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

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

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 9b5db44..64a4fff 100644 (file)
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -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.

diff --git a/clang/test/Analysis/auto-obj-dtors-cfg-output.cpp b/clang/test/Analysis/auto-obj-dtors-cfg-output.cpp
index 5c73ffb..96b9a55 100644 (file)
--- a/clang/test/Analysis/auto-obj-dtors-cfg-output.cpp
+++ b/clang/test/Analysis/auto-obj-dtors-cfg-output.cpp
@@ -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]

diff --git a/clang/test/Analysis/lifetime-cfg-output.cpp b/clang/test/Analysis/lifetime-cfg-output.cpp
index 6aa61da..f9015e0 100644 (file)
--- a/clang/test/Analysis/lifetime-cfg-output.cpp
+++ b/clang/test/Analysis/lifetime-cfg-output.cpp
@@ -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]

diff --git a/clang/test/Analysis/scopes-cfg-output.cpp b/clang/test/Analysis/scopes-cfg-output.cpp
index bc20fab..6877d12 100644 (file)
--- a/clang/test/Analysis/scopes-cfg-output.cpp
+++ b/clang/test/Analysis/scopes-cfg-output.cpp
@@ -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]
@@ -675,6 +678,71 @@ void test_for_jumps() {
 }
 
 // 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]
 // CHECK-NEXT:  l1: