input.h: eliminate implicit users of global_dc's file_cache

This patch eliminates the following functions that implicitly used
global_dc's file cache:

  extern char_span location_get_source_line (const char *file_path, int line);
  extern char_span get_source_file_content (const char *file_path);
  extern bool location_missing_trailing_newline (const char *file_path);

in favor of explicitly using a specific file_cache throughout, and only
using global_dc's file_cache in gcc-specific code.

Rather than creating global_dc's file_cache the first time its needed,
this patch simply creates one when a diagnostic_context is initialized,
and eliminates diagnostic_file_cache_init.

No functional change intended.

gcc/c-family/ChangeLog:
	* c-common.cc (c_get_substring_location): Use global_dc's
	file_cache.
	* c-format.cc (get_corrected_substring): Likewise.
	* c-indentation.cc (get_visual_column): Add file_cache param.
	(get_first_nws_vis_column): Likewise.
	(detect_intervening_unindent): Likewise.
	(should_warn_for_misleading_indentation): Use global_dc's
	file_cache.
	(assert_get_visual_column_succeeds): Add file_cache param.
	(ASSERT_GET_VISUAL_COLUMN_SUCCEEDS): Likewise.
	(assert_get_visual_column_fails): Likewise.
	(define ASSERT_GET_VISUAL_COLUMN_FAILS): Likewise.
	(selftest::test_get_visual_column): Create and use a temporary
	file_cache.

gcc/cp/ChangeLog:
	* contracts.cc (build_comment): Use global_dc's file_cache.

gcc/ChangeLog:
	* diagnostic-format-sarif.cc (sarif_builder::get_sarif_column):
	Use m_context's file_cache.
	(sarif_builder::maybe_make_artifact_content_object): Likewise.
	(sarif_builder::get_source_lines): Likewise.
	* diagnostic-show-locus.cc
	(exploc_with_display_col::exploc_with_display_col): Add file_cache
	param.
	(layout::m_file_cache): New field.
	(make_range): Add file_cache param.
	(selftest::test_layout_range_for_single_point): Create and use a
	temporary file_cache.
	(selftest::test_layout_range_for_single_line): Likewise.
	(selftest::test_layout_range_for_multiple_lines): Likewise.
	(layout::layout): Initialize m_file_cache from the context and use it.
	(layout::maybe_add_location_range): Use m_file_cache.
	(layout::calculate_x_offset_display): Likewise.
	(get_affected_range): Add file_cache param.
	(get_printed_columns): Likewise.
	(line_corrections::line_corrections): Likewwise.
	(line_corrections::m_file_cache): New field.
	(source_line::source_line): Add file_cache param.
	(line_corrections::add_hint): Use m_file_cache.
	(layout::print_trailing_fixits): Likewise.
	(layout::print_line): Likewise.
	(selftest::test_layout_x_offset_display_utf8): Create and use a
	temporary file_cache.
	(selftest::test_layout_x_offset_display_tab): Likewise.
	(selftest::test_diagnostic_show_locus_one_liner_utf8): Likewise.
	(selftest::test_add_location_if_nearby): Pass global_dc's
	file_cache to temp_source_file ctor.
	(selftest::test_overlapped_fixit_printing): Create and use a
	temporary file_cache.
	(selftest::test_overlapped_fixit_printing_utf8): Likewise.
	(selftest::test_overlapped_fixit_printing_2): Use dc's file_cache.
	* diagnostic.cc (diagnostic_context::initialize): Always create a
	file_cache.
	(diagnostic_context::initialize_input_context): Assume
	m_file_cache has already been created.
	(diagnostic_context::create_edit_context): Pass m_file_cache to
	edit_context.
	(convert_column_unit): Add file_cache param.
	(diagnostic_context::converted_column): Use context's file_cache.
	(print_parseable_fixits): Add file_cache param.
	(diagnostic_context::report_diagnostic): Use context's file_cache.
	(selftest::test_print_parseable_fixits_none): Create and use a
	temporary file_cache.
	(selftest::test_print_parseable_fixits_insert): Likewise.
	(selftest::test_print_parseable_fixits_remove): Likewise.
	(selftest::test_print_parseable_fixits_replace): Likewise.
	(selftest::test_print_parseable_fixits_bytes_vs_display_columns):
	Likewise.
	* diagnostic.h (diagnostic_context::file_cache_init): Delete.
	(diagnostic_context::get_file_cache): Convert return type from
	pointer to reference.
	* edit-context.cc (edited_file::get_file_cache): New.
	(edited_file::m_edit_context): New.
	(edit_context::edit_context): Add file_cache param.
	(edit_context::get_or_insert_file): Pass this to edited_file's
	ctor.
	(edited_file::edited_file): Add edit_context param.
	(edited_file::print_content): Use get_file_cache.
	(edited_file::print_diff_hunk): Likewise.
	(edited_file::print_run_of_changed_lines): Likewise.
	(edited_file::get_or_insert_line): Likewise.
	(edited_file::get_num_lines): Likewise.
	(edited_line::edited_line): Pass in file_cache and use it.
	(selftest::test_get_content): Create and use a
	temporary file_cache.
	(selftest::test_applying_fixits_insert_before): Likewise.
	(selftest::test_applying_fixits_insert_after): Likewise.
	(selftest::test_applying_fixits_insert_after_at_line_end):
	Likewise.
	(selftest::test_applying_fixits_insert_after_failure): Likewise.
	(selftest::test_applying_fixits_insert_containing_newline):
	Likewise.
	(selftest::test_applying_fixits_growing_replace): Likewise.
	(selftest::test_applying_fixits_shrinking_replace): Likewise.
	(selftest::test_applying_fixits_replace_containing_newline):
	Likewise.
	(selftest::test_applying_fixits_remove): Likewise.
	(selftest::test_applying_fixits_multiple): Likewise.
	(selftest::test_applying_fixits_multiple_lines): Likewise.
	(selftest::test_applying_fixits_modernize_named_init): Likewise.
	(selftest::test_applying_fixits_modernize_named_init): Likewise.
	(selftest::test_applying_fixits_unreadable_file): Likewise.
	(selftest::test_applying_fixits_line_out_of_range): Likewise.
	(selftest::test_applying_fixits_column_validation): Likewise.
	(selftest::test_applying_fixits_column_validation): Likewise.
	(selftest::test_applying_fixits_column_validation): Likewise.
	(selftest::test_applying_fixits_column_validation): Likewise.
	* edit-context.h (edit_context::edit_context): Add file_cache
	param.
	(edit_context::get_file_cache): New.
	(edit_context::m_file_cache): New.
	* final.cc: Include "diagnostic.h".
	(asm_show_source): Use global_dc's file_cache.
	* gcc-rich-location.cc (blank_line_before_p): Add file_cache
	param.
	(use_new_line): Likewise.
	(gcc_rich_location::add_fixit_insert_formatted): Use global dc's
	file_cache.
	* input.cc (diagnostic_file_cache_init): Delete.
	(diagnostic_context::file_cache_init): Delete.
	(diagnostics_file_cache_forcibly_evict_file): Delete.
	(file_cache::missing_trailing_newline_p): New.
	(file_cache::evicted_cache_tab_entry): Don't call
	diagnostic_file_cache_init.
	(location_get_source_line): Delete.
	(get_source_text_between): Add file_cache param.
	(get_source_file_content): Delete.
	(location_missing_trailing_newline): Delete.
	(location_compute_display_column): Add file_cache param.
	(dump_location_info): Create and use temporary file_cache.
	(get_substring_ranges_for_loc): Add file_cache param.
	(get_location_within_string): Likewise.
	(get_source_range_for_char): Likewise.
	(get_num_source_ranges_for_substring): Likewise.
	(selftest::test_reading_source_line): Create and use temporary
	file_cache.
	(selftest::lexer_test::m_file_cache): New field.
	(selftest::assert_char_at_range): Use test.m_file_cache.
	(selftest::assert_num_substring_ranges): Likewise.
	(selftest::assert_has_no_substring_ranges): Likewise.
	(selftest::test_lexer_string_locations_concatenation_2): Likewise.
	* input.h (class file_cache): New forward decl.
	(location_compute_display_column): Add file_cache param.
	(location_get_source_line): Delete.
	(get_source_text_between): Add file_cache param.
	(get_source_file_content): Delete.
	(location_missing_trailing_newline): Delete.
	(file_cache::missing_trailing_newline_p): New decl.
	(diagnostics_file_cache_forcibly_evict_file): Delete.
	* selftest.cc (named_temp_file::named_temp_file): Add file_cache
	param.
	(named_temp_file::~named_temp_file): Optionally evict the file
	from the given file_cache.
	(temp_source_file::temp_source_file): Add file_cache param.
	* selftest.h (class file_cache): New forward decl.
	(named_temp_file::named_temp_file): Add file_cache param.
	(named_temp_file::m_file_cache): New field.
	(temp_source_file::temp_source_file): Add file_cache param.
	* substring-locations.h (get_location_within_string): Add
	file_cache param.

gcc/testsuite/ChangeLog:
	* gcc.dg/plugin/diagnostic_plugin_test_show_locus.c: Use
	global_dc's file cache.
	* gcc.dg/plugin/expensive_selftests_plugin.c: Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>