Re: [PATCH] Add debug support for merging identical functions (aka ICF)

[Cary Coutant <ccoutant at google dot com>]

> http://gcc.gnu.org/ml/gcc-patches/2009-07/msg01702.html

Here's a refresh of this patch, with a small change I added to the
direct call table to record a pointer to the caller's debug info,
which I found is necessary to handle a recursive case where a pair of
routines C and D get folded together, thus enabling a second pair of
routines A and B to be folded, where A calls C and B calls D.

-cary


gcc/ChangeLog:
	Add support for debugging with ICF (Identical Code Folding).
	* calls.c (debug.h): New #include.
	(emit_call_1): Call virtual_call_token debug hook.
	* common.opt (-fenable-icf-debug): New option.
	* dwarf2out.c (dwarf2_debug_hooks): Add entries for new hooks (two
	locations in the source).
	(poc_label_num): New variable.
	(dcall_entry, vcall_entry): New typedefs.
	(dcall_table, vcall_table): New variables.
	(struct vcall_insn): New type.
	(vcall_insn_table): New variable.
	(DEBUG_DCALL_SECTION, DEBUG_VCALL_SECTION): New macros.
	(size_of_dcall_table): New function.
	(output_dcall_table): New function.
	(size_of_vcall_table): New function.
	(output_vcall_table): New function.
	(dwarf2out_direct_call): New function.
	(vcall_insn_table_hash): New function.
	(vcall_insn_table_eq): New function.
	(dwarf2out_virtual_call_token): New function.
	(dwarf2out_virtual_call): New function.
	(dwarf2out_init): Allocate new tables and sections.
	(prune_unused_types): Mark DIEs referenced from direct call table.
	(dwarf2out_finish): Output direct and virtual call tables.
	* final.c (final_scan_insn): Call direct_call and virtual_call
	debug hooks.
	* debug.h (struct gcc_debug_hooks): Add direct_call,
	virtual_call_token, virtual_call hooks.
	(debug_nothing_uid): New function.
	* debug.c (do_nothing_debug_hooks): Add dummy entries for new hooks.
	(debug_nothing_uid): New function.
	* dbxout.c (dbx_debug_hooks): Add dummy entries for new hooks.
	* sdbout.c (sdb_debug_hooks): Likewise.
	* vmsdbgout.c (vmsdbg_debug_hooks): Likewise.
	* doc/invoke.texi (-fenable-icf-debug): New option.

gcc/testsuite/ChangeLog:
	Add support for debugging with ICF (Identical Code Folding).
	* g++.dg/debug/dwarf2/icf.C: New test.

Attachment: gcc-icf-patch-2.txt
Description: Text document