Merge #985

985: Parse macro!(); as MacroInvocation with semicolon r=CohenArthur a=CohenArthur

When parsing a macro invocation as a statement, the parser would parse
an expression and then try parsing a semicolon. Since no actual
lookahead was done (which is a good thing), we couldn't convert a
`MacroInvocation` to a `MacroInvocationSemi` after the fact.

Since, unlike function calls, macro invocations can act differently
based on whether or not they are followed by a semicolon, we actually
need to differentiate between the two up until expansion.

This commits adds a new virtual method for ExprWithoutBlock when
converting to ExprStmtWithoutBlock so that classes inheriting
ExprWithoutBlock can specify a new behavior. In the case of our
MacroInvocation class, it simply means toggling a boolean: If we're
converting a macro from an expression to a statement, it must mean that
it should contain a semicolon.

Closes #941 

Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>

1 files changed, 9 insertions, 26 deletions

diff --git a/gcc/rust/expand/rust-macro-expand.cc b/gcc/rust/expand/rust-macro-expand.cc
index a4ed36b..26f584d 100644
--- a/gcc/rust/expand/rust-macro-expand.cc
+++ b/gcc/rust/expand/rust-macro-expand.cc
@@ -310,7 +310,8 @@ public:
   {
     // supposedly does not require - cfg does nothing
   }
-  void visit (AST::MacroInvocationSemi &macro_invoc) override
+
+  void visit (AST::MacroInvocation &macro_invoc) override
   {
     // initial strip test based on outer attrs
     expander.expand_cfg_attrs (macro_invoc.get_outer_attrs ());
@@ -326,9 +327,13 @@ public:
 
     // TODO: maybe have cfg! macro stripping behaviour here?
 
-    expander.expand_invoc_semi (macro_invoc);
+    if (macro_invoc.has_semicolon ())
+      expander.expand_invoc_semi (macro_invoc);
+    else
+      expander.expand_invoc (macro_invoc);
 
-    // we need to visit the expanded fragments since it may need cfg expansion
+    // we need to visit the expanded fragments since it may need cfg
+    // expansion
     // and it may be recursive
     for (auto &node : macro_invoc.get_fragment ().get_nodes ())
       node.accept_vis (*this);
@@ -2534,28 +2539,6 @@ public:
     expander.mappings->insert_macro_def (&rules_def);
   }
 
-  void visit (AST::MacroInvocation &macro_invoc) override
-  {
-    // FIXME
-    // we probably need another recurision check here
-
-    // initial strip test based on outer attrs
-    expander.expand_cfg_attrs (macro_invoc.get_outer_attrs ());
-    if (expander.fails_cfg_with_expand (macro_invoc.get_outer_attrs ()))
-      {
-	macro_invoc.mark_for_strip ();
-	return;
-      }
-
-    // I don't think any macro token trees can be stripped in any way
-    expander.expand_invoc (macro_invoc);
-
-    // we need to visit the expanded fragments since it may need cfg expansion
-    // and it may be recursive
-    for (auto &node : macro_invoc.get_fragment ().get_nodes ())
-      node.accept_vis (*this);
-  }
-
   void visit (AST::MetaItemPath &) override {}
   void visit (AST::MetaItemSeq &) override {}
   void visit (AST::MetaWord &) override {}
@@ -3209,7 +3192,7 @@ MacroExpander::expand_invoc (AST::MacroInvocation &invoc)
 }
 
 void
-MacroExpander::expand_invoc_semi (AST::MacroInvocationSemi &invoc)
+MacroExpander::expand_invoc_semi (AST::MacroInvocation &invoc)
 {
   if (depth_exceeds_recursion_limit ())
     {