preds (2): B8 B10
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B10.5].~A() (Implicit destructor)
// CHECK-NEXT: 2: CFGScopeEnd(c)
// CHECK-NEXT: Preds (2): B3 B6
// CHECK-NEXT: Succs (1): B10
// CHECK: [B3]
@ -587,8 +592,6 @@ void test_for_implicit_scope() {
// CHECK-NEXT: 3: [B3.2].~A() (Implicit destructor)
// CHECK-NEXT: 4: [B9.3].~A() (Implicit destructor)
// CHECK-NEXT: 5: CFGScopeEnd(d)
// CHECK-NEXT: 6: [B10.5].~A() (Implicit destructor)
// CHECK-NEXT: 7: CFGScopeEnd(c)
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
@ -674,6 +677,71 @@ void test_for_jumps() {
A f;
}
// CHECK: [B9 (ENTRY)]
// CHECK-NEXT: Succs (1): B8
// CHECK: [B1]
// CHECK-NEXT: 1: [B7.5].~A() (Implicit destructor)
// CHECK-NEXT: 2: CFGScopeEnd(b)
// CHECK-NEXT: 3: [B8.3].~A() (Implicit destructor)
// CHECK-NEXT: 4: CFGScopeEnd(a)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B0
// CHECK: [B2]
// CHECK-NEXT: 1: [B5.4] ? [B3.3] : [B4.2]
// CHECK-NEXT: 2: [B7.5].~A() (Implicit destructor)
// CHECK-NEXT: 3: CFGScopeEnd(b)
// CHECK-NEXT: Preds (2): B3 B4
// CHECK-NEXT: Succs (1): B7
// CHECK: [B3]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B3.1].p
// CHECK-NEXT: 3: [B3.2]++
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B4]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: 2: [B4.1] (ImplicitCastExpr, NullToPointer, int *)
// CHECK-NEXT: Preds (1): B5
// CHECK-NEXT: Succs (1): B2
// CHECK: [B5]
// CHECK-NEXT: 1: b
// CHECK-NEXT: 2: [B5.1].p
// CHECK-NEXT: 3: [B5.2] (ImplicitCastExpr, LValueToRValue, int *)
// CHECK-NEXT: 4: [B5.3] (ImplicitCastExpr, PointerToBoolean, _Bool)
// CHECK-NEXT: T: [B5.4] ? ... : ...
// CHECK-NEXT: Preds (1): B6
// CHECK-NEXT: Succs (2): B3 B4
// CHECK: [B6]
// CHECK-NEXT: 1: 0
// CHECK-NEXT: 2: (void)[B6.1] (CStyleCastExpr, ToVoid, void)
// CHECK-NEXT: Preds (1): B7
// CHECK-NEXT: Succs (1): B5
// CHECK: [B7]
// CHECK-NEXT: 1: CFGScopeBegin(b)
// CHECK-NEXT: 2: a
// CHECK-NEXT: 3: [B7.2] (ImplicitCastExpr, NoOp, const A)
// CHECK-NEXT: 4: [B7.3] (CXXConstructExpr, [B7.5], A)
// CHECK-NEXT: 5: A b = a;
// CHECK-NEXT: 6: b
// CHECK-NEXT: 7: [B7.6] (ImplicitCastExpr, NoOp, const class A)
// CHECK-NEXT: 8: [B7.7].operator int
// CHECK-NEXT: 9: [B7.7]
// CHECK-NEXT: 10: [B7.9] (ImplicitCastExpr, UserDefinedConversion, int)
// CHECK-NEXT: 11: [B7.10] (ImplicitCastExpr, IntegralToBoolean, _Bool)
// CHECK-NEXT: T: for (...; [B7.11]; ...)
// CHECK-NEXT: Preds (2): B2 B8
// CHECK-NEXT: Succs (2): B6 B1
// CHECK: [B8]
// CHECK-NEXT: 1: CFGScopeBegin(a)
// CHECK-NEXT: 2: (CXXConstructExpr, [B8.3], A)
// CHECK-NEXT: 3: A a;
// CHECK-NEXT: Preds (1): B9
// CHECK-NEXT: Succs (1): B7
void test_for_inc_conditional() {
for (A a; A b = a; b.p ? b.p++ : 0)
(void)0;
}
// CHECK: [B9 (ENTRY)]
// CHECK-NEXT: Succs (1): B7
// CHECK: [B1]