C++: fix for destructor of while-loop condition

Author: rdmarsh2

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedStmt.qll

@@ -805,12 +805,10 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
   }
 
   override Instruction getALastInstructionInternal() {
-    result = this.getElse().getALastInstruction() or result = this.getThen().getALastInstruction() // FIXME: how do we handle the CFG merge here
+    result = this.getElse().getALastInstruction() or result = this.getThen().getALastInstruction()
   }
 
-  override TranslatedElement getLastChild() {
-    result = this.getElse() or result = this.getThen() // FIXME: how do we handle the CFG merge here
-  }
+  override TranslatedElement getLastChild() { result = this.getElse() or result = this.getThen() }
 
   override TranslatedElement getChildInternal(int id) {
     id = 0 and result = this.getInitialization()
@@ -873,7 +871,7 @@ abstract class TranslatedLoop extends TranslatedStmt, ConditionContext {
   override Loop stmt;
 
   override Instruction getALastInstructionInternal() {
-    result = this.getCondition().getALastInstruction() // FIXME: how do we handle the branch here
+    result = this.getCondition().getALastInstruction()
   }
 
   override TranslatedElement getLastChild() { result = this.getCondition() }
@@ -919,13 +917,36 @@ abstract class TranslatedLoop extends TranslatedStmt, ConditionContext {
 class TranslatedWhileStmt extends TranslatedLoop {
   TranslatedWhileStmt() { stmt instanceof WhileStmt }
 
+  override TranslatedElement getChildInternal(int id) {
+    id = 0 and result = this.getCondition()
+    or
+    id = 1 and result = this.getBody()
+    or
+    exists(int n |
+      result.getAst() = stmt.getImplicitDestructorCall(n) and
+      id = 2 + n
+    )
+  }
+
+  override predicate handlesDestructorsExplicitly() { any() }
+
+  final override Instruction getChildFalseSuccessor(TranslatedCondition child, EdgeKind kind) {
+    child = this.getCondition() and
+    if this.hasAnImplicitDestructorCall()
+    then result = this.getChild(this.getFirstDestructorCallIndex()).getFirstInstruction(kind)
+    else result = this.getParent().getChildSuccessor(this, kind)
+  }
+
   override Instruction getFirstInstruction(EdgeKind kind) {
     result = this.getFirstConditionInstruction(kind)
   }
 
   override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
     child = this.getBody() and
     result = this.getFirstConditionInstruction(kind)
+    or
+    child = this.getChild(this.getFirstDestructorCallIndex()) and
+    result = this.getParent().getChildSuccessor(this, kind)
   }
 }
 

cpp/ql/test/library-tests/ir/ir/aliased_ir.expected

@@ -13246,11 +13246,19 @@ ir.cpp:
 # 2204|     m2204_8(Bool)           = Chi                             : total:m2202_20, partial:m2204_7
 #-----|   Goto (back edge) -> Block 4
 
-# 2206|   Block 6
-# 2206|     v2206_1(void) = NoOp         : 
-# 2193|     v2193_7(void) = ReturnVoid   : 
-# 2193|     v2193_8(void) = AliasedUse   : ~m2202_17
-# 2193|     v2193_9(void) = ExitFunction : 
+# 2204|   Block 6
+# 2204|     r2204_9(glval<Bool>)     = VariableAddress[B]              : 
+# 2204|     r2204_10(glval<unknown>) = FunctionAddress[~Bool]          : 
+# 2204|     v2204_11(void)           = Call[~Bool]                     : func:r2204_10, this:r2204_9
+# 2204|     m2204_12(unknown)        = ^CallSideEffect                 : ~m2202_17
+# 2204|     m2204_13(unknown)        = Chi                             : total:m2202_17, partial:m2204_12
+# 2204|     v2204_14(void)           = ^IndirectReadSideEffect[-1]     : &:r2204_9, m2202_20
+# 2204|     m2204_15(Bool)           = ^IndirectMayWriteSideEffect[-1] : &:r2204_9
+# 2204|     m2204_16(Bool)           = Chi                             : total:m2202_20, partial:m2204_15
+# 2206|     v2206_1(void)            = NoOp                            : 
+# 2193|     v2193_7(void)            = ReturnVoid                      : 
+# 2193|     v2193_8(void)            = AliasedUse                      : ~m2204_13
+# 2193|     v2193_9(void)            = ExitFunction                    : 
 
 perf-regression.cpp:
 #    6| void Big::Big()

cpp/ql/test/library-tests/ir/ir/operand_locations.expected

@@ -10760,7 +10760,7 @@
 | ir.cpp:2182:5:2182:5 | SideEffect | ~m2182_9 |
 | ir.cpp:2193:6:2193:25 | ChiPartial | partial:m2193_3 |
 | ir.cpp:2193:6:2193:25 | ChiTotal | total:m2193_2 |
-| ir.cpp:2193:6:2193:25 | SideEffect | ~m2202_17 |
+| ir.cpp:2193:6:2193:25 | SideEffect | ~m2204_13 |
 | ir.cpp:2193:32:2193:32 | Address | &:r2193_5 |
 | ir.cpp:2195:16:2195:16 | Address | &:r2195_1 |
 | ir.cpp:2195:16:2195:16 | Address | &:r2195_1 |
@@ -10820,13 +10820,23 @@
 | ir.cpp:2203:17:2203:21 | StoreValue | r2203_1 |
 | ir.cpp:2204:9:2204:9 | Address | &:r2204_1 |
 | ir.cpp:2204:9:2204:9 | Address | &:r2204_1 |
+| ir.cpp:2204:9:2204:9 | Address | &:r2204_9 |
+| ir.cpp:2204:9:2204:9 | Address | &:r2204_9 |
 | ir.cpp:2204:9:2204:9 | Arg(this) | this:r2204_1 |
+| ir.cpp:2204:9:2204:9 | Arg(this) | this:r2204_9 |
 | ir.cpp:2204:9:2204:9 | CallTarget | func:r2204_2 |
+| ir.cpp:2204:9:2204:9 | CallTarget | func:r2204_10 |
 | ir.cpp:2204:9:2204:9 | ChiPartial | partial:m2204_4 |
 | ir.cpp:2204:9:2204:9 | ChiPartial | partial:m2204_7 |
+| ir.cpp:2204:9:2204:9 | ChiPartial | partial:m2204_12 |
+| ir.cpp:2204:9:2204:9 | ChiPartial | partial:m2204_15 |
 | ir.cpp:2204:9:2204:9 | ChiTotal | total:m2202_17 |
+| ir.cpp:2204:9:2204:9 | ChiTotal | total:m2202_17 |
+| ir.cpp:2204:9:2204:9 | ChiTotal | total:m2202_20 |
 | ir.cpp:2204:9:2204:9 | ChiTotal | total:m2202_20 |
 | ir.cpp:2204:9:2204:9 | SideEffect | m2202_20 |
+| ir.cpp:2204:9:2204:9 | SideEffect | m2202_20 |
+| ir.cpp:2204:9:2204:9 | SideEffect | ~m2202_17 |
 | ir.cpp:2204:9:2204:9 | SideEffect | ~m2202_17 |
 | perf-regression.cpp:6:3:6:5 | Address | &:r6_5 |
 | perf-regression.cpp:6:3:6:5 | Address | &:r6_5 |

cpp/ql/test/library-tests/ir/ir/raw_ir.expected

@@ -12304,7 +12304,7 @@ ir.cpp:
 # 2202|     mu2202_14(Bool)          = ^IndirectMayWriteSideEffect[-1] : &:r2202_9
 # 2202|     r2202_15(bool)           = CopyValue                       : r2202_11
 # 2202|     v2202_16(void)           = ConditionalBranch               : r2202_15
-#-----|   False -> Block 7
+#-----|   False -> Block 6
 #-----|   True -> Block 5
 
 # 2203|   Block 5
@@ -12326,13 +12326,10 @@ ir.cpp:
 # 2204|     mu2204_10(unknown)      = ^CallSideEffect                 : ~m?
 # 2204|     v2204_11(void)          = ^IndirectReadSideEffect[-1]     : &:r2204_7, ~m?
 # 2204|     mu2204_12(Bool)         = ^IndirectMayWriteSideEffect[-1] : &:r2204_7
-#-----|   Goto -> Block 7
-
-# 2206|   Block 7
-# 2206|     v2206_1(void) = NoOp         : 
-# 2193|     v2193_6(void) = ReturnVoid   : 
-# 2193|     v2193_7(void) = AliasedUse   : ~m?
-# 2193|     v2193_8(void) = ExitFunction : 
+# 2206|     v2206_1(void)           = NoOp                            : 
+# 2193|     v2193_6(void)           = ReturnVoid                      : 
+# 2193|     v2193_7(void)           = AliasedUse                      : ~m?
+# 2193|     v2193_8(void)           = ExitFunction                    : 
 
 perf-regression.cpp:
 #    6| void Big::Big()