Merge pull request #11262 from rdmarsh2/rdmarsh2/cpp/deprecate-ast-gvn

C++: deprecate AST-based GVN

Author: jketema

cpp/ql/lib/change-notes/2022-11-14-deprecate-ast-gvn.md

@@ -0,0 +1,6 @@
+---
+category: deprecated
+---
+
+
+* Deprecated `semmle.code.cpp.valuenumbering.GlobalValueNumberingImpl`. Use `semmle.code.cpp.valuenumbering.GlobalValueNumbering`, which exposes the same API.

cpp/ql/lib/semmle/code/cpp/valuenumbering/GlobalValueNumberingImpl.qll

@@ -1,4 +1,8 @@
 /**
+ * DEPRECATED: This library has been replaced with a newer version which
+ * provides better performance and precision. Use
+ * `semmle.code.cpp.valuenumbering.GlobalValueNumbering` instead.
+ *
  * Provides an implementation of Global Value Numbering.
  * See https://en.wikipedia.org/wiki/Global_value_numbering
  *
@@ -221,7 +225,7 @@ private newtype GvnBase =
  * expression with this `GVN` and using its `toString` and `getLocation`
  * methods.
  */
-class GVN extends GvnBase {
+deprecated class GVN extends GvnBase {
   GVN() { this instanceof GvnBase }
 
   /** Gets an expression that has this GVN. */
@@ -503,7 +507,7 @@ private predicate mk_Deref(GVN p, ControlFlowNode dominator, PointerDereferenceE
 
 /** Gets the global value number of expression `e`. */
 cached
-GVN globalValueNumber(Expr e) {
+deprecated GVN globalValueNumber(Expr e) {
   exists(int val, Type t |
     mk_IntConst(val, t, e) and
     result = GVN_IntConst(val, t)

cpp/ql/test/library-tests/valuenumbering/GlobalValueNumbering/ast_gvn.expected

@@ -1,3 +1,4 @@
+WARNING: Type GVN has been deprecated and may be removed in future (ast_gvn.ql:4,6-9)
 | test.cpp:5:3:5:3 | x | 5:c3-c3 6:c3-c3 |
 | test.cpp:5:7:5:8 | p0 | 5:c7-c8 6:c7-c8 |
 | test.cpp:5:7:5:13 | ... + ... | 5:c7-c13 6:c7-c13 7:c7-c7 |

cpp/ql/test/library-tests/valuenumbering/GlobalValueNumbering/ast_uniqueness.expected

@@ -0,0 +1,3 @@
+WARNING: Predicate globalValueNumber has been deprecated and may be removed in future (ast_uniqueness.ql:7,13-30)
+WARNING: Predicate globalValueNumber has been deprecated and may be removed in future (ast_uniqueness.ql:8,30-47)
+WARNING: Type GVN has been deprecated and may be removed in future (ast_uniqueness.ql:8,18-21)

cpp/ql/test/library-tests/valuenumbering/GlobalValueNumbering/diff_ir_expr.expected

@@ -1,3 +1,4 @@
+WARNING: Predicate globalValueNumber has been deprecated and may be removed in future (diff_ir_expr.ql:8,29-51)
 | test.cpp:5:3:5:13 | ... = ... | test.cpp:5:3:5:13 | ... = ... | AST only |
 | test.cpp:6:3:6:13 | ... = ... | test.cpp:6:3:6:13 | ... = ... | AST only |
 | test.cpp:7:3:7:7 | ... = ... | test.cpp:7:3:7:7 | ... = ... | AST only |