Merge branch 'master' into rdmarsh/cpp/ir-flow-through-outparams

Merge IR SSA test additions

Author: rdmarsh2

cpp/ql/src/semmle/code/cpp/exprs/Expr.qll

@@ -2,6 +2,7 @@ import semmle.code.cpp.Element
 private import semmle.code.cpp.Enclosing
 private import semmle.code.cpp.internal.ResolveClass
 private import semmle.code.cpp.internal.AddressConstantExpression
+private import semmle.code.cpp.models.implementations.Allocation
 
 /**
  * A C/C++ expression.
@@ -804,8 +805,10 @@ class NewOrNewArrayExpr extends Expr, @any_new_expr {
    * call the constructor of `T` but will not allocate memory.
    */
   Expr getPlacementPointer() {
-    isStandardPlacementNewAllocator(this.getAllocator()) and
-    result = this.getAllocatorCall().getArgument(1)
+    result =
+      this
+          .getAllocatorCall()
+          .getArgument(this.getAllocator().(OperatorNewAllocationFunction).getPlacementArgument())
   }
 }
 
@@ -1194,12 +1197,6 @@ private predicate convparents(Expr child, int idx, Element parent) {
   )
 }
 
-private predicate isStandardPlacementNewAllocator(Function operatorNew) {
-  operatorNew.getName().matches("operator new%") and
-  operatorNew.getNumberOfParameters() = 2 and
-  operatorNew.getParameter(1).getType() instanceof VoidPointerType
-}
-
 // Pulled out for performance. See QL-796.
 private predicate hasNoConversions(Expr e) { not e.hasConversion() }
 

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll

@@ -206,7 +206,44 @@ abstract class TranslatedCall extends TranslatedExpr {
 
   predicate hasPreciseSideEffect() { exists(getSideEffects()) }
 
-  TranslatedSideEffects getSideEffects() { result.getCall() = expr }
+  final TranslatedSideEffects getSideEffects() { result.getExpr() = expr }
+}
+
+abstract class TranslatedSideEffects extends TranslatedElement {
+  abstract Expr getExpr();
+
+  final override Locatable getAST() { result = getExpr() }
+
+  final override Function getFunction() { result = getExpr().getEnclosingFunction() }
+
+  override TranslatedElement getChild(int i) {
+    result =
+      rank[i + 1](TranslatedSideEffect tse, int isWrite, int index |
+        (
+          tse.getCall() = getExpr() and
+          tse.getArgumentIndex() = index and
+          if tse.isWrite() then isWrite = 1 else isWrite = 0
+        )
+      |
+        tse order by isWrite, index
+      )
+  }
+
+  final override Instruction getChildSuccessor(TranslatedElement te) {
+    exists(int i |
+      getChild(i) = te and
+      if exists(getChild(i + 1))
+      then result = getChild(i + 1).getFirstInstruction()
+      else result = getParent().getChildSuccessor(this)
+    )
+  }
+
+  /**
+   * Gets the `TranslatedFunction` containing this expression.
+   */
+  final TranslatedFunction getEnclosingFunction() {
+    result = getTranslatedFunction(getExpr().getEnclosingFunction())
+  }
 }
 
 /**
@@ -308,56 +345,27 @@ class TranslatedStructorCall extends TranslatedFunctionCall {
   override predicate hasQualifier() { any() }
 }
 
-class TranslatedSideEffects extends TranslatedElement, TTranslatedSideEffects {
-  Call expr;
-
-  TranslatedSideEffects() { this = TTranslatedSideEffects(expr) }
+class TranslatedAllocationSideEffects extends TranslatedSideEffects,
+  TTranslatedAllocationSideEffects {
+  AllocationExpr expr;
 
-  override string toString() { result = "(side effects  for " + expr.toString() + ")" }
+  TranslatedAllocationSideEffects() { this = TTranslatedAllocationSideEffects(expr) }
 
-  override Locatable getAST() { result = expr }
+  final override AllocationExpr getExpr() { result = expr }
 
-  Call getCall() { result = expr }
+  override string toString() { result = "(allocation side effects for " + expr.toString() + ")" }
 
-  override TranslatedElement getChild(int i) {
-    result =
-      rank[i + 1](TranslatedSideEffect tse, int isWrite, int index |
-        (
-          tse.getCall() = getCall() and
-          tse.getArgumentIndex() = index and
-          if tse.isWrite() then isWrite = 1 else isWrite = 0
-        )
-      |
-        tse order by isWrite, index
-      )
-  }
-
-  override Instruction getChildSuccessor(TranslatedElement te) {
-    exists(int i |
-      getChild(i) = te and
-      if exists(getChild(i + 1))
-      then result = getChild(i + 1).getFirstInstruction()
-      else result = getParent().getChildSuccessor(this)
-    )
-  }
+  override Instruction getFirstInstruction() { result = getInstruction(OnlyInstructionTag()) }
 
   override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType type) {
-    expr.getTarget() instanceof AllocationFunction and
     opcode instanceof Opcode::InitializeDynamicAllocation and
     tag = OnlyInstructionTag() and
     type = getUnknownType()
   }
 
-  override Instruction getFirstInstruction() {
-    if expr.getTarget() instanceof AllocationFunction
-    then result = getInstruction(OnlyInstructionTag())
-    else result = getChild(0).getFirstInstruction()
-  }
-
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) {
     tag = OnlyInstructionTag() and
     kind = gotoEdge() and
-    expr.getTarget() instanceof AllocationFunction and
     if exists(getChild(0))
     then result = getChild(0).getFirstInstruction()
     else result = getParent().getChildSuccessor(this)
@@ -371,23 +379,34 @@ class TranslatedSideEffects extends TranslatedElement, TTranslatedSideEffects {
 
   override Instruction getPrimaryInstructionForSideEffect(InstructionTag tag) {
     tag = OnlyInstructionTag() and
-    result = getTranslatedExpr(expr).getInstruction(CallTag())
+    if expr instanceof NewOrNewArrayExpr
+    then result = getTranslatedAllocatorCall(expr).getInstruction(CallTag())
+    else result = getTranslatedExpr(expr).getInstruction(CallTag())
   }
+}
 
-  /**
-   * Gets the `TranslatedFunction` containing this expression.
-   */
-  final TranslatedFunction getEnclosingFunction() {
-    result = getTranslatedFunction(expr.getEnclosingFunction())
-  }
+class TranslatedCallSideEffects extends TranslatedSideEffects, TTranslatedCallSideEffects {
+  Call expr;
 
-  /**
-   * Gets the `Function` containing this expression.
-   */
-  override Function getFunction() { result = expr.getEnclosingFunction() }
+  TranslatedCallSideEffects() { this = TTranslatedCallSideEffects(expr) }
+
+  override string toString() { result = "(side effects  for " + expr.toString() + ")" }
+
+  override Call getExpr() { result = expr }
+
+  override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType type) { none() }
+
+  override Instruction getFirstInstruction() { result = getChild(0).getFirstInstruction() }
+
+  override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) { none() }
+
+  override Instruction getPrimaryInstructionForSideEffect(InstructionTag tag) {
+    tag = OnlyInstructionTag() and
+    result = getTranslatedExpr(expr).getInstruction(CallTag())
+  }
 }
 
-class TranslatedStructorCallSideEffects extends TranslatedSideEffects {
+class TranslatedStructorCallSideEffects extends TranslatedCallSideEffects {
   TranslatedStructorCallSideEffects() { getParent().(TranslatedStructorCall).hasQualifier() }
 
   override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType t) {

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedElement.qll

@@ -442,11 +442,22 @@ newtype TTranslatedElement =
   // The declaration/initialization part of a `ConditionDeclExpr`
   TTranslatedConditionDecl(ConditionDeclExpr expr) { not ignoreExpr(expr) } or
   // The side effects of a `Call`
-  TTranslatedSideEffects(Call expr) {
-    exists(TTranslatedArgumentSideEffect(expr, _, _, _)) or
-    expr instanceof ConstructorCall or
-    expr.getTarget() instanceof AllocationFunction
-  } or // A precise side effect of an argument to a `Call`
+  TTranslatedCallSideEffects(Call expr) {
+    // Exclude allocations such as `malloc` (which happen to also be function calls).
+    // Both `TranslatedCallSideEffects` and `TranslatedAllocationSideEffects` generate
+    // the same side effects for its children as they both extend the `TranslatedSideEffects`
+    // class.
+    // Note: We can separate allocation side effects and call side effects into two
+    // translated elements as no call can be both a `ConstructorCall` and an `AllocationExpr`.
+    not expr instanceof AllocationExpr and
+    (
+      exists(TTranslatedArgumentSideEffect(expr, _, _, _)) or
+      expr instanceof ConstructorCall
+    )
+  } or
+  // The side effects of an allocation, i.e. `new`, `new[]` or `malloc`
+  TTranslatedAllocationSideEffects(AllocationExpr expr) or
+  // A precise side effect of an argument to a `Call`
   TTranslatedArgumentSideEffect(Call call, Expr expr, int n, boolean isWrite) {
     (
       expr = call.getArgument(n).getFullyConverted()

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedExpr.qll

@@ -1649,6 +1649,11 @@ class TranslatedAllocatorCall extends TTranslatedAllocatorCall, TranslatedDirect
 
   final override int getNumberOfArguments() {
     result = expr.getAllocatorCall().getNumberOfArguments()
+    or
+    // Make sure there's a result even when there is no allocator, as otherwise
+    // TranslatedCall::getChild() will not return the side effects for this call.
+    not exists(expr.getAllocatorCall()) and
+    result = 0
   }
 
   final override TranslatedExpr getArgument(int index) {

cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll

@@ -215,6 +215,40 @@ class SizelessAllocationFunction extends AllocationFunction {
   }
 }
 
+/**
+ * An `operator new` or `operator new[]` function that may be associated with `new` or
+ * `new[]` expressions.  Note that `new` and `new[]` are not function calls, but these
+ * functions may also be called directly.
+ */
+class OperatorNewAllocationFunction extends AllocationFunction {
+  OperatorNewAllocationFunction() {
+    exists(string name |
+      hasGlobalName(name) and
+      (
+        // operator new(bytes, ...)
+        name = "operator new"
+        or
+        // operator new[](bytes, ...)
+        name = "operator new[]"
+      )
+    )
+  }
+
+  override int getSizeArg() { result = 0 }
+
+  override predicate requiresDealloc() { not exists(getPlacementArgument()) }
+
+  /**
+   * Gets the position of the placement pointer if this is a placement
+   * `operator new` function.
+   */
+  int getPlacementArgument() {
+    getNumberOfParameters() = 2 and
+    getParameter(1).getType() instanceof VoidPointerType and
+    result = 1
+  }
+}
+
 /**
  * An allocation expression that is a function call, such as call to `malloc`.
  */
@@ -227,7 +261,9 @@ class CallAllocationExpr extends AllocationExpr, FunctionCall {
     not (
       exists(target.getReallocPtrArg()) and
       getArgument(target.getSizeArg()).getValue().toInt() = 0
-    )
+    ) and
+    // these are modelled directly (and more accurately), avoid duplication
+    not exists(NewOrNewArrayExpr new | new.getAllocatorCall() = this)
   }
 
   override Expr getSizeExpr() { result = getArgument(target.getSizeArg()) }

cpp/ql/src/semmle/code/cpp/models/implementations/Deallocation.qll

@@ -79,6 +79,28 @@ class StandardDeallocationFunction extends DeallocationFunction {
   override int getFreedArg() { result = freedArg }
 }
 
+/**
+ * An `operator delete` or `operator delete[]` function that may be associated
+ * with `delete` or `delete[]` expressions.  Note that `delete` and `delete[]`
+ * are not function calls, but these functions may also be called directly.
+ */
+class OperatorDeleteDeallocationFunction extends DeallocationFunction {
+  OperatorDeleteDeallocationFunction() {
+    exists(string name |
+      hasGlobalName(name) and
+      (
+        // operator delete(pointer, ...)
+        name = "operator delete"
+        or
+        // operator delete[](pointer, ...)
+        name = "operator delete[]"
+      )
+    )
+  }
+
+  override int getFreedArg() { result = 0 }
+}
+
 /**
  * An deallocation expression that is a function call, such as call to `free`.
  */

cpp/ql/test/library-tests/allocators/allocators.cpp

@@ -143,3 +143,9 @@ void multidimensionalNew(int x, int y) {
   auto p2 = new char[20][20];
   auto p3 = new char[x][30][30];
 }
+
+void directOperatorCall() {
+	void *ptr;
+	ptr = operator new(sizeof(int));
+	operator delete(ptr);
+}