Revert "Merge pull request #12125 from jketema/unique-function"

This reverts commit 9c039c4a08, reversing
changes made to ecd2003c14.

cpp/ql/lib/semmle/code/cpp/Element.qll

@@ -7,7 +7,6 @@ import semmle.code.cpp.Location
 private import semmle.code.cpp.Enclosing
 private import semmle.code.cpp.internal.ResolveClass
 private import semmle.code.cpp.internal.ResolveGlobalVariable
-private import semmle.code.cpp.internal.ResolveFunction
 
 /**
  * Get the `Element` that represents this `@element`.
@@ -31,14 +30,11 @@ pragma[inline]
 @element unresolveElement(Element e) {
   not result instanceof @usertype and
   not result instanceof @variable and
-  not result instanceof @function and
   result = e
   or
   e = resolveClass(result)
   or
   e = resolveGlobalVariable(result)
-  or
-  e = resolveFunction(result)
 }
 
 /**

cpp/ql/lib/semmle/code/cpp/Function.qll

@@ -9,7 +9,6 @@ import semmle.code.cpp.exprs.Call
 import semmle.code.cpp.metrics.MetricFunction
 import semmle.code.cpp.Linkage
 private import semmle.code.cpp.internal.ResolveClass
-private import semmle.code.cpp.internal.ResolveFunction
 
 /**
  * A C/C++ function [N4140 8.3.5]. Both member functions and non-member
@@ -26,8 +25,6 @@ private import semmle.code.cpp.internal.ResolveFunction
  * in more detail in `Declaration.qll`.
  */
 class Function extends Declaration, ControlFlowNode, AccessHolder, @function {
-  Function() { isFunction(underlyingElement(this)) }
-
   override string getName() { functions(underlyingElement(this), result, _) }
 
   /**

cpp/ql/lib/semmle/code/cpp/controlflow/internal/ConstantExprs.qll

@@ -110,8 +110,8 @@ private predicate loopConditionAlwaysUponEntry(ControlFlowNode loop, Expr condit
  * should be in this relation.
  */
 pragma[noinline]
-private predicate isFunction(@element el) {
-  el instanceof @function
+private predicate isFunction(Element el) {
+  el instanceof Function
   or
   el.(Expr).getParent() = el
 }
@@ -122,7 +122,7 @@ private predicate isFunction(@element el) {
  */
 pragma[noopt]
 private predicate callHasNoTarget(@funbindexpr fc) {
-  exists(@function f |
+  exists(Function f |
     funbind(fc, f) and
     not isFunction(f)
   )

cpp/ql/lib/semmle/code/cpp/internal/ResolveFunction.qll

@@ -1,57 +0,0 @@
-private predicate hasDefinition(@function f) {
-  exists(@fun_decl fd | fun_decls(fd, f, _, _, _) | fun_def(fd))
-}
-
-private predicate onlyOneCompleteFunctionExistsWithMangledName(@mangledname name) {
-  strictcount(@function f | hasDefinition(f) and mangled_name(f, name)) = 1
-}
-
-/** Holds if `f` is a unique function with a definition named `name`. */
-private predicate isFunctionWithMangledNameAndWithDefinition(@mangledname name, @function f) {
-  hasDefinition(f) and
-  mangled_name(f, name) and
-  onlyOneCompleteFunctionExistsWithMangledName(name)
-}
-
-/** Holds if `f` is a function without a definition named `name`. */
-private predicate isFunctionWithMangledNameAndWithoutDefinition(@mangledname name, @function f) {
-  not hasDefinition(f) and
-  mangled_name(f, name)
-}
-
-/**
- * Holds if `incomplete` is a function without a definition, and there exists
- * a unique function `complete` with the same name that does have a definition.
- */
-private predicate hasTwinWithDefinition(@function incomplete, @function complete) {
-  not function_instantiation(incomplete, complete) and
-  (
-    not compgenerated(incomplete) or
-    not compgenerated(complete)
-  ) and
-  exists(@mangledname name |
-    isFunctionWithMangledNameAndWithoutDefinition(name, incomplete) and
-    isFunctionWithMangledNameAndWithDefinition(name, complete)
-  )
-}
-
-import Cached
-
-cached
-private module Cached {
-  /**
-   * If `f` is a function without a definition, and there exists a unique
-   * function with the same name that does have a definition, then the
-   * result is that unique function. Otherwise, the result is `f`.
-   */
-  cached
-  @function resolveFunction(@function f) {
-    hasTwinWithDefinition(f, result)
-    or
-    not hasTwinWithDefinition(f, _) and
-    result = f
-  }
-
-  cached
-  predicate isFunction(@function f) { f = resolveFunction(_) }
-}

cpp/ql/lib/semmle/code/cpp/internal/ResolveGlobalVariable.qll

@@ -24,8 +24,8 @@ private predicate isGlobalWithMangledNameAndWithoutDefinition(@mangledname name,
  * a unique global variable `complete` with the same name that does have a definition.
  */
 private predicate hasTwinWithDefinition(@globalvariable incomplete, @globalvariable complete) {
-  not variable_instantiation(incomplete, complete) and
   exists(@mangledname name |
+    not variable_instantiation(incomplete, complete) and
     isGlobalWithMangledNameAndWithoutDefinition(name, incomplete) and
     isGlobalWithMangledNameAndWithDefinition(name, complete)
   )