Hello Martin,
attached is a proof of concept. I am not sure how I can make the new
section read-only. Currently, it is writable:
.section .gcov_info,"aw"
.align 2
.type .LPBX2, @object
.size .LPBX2, 4
.LPBX2:
.long .LPBX0
I probably need also a patch for the GCC options documentation, test
cases, a GCC bootstrap on Linux, release notes, ...? Do I have to wait
for the GCC 11 development start?
--
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>From 305eb4066742418d3b14ee6e8bec76bfb2835a99 Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.hu...@embedded-brains.de>
Date: Tue, 10 Nov 2020 16:21:07 +0100
Subject: [PATCH] Add -fprofile-info-section support
---
gcc/common.opt | 8 ++++++++
gcc/coverage.c | 19 +++++++++++++++++--
gcc/opts.c | 4 ++++
3 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/gcc/common.opt b/gcc/common.opt
index 7d0e0d9c88a..1b69da681e3 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2268,6 +2268,14 @@ fprofile-generate=
Common Joined RejectNegative
Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
+fprofile-info-section
+Common RejectNegative
+Register a pointer to the profile information in the .gcov_info section.
+
+fprofile-info-section=
+Common Joined RejectNegative Var(profile_info_section)
+Register a pointer to the profile information in the named section.
+
fprofile-partial-training
Common Report Var(flag_profile_partial_training) Optimization
Do not assume that functions never executed during the train run are cold.
diff --git a/gcc/coverage.c b/gcc/coverage.c
index 7711412c3be..ec1c5d3d125 100644
--- a/gcc/coverage.c
+++ b/gcc/coverage.c
@@ -1151,8 +1151,23 @@ coverage_obj_init (void)
ASM_GENERATE_INTERNAL_LABEL (name_buf, "LPBX", 0);
DECL_NAME (gcov_info_var) = get_identifier (name_buf);
- build_init_ctor (gcov_info_type);
- build_gcov_exit_decl ();
+ if (profile_info_section)
+ {
+ tree var = build_decl (BUILTINS_LOCATION,
+ VAR_DECL, NULL_TREE,
+ build_pointer_type (gcov_info_type));
+ TREE_STATIC (var) = 1;
+ ASM_GENERATE_INTERNAL_LABEL (name_buf, "LPBX", 2);
+ DECL_NAME (var) = get_identifier (name_buf);
+ set_decl_section_name (var, profile_info_section);
+ DECL_INITIAL (var) = build_fold_addr_expr (gcov_info_var);
+ varpool_node::finalize_decl (var);
+ }
+ else
+ {
+ build_init_ctor (gcov_info_type);
+ build_gcov_exit_decl ();
+ }
return true;
}
diff --git a/gcc/opts.c b/gcc/opts.c
index 96291e89a49..fd6e669471e 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -2602,6 +2602,10 @@ common_handle_option (struct gcc_options *opts,
SET_OPTION_IF_UNSET (opts, opts_set, flag_ipa_bit_cp, value);
break;
+ case OPT_fprofile_info_section:
+ opts->x_profile_info_section = ".gcov_info";
+ break;
+
case OPT_fpatchable_function_entry_:
{
char *patch_area_arg = xstrdup (arg);
--
2.26.2
