Add plugin API for processing plugin-added input files

Gold plugins may wish to further process an input file added by a plugin. For
example, the plugin may need to assign a unique segment for sections in a
plugin-generated input file. This patch adds a plugin callback that the linker
will call when reading symbols from a new input file added after the
all_symbols_read event (i.e. an input file added by a plugin).

2017-12-11  Stephen Crane  <sjc@immunant.com>

	* plugin-api.h: Add new plugin hook to allow processing of input
	files added by a plugin.
	(ld_plugin_new_input_handler): New function hook type.
	(ld_plugin_register_new_input): New interface.
	(LDPT_REGISTER_NEW_INPUT_HOOK): New enum val.
	(tv_register_new_input): New member.

	* plugin.cc (Plugin::load): Include hooks for register_new_input
	in transfer vector.
	(Plugin::new_input): New function.
	(register_new_input): New function.
	(Plugin_manager::claim_file): Call Plugin::new_input if in
	replacement phase.
	* plugin.h (Plugin::set_new_input_handler): New function.
	* testsuite/plugin_new_section_layout.c: New plugin to test
	new_input plugin API.
	* testsuite/plugin_final_layout.sh: Add new input test.
	* testsuite/Makefile.am (plugin_layout_new_file): New test case.
	* testsuite/Makefile.in: Regenerate.

1 files changed, 19 insertions, 0 deletions

diff --git a/gold/plugin.h b/gold/plugin.h
index 7658668..d591d26 100644
--- a/gold/plugin.h
+++ b/gold/plugin.h
@@ -60,6 +60,7 @@ class Plugin
       claim_file_handler_(NULL),
       all_symbols_read_handler_(NULL),
       cleanup_handler_(NULL),
+      new_input_handler_(NULL),
       cleanup_done_(false)
   { }
 
@@ -78,6 +79,10 @@ class Plugin
   void
   all_symbols_read();
 
+  // Call the new_input handler.
+  void
+  new_input(struct ld_plugin_input_file* plugin_input_file);
+
   // Call the cleanup handler.
   void
   cleanup();
@@ -97,6 +102,11 @@ class Plugin
   set_cleanup_handler(ld_plugin_cleanup_handler handler)
   { this->cleanup_handler_ = handler; }
 
+  // Register a new_input handler.
+  void
+  set_new_input_handler(ld_plugin_new_input_handler handler)
+  { this->new_input_handler_ = handler; }
+
   // Add an argument
   void
   add_option(const char* arg)
@@ -118,6 +128,7 @@ class Plugin
   ld_plugin_claim_file_handler claim_file_handler_;
   ld_plugin_all_symbols_read_handler all_symbols_read_handler_;
   ld_plugin_cleanup_handler cleanup_handler_;
+  ld_plugin_new_input_handler new_input_handler_;
   // TRUE if the cleanup handlers have been called.
   bool cleanup_done_;
 };
@@ -218,6 +229,14 @@ class Plugin_manager
     (*this->current_)->set_all_symbols_read_handler(handler);
   }
 
+  // Register a new_input handler.
+  void
+  set_new_input_handler(ld_plugin_new_input_handler handler)
+  {
+    gold_assert(this->current_ != plugins_.end());
+    (*this->current_)->set_new_input_handler(handler);
+  }
+
   // Register a claim-file handler.
   void
   set_cleanup_handler(ld_plugin_cleanup_handler handler)