PR 22843: ld, gold: Add --dependency-file option.

gold/
	* options.h (class General_options): Add --dependency-file option.
	* fileread.cc (File_read::files_read): New static variable.
	(File_read::open): Add the file to the files_read list.
	(File_read::record_file_read): New static member function.
	(File_read::write_dependency_file): New static member function.
	* fileread.h (class File_read): Declare them.
	* layout.cc (Layout::read_layout_from_file): Call record_file_read.
	(Close_task_runner::run): Call write_dependency_file if
	--dependency-file was passed.

ld/
	* NEWS: Note --dependency-file.
	* ld.texi (Options): Document --dependency-file.
	* ldlex.h (enum option_values): Add OPTION_DEPENDENCY_FILE.
	* ld.h (ld_config_type): New member dependency_file.
	* lexsup.c (ld_options, parse_args): Parse --dependency-file.
	* ldmain.c (struct dependency_file): New type.
	(dependency_files, dependency_files_tail): New static variables.
	(track_dependency_files): New function.
	(write_dependency_file): New function.
	(main): Call it when --dependency-file was passed.
	* ldfile.c (ldfile_try_open_bfd): Call track_dependency_files.
	(ldfile_open_command_file_1): Likewise.
	* ldelf.c (ldelf_try_needed): Likewise.
	* pe-dll.c (pe_implied_import_dll): Likewise.

1 files changed, 30 insertions, 0 deletions

diff --git a/gold/fileread.cc b/gold/fileread.cc
index bebe0aba8d0..f5ca719360d 100644
--- a/gold/fileread.cc
+++ b/gold/fileread.cc
@@ -124,6 +124,7 @@ static Initialize_lock file_counts_initialize_lock(&file_counts_lock);
 unsigned long long File_read::total_mapped_bytes;
 unsigned long long File_read::current_mapped_bytes;
 unsigned long long File_read::maximum_mapped_bytes;
+std::vector<std::string> File_read::files_read;
 
 // Class File_read::View.
 
@@ -211,6 +212,8 @@ File_read::open(const Task* task, const std::string& name)
       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
 		 this->name_.c_str());
       this->token_.add_writer(task);
+      Hold_optional_lock hl(file_counts_lock);
+      record_file_read(this->name_);
     }
 
   return this->descriptor_ >= 0;
@@ -1138,4 +1141,31 @@ Input_file::open_binary(const Task* task, const std::string& name)
 			  binary_to_elf.converted_size());
 }
 
+void
+File_read::record_file_read(const std::string& name)
+{
+  File_read::files_read.push_back(name);
+}
+
+void
+File_read::write_dependency_file(const char* dependency_file_name,
+				 const char* output_file_name)
+{
+  FILE *depfile = fopen(dependency_file_name, "w");
+
+  fprintf(depfile, "%s:", output_file_name);
+  for (std::vector<std::string>::const_iterator it = files_read.begin();
+       it != files_read.end();
+       ++it)
+    fprintf(depfile, " \\\n  %s", it->c_str());
+  fprintf(depfile, "\n");
+
+  for (std::vector<std::string>::const_iterator it = files_read.begin();
+       it != files_read.end();
+       ++it)
+    fprintf(depfile, "\n%s:\n", it->c_str());
+
+  fclose(depfile);
+}
+
 } // End namespace gold.