Do not emit __gnu_lto_v1 symbol.
diff mbox series

Message ID e9d179d0-c078-88a4-3061-c2f726917432@suse.cz
State New
Headers show
Series
  • Do not emit __gnu_lto_v1 symbol.
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Commit Message

Martin Liška July 15, 2019, 1:30 p.m. UTC
Hi.

The patch is about removal of the emission of __gnu_lto_v1.
The symbol should not be needed any longer for GCC driver.

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

2019-07-15  Martin Liska  <mliska@suse.cz>

	* config/avr/avr.c (avr_asm_output_aligned_decl_common): Update
	comment.
	* toplev.c (compile_file): Do not emit __gnu_lto_v1 symbol.

libgcc/ChangeLog:

2019-07-15  Martin Liska  <mliska@suse.cz>

	* config/pa/stublib.c: Remove stub symbol __gnu_lto_v1.
	* config/pa/t-stublib: Likewise.

libiberty/ChangeLog:

2019-07-15  Martin Liska  <mliska@suse.cz>

	* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
	Do not search for gnu_lto_v1, but search for first '\0'.
---
 gcc/config/avr/avr.c          |  2 +-
 gcc/toplev.c                  | 21 ---------------------
 libgcc/config/pa/stublib.c    |  4 ----
 libgcc/config/pa/t-stublib    |  6 +-----
 libiberty/simple-object-elf.c | 23 ++++++++---------------
 5 files changed, 10 insertions(+), 46 deletions(-)

Comments

Jeff Law July 21, 2019, 8:05 p.m. UTC | #1
On 7/15/19 7:30 AM, Martin Liška wrote:
> Hi.
> 
> The patch is about removal of the emission of __gnu_lto_v1.
> The symbol should not be needed any longer for GCC driver.
> 
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
> 
> Ready to be installed?
> Thanks,
> Martin
> 
> gcc/ChangeLog:
> 
> 2019-07-15  Martin Liska  <mliska@suse.cz>
> 
> 	* config/avr/avr.c (avr_asm_output_aligned_decl_common): Update
> 	comment.
> 	* toplev.c (compile_file): Do not emit __gnu_lto_v1 symbol.
> 
> libgcc/ChangeLog:
> 
> 2019-07-15  Martin Liska  <mliska@suse.cz>
> 
> 	* config/pa/stublib.c: Remove stub symbol __gnu_lto_v1.
> 	* config/pa/t-stublib: Likewise.
> 
> libiberty/ChangeLog:
> 
> 2019-07-15  Martin Liska  <mliska@suse.cz>
> 
> 	* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
> 	Do not search for gnu_lto_v1, but search for first '\0'.
OK.
jeff

Patch
diff mbox series

diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c
index b97faafdc3b..760e9371a01 100644
--- a/gcc/config/avr/avr.c
+++ b/gcc/config/avr/avr.c
@@ -10163,7 +10163,7 @@  avr_asm_output_aligned_decl_common (FILE * stream,
       return;
     }
 
-  /* __gnu_lto_v1 etc. are just markers for the linker injected by toplev.c.
+  /* __gnu_lto_slim is just a marker for the linker injected by toplev.c.
      There is no need to trigger __do_clear_bss code for them.  */
 
   if (!STR_PREFIX_P (name, "__gnu_lto"))
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 2567fe2e697..56ef63e5adb 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -543,27 +543,6 @@  compile_file (void)
       process_pending_assemble_externals ();
    }
 
-  /* Emit LTO marker if LTO info has been previously emitted.  This is
-     used by collect2 to determine whether an object file contains IL.
-     We used to emit an undefined reference here, but this produces
-     link errors if an object file with IL is stored into a shared
-     library without invoking lto1.  */
-  if (flag_generate_lto || flag_generate_offload)
-    {
-#if defined ASM_OUTPUT_ALIGNED_DECL_COMMON
-      ASM_OUTPUT_ALIGNED_DECL_COMMON (asm_out_file, NULL_TREE,
-				      "__gnu_lto_v1",
-				      HOST_WIDE_INT_1U, 8);
-#elif defined ASM_OUTPUT_ALIGNED_COMMON
-      ASM_OUTPUT_ALIGNED_COMMON (asm_out_file, "__gnu_lto_v1",
-				 HOST_WIDE_INT_1U, 8);
-#else
-      ASM_OUTPUT_COMMON (asm_out_file, "__gnu_lto_v1",
-			 HOST_WIDE_INT_1U,
-			 HOST_WIDE_INT_1U);
-#endif
-    }
-
   /* Let linker plugin know that this is a slim object and must be LTOed
      even when user did not ask for it.  */
   if (flag_generate_lto && !flag_fat_lto_objects)
diff --git a/libgcc/config/pa/stublib.c b/libgcc/config/pa/stublib.c
index b47afe15511..7e79dbfd6c9 100644
--- a/libgcc/config/pa/stublib.c
+++ b/libgcc/config/pa/stublib.c
@@ -115,7 +115,3 @@  pthread_once (void)
   return 0;
 }
 #endif
-
-#ifdef L_gnu_lto_v1
-char gnu_lto_v1;
-#endif
diff --git a/libgcc/config/pa/t-stublib b/libgcc/config/pa/t-stublib
index 0a6223d952e..8004c1e46a7 100644
--- a/libgcc/config/pa/t-stublib
+++ b/libgcc/config/pa/t-stublib
@@ -3,8 +3,7 @@  LIBGCCSTUB_OBJS = rfi-stub.o dfi-stub.o ritm-stub.o ditm-stub.o \
 	pthread_default_stacksize_np-stub.o \
 	pthread_mutex_lock-stub.o \
 	pthread_mutex_unlock-stub.o \
-	pthread_once-stub.o \
-	gnu_lto_v1-stub.o
+	pthread_once-stub.o
 
 rfi-stub.o: $(srcdir)/config/pa/stublib.c
 	$(gcc_compile) -c -O2 -DL_register_frame_info $<
@@ -36,9 +35,6 @@  pthread_mutex_unlock-stub.o: $(srcdir)/config/pa/stublib.c
 pthread_once-stub.o: $(srcdir)/config/pa/stublib.c
 	$(gcc_compile) -c -O2 -DL_pthread_once $<
 
-gnu_lto_v1-stub.o: $(srcdir)/config/pa/stublib.c
-	$(gcc_compile) -c -O2 -DL_gnu_lto_v1 $<
-
 libgcc_stub.a: $(LIBGCCSTUB_OBJS)
 	-rm -rf $@
 	$(AR) rc $@ $(LIBGCCSTUB_OBJS)
diff --git a/libiberty/simple-object-elf.c b/libiberty/simple-object-elf.c
index 22c9ae7ed2d..502388991a0 100644
--- a/libiberty/simple-object-elf.c
+++ b/libiberty/simple-object-elf.c
@@ -1358,9 +1358,8 @@  simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
 	  return errmsg;
 	}
 
-      /* If we are processing .symtab purge __gnu_lto_v1 and
-	 __gnu_lto_slim symbols from it and any symbols in discarded
-	 sections.  */
+      /* If we are processing .symtab purge __gnu_lto_slim symbol
+	 from it and any symbols in discarded sections.  */
       if (sh_type == SHT_SYMTAB)
 	{
 	  unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
@@ -1380,14 +1379,9 @@  simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
 				       sobj->offset + stroff,
 				       (unsigned char *)strings,
 				       strsz, &errmsg, err);
-	  /* Find gnu_lto_ in strings.  */
-	  while ((gnu_lto = (char *) memchr (gnu_lto, 'g',
-					     strings + strsz - gnu_lto)))
-	    if (strncmp (gnu_lto, "gnu_lto_v1",
-			 strings + strsz - gnu_lto) == 0)
-	      break;
-	    else
-	      gnu_lto++;
+	  /* Find first '\0' in strings.  */
+	  gnu_lto = (char *) memchr (gnu_lto, '\0',
+				     strings + strsz - gnu_lto + 1);
 	  /* Read the section index table if present.  */
 	  if (symtab_indices_shndx[i - 1] != 0)
 	    {
@@ -1461,10 +1455,9 @@  simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
 			 undefined and sharing the gnu_lto_ name.  */
 		      bind = STB_WEAK;
 		      other = STV_HIDDEN;
-		      if (gnu_lto)
-			ELF_SET_FIELD (type_functions, ei_class, Sym,
-				       ent, st_name, Elf_Word,
-				       gnu_lto - strings);
+		      ELF_SET_FIELD (type_functions, ei_class, Sym,
+				     ent, st_name, Elf_Word,
+				     gnu_lto - strings);
 		      ELF_SET_FIELD (type_functions, ei_class, Sym,
 				     ent, st_shndx, Elf_Half, SHN_UNDEF);
 		    }