[gcc r17-3069] gccrs: Simplify module and extern block emission

https://gcc.gnu.org/g:30ec03e4caa718048bec6cd16330d8426a1dc5bb

commit r17-3069-g30ec03e4caa718048bec6cd16330d8426a1dc5bb
Author: Pierre-Emmanuel Patry <[email protected]>
Date:   Mon Jun 29 13:46:23 2026 +0200

    gccrs: Simplify module and extern block emission
    
    We would have to call two functions, one of which could be forgotten,
    this would also duplicates the condition. This new interface makes
    things a bit simpler.
    
    gcc/rust/ChangeLog:
    
            * metadata/rust-export-metadata.cc (ExportContext::begin_extern_block):
            Delete function.
            (ExportContext::end_extern_block): Likewise.
            (ExportContext::begin_module): Likewise.
            (ExportContext::end_module): Likewise.
            (ExportContext::emit_extern_block): Merge both begin/end within one
            function that calls the visitor in between.
            (ExportContext::emit_module): Likewise.
            * metadata/rust-export-metadata.h: Update function prototypes.
    
    Signed-off-by: Pierre-Emmanuel Patry <[email protected]>

Diff:
---
 gcc/rust/metadata/rust-export-metadata.cc | 37 +++++++++++++------------------
 gcc/rust/metadata/rust-export-metadata.h  |  8 +++----
 2 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/gcc/rust/metadata/rust-export-metadata.cc b/gcc/rust/metadata/rust-export-metadata.cc
index 3388d0e920da..6998319d8575 100644
--- a/gcc/rust/metadata/rust-export-metadata.cc
+++ b/gcc/rust/metadata/rust-export-metadata.cc
@@ -107,30 +107,25 @@ ExportContext::emit_function (AST::Function &fn)
 }
 
 void
-ExportContext::begin_extern_block (AST::ExternBlock &block)
+ExportContext::emit_extern_block (const AST::ExternBlock &block,
+				  std::function<void (void)> sub_visitor)
 {
   public_interface_buffer += "extern \"" + block.get_abi () + "\" {\n";
-}
-
-void
-ExportContext::end_extern_block ()
-{
+  sub_visitor ();
   public_interface_buffer += "}\n";
 }
 
 void
-ExportContext::begin_module (const AST::Module &module)
+ExportContext::emit_module (const AST::Module &module,
+			    std::function<void (void)> sub_visitor)
 {
   if (module.get_visibility ().is_public ())
-    public_interface_buffer
-      += "pub mod " + module.get_name ().as_string () + "{\n";
-}
-
-void
-ExportContext::end_module (const AST::Module &module)
-{
-  if (module.get_visibility ().is_public ())
-    public_interface_buffer += "}\n";
+    {
+      public_interface_buffer
+	+= "pub mod " + module.get_name ().as_string () + "{\n";
+      sub_visitor ();
+      public_interface_buffer += "}\n";
+    }
 }
 
 void
@@ -166,16 +161,14 @@ public:
   }
   void visit (AST::ExternBlock &block) override
   {
-    ctx.begin_extern_block (block);
-    AST::DefaultASTVisitor::visit (block);
-    ctx.end_extern_block ();
+    auto sub_visitor = [&] () { AST::DefaultASTVisitor::visit (block); };
+    ctx.emit_extern_block (block, sub_visitor);
   }
   void visit (AST::Trait &trait) override { ctx.emit_trait (trait); }
   void visit (AST::Module &module) override
   {
-    ctx.begin_module (module);
-    AST::DefaultASTVisitor::visit (module);
-    ctx.end_module (module);
+    auto sub_visitor = [&] () { AST::DefaultASTVisitor::visit (module); };
+    ctx.emit_module (module, sub_visitor);
   }
 
   void visit (AST::UseDeclaration &use_decl) override
diff --git a/gcc/rust/metadata/rust-export-metadata.h b/gcc/rust/metadata/rust-export-metadata.h
index 17dc20a7d5f2..b1e12f2647ff 100644
--- a/gcc/rust/metadata/rust-export-metadata.h
+++ b/gcc/rust/metadata/rust-export-metadata.h
@@ -42,11 +42,11 @@ public:
 
   void emit_trait (AST::Trait &trait);
   void emit_function (AST::Function &fn);
-  void begin_extern_block (AST::ExternBlock &block);
-  void end_extern_block ();
+  void emit_extern_block (const AST::ExternBlock &block,
+			  std::function<void (void)> sub_visitor);
   void emit_use_declaration (AST::UseDeclaration &use_decl);
-  void begin_module (const AST::Module &module);
-  void end_module (const AST::Module &module);
+  void emit_module (const AST::Module &,
+		    std::function<void (void)> sub_visitor);
 
   /**
    * Macros are a bit particular - they only live at the AST level, so we can