C++: Deduplicate AllocationExprs.

geoffw0 · geoffw0 · commit 254c877d0a77 · 2020-03-31T11:05:50.000+01:00
diff --git a/cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll b/cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll
@@ -261,6 +261,9 @@ class CallAllocationExpr extends AllocationExpr, FunctionCall {
       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()) }
diff --git a/cpp/ql/test/library-tests/allocators/allocators.expected b/cpp/ql/test/library-tests/allocators/allocators.expected
@@ -61,17 +61,13 @@ allocationFunctions
 | file://:0:0:0:0 | operator new[] | getSizeArg = 0, requiresDealloc |
 allocationExprs
 | allocators.cpp:49:3:49:9 | new | getSizeBytes = 4, requiresDealloc |
-| allocators.cpp:50:3:50:15 | call to operator new | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:50:3:50:15 | new | getSizeBytes = 4, requiresDealloc |
 | allocators.cpp:51:3:51:11 | new | getSizeBytes = 4, requiresDealloc |
 | allocators.cpp:52:3:52:14 | new | getSizeBytes = 8, requiresDealloc |
-| allocators.cpp:53:3:53:27 | call to operator new | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:53:3:53:27 | new | getSizeBytes = 8, requiresDealloc |
 | allocators.cpp:54:3:54:17 | new | getSizeBytes = 256, requiresDealloc |
-| allocators.cpp:55:3:55:25 | call to operator new | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:55:3:55:25 | new | getSizeBytes = 256, requiresDealloc |
 | allocators.cpp:68:3:68:12 | new[] | getSizeExpr = n, getSizeMult = 4, requiresDealloc |
-| allocators.cpp:69:3:69:18 | call to operator new[] | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:69:3:69:18 | new[] | getSizeExpr = n, getSizeMult = 4, requiresDealloc |
 | allocators.cpp:70:3:70:15 | new[] | getSizeExpr = n, getSizeMult = 8, requiresDealloc |
 | allocators.cpp:71:3:71:20 | new[] | getSizeExpr = n, getSizeMult = 256, requiresDealloc |
@@ -80,13 +76,9 @@ allocationExprs
 | allocators.cpp:108:3:108:19 | new[] | getSizeExpr = n, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:109:3:109:35 | new | getSizeBytes = 128, requiresDealloc |
 | allocators.cpp:110:3:110:37 | new[] | getSizeBytes = 1280, requiresDealloc |
-| allocators.cpp:129:3:129:21 | call to operator new | getSizeExpr = <error expr>, getSizeMult = 1 |
 | allocators.cpp:129:3:129:21 | new | getSizeBytes = 4 |
-| allocators.cpp:132:3:132:17 | call to operator new[] | getSizeExpr = <error expr>, getSizeMult = 1 |
 | allocators.cpp:132:3:132:17 | new[] | getSizeBytes = 4 |
-| allocators.cpp:135:3:135:26 | call to operator new | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:135:3:135:26 | new | getSizeBytes = 4, requiresDealloc |
-| allocators.cpp:136:3:136:26 | call to operator new[] | getSizeExpr = <error expr>, getSizeMult = 1, requiresDealloc |
 | allocators.cpp:136:3:136:26 | new[] | getSizeBytes = 8, requiresDealloc |
 | allocators.cpp:142:13:142:27 | new[] | getSizeExpr = x, getSizeMult = 10, requiresDealloc |
 | allocators.cpp:143:13:143:28 | new[] | getSizeBytes = 400, requiresDealloc |

Original file line number	Diff line number	Diff line change
`@@ -261,6 +261,9 @@ class CallAllocationExpr extends AllocationExpr, FunctionCall {`
`261`	`261`	`exists(target.getReallocPtrArg()) and`
`262`	`262`	`getArgument(target.getSizeArg()).getValue().toInt() = 0`
`263`	`263`	`)`
	`264`	`+ and`
	`265`	`+ // these are modelled directly (and more accurately), avoid duplication`
	`266`	`+ not exists(NewOrNewArrayExpr new \| new.getAllocatorCall() = this)`
`264`	`267`	`}`
`265`	`268`
`266`	`269`	`override Expr getSizeExpr() { result = getArgument(target.getSizeArg()) }`