Merge #1401

1401: macros: properly handles recursive macros r=CohenArthur a=liushuyu

- macros: properly handles recursive macros

Fixes #1084

Co-authored-by: liushuyu <liushuyu011@gmail.com>

5 files changed, 38 insertions, 54 deletions

diff --git a/gcc/rust/expand/rust-attribute-visitor.cc b/gcc/rust/expand/rust-attribute-visitor.cc
index 9332bb6..bbcf2cb 100644
--- a/gcc/rust/expand/rust-attribute-visitor.cc
+++ b/gcc/rust/expand/rust-attribute-visitor.cc
@@ -402,10 +402,7 @@ AttrVisitor::visit (AST::MacroInvocation &macro_invoc)
   // I don't think any macro token trees can be stripped in any way
 
   // TODO: maybe have cfg! macro stripping behaviour here?
-  if (macro_invoc.has_semicolon ())
-    expander.expand_invoc_semi (macro_invoc);
-  else
-    expander.expand_invoc (macro_invoc);
+  expander.expand_invoc (macro_invoc, macro_invoc.has_semicolon ());
 }
 
 void
@@ -3434,8 +3431,17 @@ void
 AttrVisitor::maybe_expand_expr (std::unique_ptr<AST::Expr> &expr)
 {
   auto fragment = expander.take_expanded_fragment (*this);
-  if (fragment.should_expand ())
-    expr = fragment.take_expression_fragment ();
+  unsigned int original_depth = expander.expansion_depth;
+  while (fragment.should_expand ())
+    {
+      expr = fragment.take_expression_fragment ();
+      expander.expansion_depth++;
+      auto new_fragment = expander.take_expanded_fragment (*this);
+      if (new_fragment.is_error ())
+	break;
+      fragment = std::move (new_fragment);
+    }
+  expander.expansion_depth = original_depth;
 }
 
 void
diff --git a/gcc/rust/expand/rust-macro-expand.cc b/gcc/rust/expand/rust-macro-expand.cc
index 189d377..e27adf5 100644
--- a/gcc/rust/expand/rust-macro-expand.cc
+++ b/gcc/rust/expand/rust-macro-expand.cc
@@ -106,7 +106,7 @@ MacroExpander::expand_decl_macro (Location invoc_locus,
 }
 
 void
-MacroExpander::expand_invoc (AST::MacroInvocation &invoc)
+MacroExpander::expand_invoc (AST::MacroInvocation &invoc, bool has_semicolon)
 {
   if (depth_exceeds_recursion_limit ())
     {
@@ -136,54 +136,19 @@ MacroExpander::expand_invoc (AST::MacroInvocation &invoc)
 
   // lookup the rules for this macro
   NodeId resolved_node = UNKNOWN_NODEID;
-  bool found = resolver->get_macro_scope ().lookup (
-    Resolver::CanonicalPath::new_seg (invoc.get_pattern_node_id (),
-				      invoc_data.get_path ().as_string ()),
-    &resolved_node);
-  if (!found)
-    {
-      rust_error_at (invoc.get_locus (), "unknown macro 1");
-      return;
-    }
-
-  // lookup the rules
-  AST::MacroRulesDefinition *rules_def = nullptr;
-  bool ok = mappings->lookup_macro_def (resolved_node, &rules_def);
-  rust_assert (ok);
-
-  auto fragment = AST::ASTFragment::create_error ();
-
-  if (rules_def->is_builtin ())
-    fragment
-      = rules_def->get_builtin_transcriber () (invoc.get_locus (), invoc_data);
+  NodeId source_node = UNKNOWN_NODEID;
+  if (has_semicolon)
+    source_node = invoc.get_macro_node_id ();
   else
-    fragment
-      = expand_decl_macro (invoc.get_locus (), invoc_data, *rules_def, false);
-
-  set_expanded_fragment (std::move (fragment));
-}
-
-// FIXME: Arthur: Refactor these two functions, they're really similar
-void
-MacroExpander::expand_invoc_semi (AST::MacroInvocation &invoc)
-{
-  if (depth_exceeds_recursion_limit ())
-    {
-      rust_error_at (invoc.get_locus (), "reached recursion limit");
-      return;
-    }
-
-  AST::MacroInvocData &invoc_data = invoc.get_invoc_data ();
-
-  // lookup the rules for this macro
-  NodeId resolved_node = UNKNOWN_NODEID;
+    source_node = invoc.get_pattern_node_id ();
   auto seg
-    = Resolver::CanonicalPath::new_seg (invoc.get_macro_node_id (),
+    = Resolver::CanonicalPath::new_seg (source_node,
 					invoc_data.get_path ().as_string ());
+
   bool found = resolver->get_macro_scope ().lookup (seg, &resolved_node);
   if (!found)
     {
-      rust_error_at (invoc.get_locus (), "unknown macro 2: [%s]",
+      rust_error_at (invoc.get_locus (), "unknown macro: [%s]",
 		     seg.get ().c_str ());
       return;
     }
@@ -199,8 +164,8 @@ MacroExpander::expand_invoc_semi (AST::MacroInvocation &invoc)
     fragment
       = rules_def->get_builtin_transcriber () (invoc.get_locus (), invoc_data);
   else
-    fragment
-      = expand_decl_macro (invoc.get_locus (), invoc_data, *rules_def, true);
+    fragment = expand_decl_macro (invoc.get_locus (), invoc_data, *rules_def,
+				  has_semicolon);
 
   set_expanded_fragment (std::move (fragment));
 }
diff --git a/gcc/rust/expand/rust-macro-expand.h b/gcc/rust/expand/rust-macro-expand.h
index a582524..2c3380b 100644
--- a/gcc/rust/expand/rust-macro-expand.h
+++ b/gcc/rust/expand/rust-macro-expand.h
@@ -213,8 +213,7 @@ struct MacroExpander
   /* Expands a macro invocation - possibly make both
    * have similar duck-typed interface and use templates?*/
   // should this be public or private?
-  void expand_invoc (AST::MacroInvocation &invoc);
-  void expand_invoc_semi (AST::MacroInvocation &invoc);
+  void expand_invoc (AST::MacroInvocation &invoc, bool has_semicolon);
 
   // Expands a single declarative macro.
   AST::ASTFragment expand_decl_macro (Location locus,
diff --git a/gcc/testsuite/rust/compile/xfail/macro_return.rs b/gcc/testsuite/rust/compile/macro_return.rs
index c335929..8b06f87 100644
--- a/gcc/testsuite/rust/compile/xfail/macro_return.rs
+++ b/gcc/testsuite/rust/compile/macro_return.rs
@@ -1,4 +1,4 @@
-// { dg-excess-errors "...." { xfail *-*-*-* *-*-* } }
+// { dg-additional-options "-w" }
 
 macro_rules! add {
     ($a:expr) => { $a };
diff --git a/gcc/testsuite/rust/compile/torture/macro_as_expr.rs b/gcc/testsuite/rust/compile/torture/macro_as_expr.rs
new file mode 100644
index 0000000..b0084e7
--- /dev/null
+++ b/gcc/testsuite/rust/compile/torture/macro_as_expr.rs
@@ -0,0 +1,14 @@
+// { dg-additional-options "-w" }
+
+macro_rules! add {
+    ($a:expr) => { $a };
+    ($a:expr, $($b:expr),+) => { $a + add!($($b),*) }
+}
+
+fn main() -> i32 {
+    if add!(add!(1, 2)) > add!(5) {
+        add!(1, add!(2, 3), add!(4))
+    } else {
+        add!(5, add!(6, 7), add!(8), 9) + 10
+    }
+}