[gcc r15-1063] lto: Remove random_seed from section name.

[Michal Jires via Gcc-cvs]

https://gcc.gnu.org/g:346f33e27809ae012696c4731c8ebcec2414dbfb

commit r15-1063-g346f33e27809ae012696c4731c8ebcec2414dbfb
Author: Michal Jires <mji...@suse.cz>
Date:   Tue Jan 9 17:49:34 2024 +0100

    lto: Remove random_seed from section name.
    
    This patch removes suffixes from section names during LTO linking.
    
    These suffixes were originally added for ld -r to work (PR lto/44992).
    They were added to all LTO object files, but are only useful before WPA.
    After that they waste space, and if kept random, make LTO caching 
impossible.
    
    Bootstrapped/regtested on x86_64-pc-linux-gnu
    
    gcc/ChangeLog:
    
            * lto-streamer.cc (lto_get_section_name): Remove suffixes after WPA.
    
    gcc/lto/ChangeLog:
    
            * lto-common.cc (lto_section_with_id): Dont load suffix during 
LTRANS.

Diff:
---
 gcc/lto-streamer.cc   | 11 +++++++++--
 gcc/lto/lto-common.cc |  7 +++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/gcc/lto-streamer.cc b/gcc/lto-streamer.cc
index 8032bbf7108..40ca6b2da1b 100644
--- a/gcc/lto-streamer.cc
+++ b/gcc/lto-streamer.cc
@@ -132,11 +132,18 @@ lto_get_section_name (int section_type, const char *name,
      doesn't confuse the reader with merged sections.
 
      For options don't add a ID, the option reader cannot deal with them
-     and merging should be ok here. */
-  if (section_type == LTO_section_opts)
+     and merging should be ok here.
+
+     LTRANS files (output of wpa, input and output of ltrans) are handled
+     directly inside of linker/lto-wrapper, so name uniqueness for external
+     tools is not needed.
+     Randomness would inhibit incremental LTO.  */
+  if (section_type == LTO_section_opts || flag_ltrans)
     strcpy (post, "");
   else if (f != NULL) 
     sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, f->id);
+  else if (flag_wpa)
+    strcpy (post, "");
   else
     sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, get_random_seed (false)); 
   char *res = concat (section_name_prefix, sep, add, post, NULL);
diff --git a/gcc/lto/lto-common.cc b/gcc/lto/lto-common.cc
index 2ce94cc3282..34aa63b179c 100644
--- a/gcc/lto/lto-common.cc
+++ b/gcc/lto/lto-common.cc
@@ -2176,6 +2176,13 @@ lto_section_with_id (const char *name, unsigned 
HOST_WIDE_INT *id)
 
   if (strncmp (name, section_name_prefix, strlen (section_name_prefix)))
     return 0;
+
+  if (flag_ltrans)
+    {
+      *id = 0;
+      return 1;
+    }
+
   s = strrchr (name, '.');
   if (!s)
     return 0;