From cc8547a776d53c324e8edc19a143a1ac75e7ca0a Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@linux.intel.com>
Date: Tue, 27 Sep 2011 14:36:48 +0000
Subject: [PATCH] invoke.texi (ffat-lto-objects): Document.
* doc/invoke.texi (ffat-lto-objects): Document.
* toplev.c (compile_file): Do not output assembly when doing slim lto;
Output __gnu_slim_lto when doing slim lto.
* cgraphunit.c (ipa_passes): Do only analysis when producing slim lto.
(cgraph_optimize): Return early when doing slim lto.
* opts.c (finish_options): Complain about lack of linker plugin
when doing slim lto.
* common.opt (ffat-lto-objects): New.
Co-Authored-By: Jan Hubicka <jh@suse.cz>
From-SVN: r179271
---
gcc/ChangeLog | 12 ++++++++
gcc/cgraphunit.c | 7 +++--
gcc/common.opt | 4 +++
gcc/doc/invoke.texi | 20 +++++++++++--
gcc/opts.c | 4 ++-
gcc/toplev.c | 70 +++++++++++++++++++++++++++++----------------
6 files changed, 87 insertions(+), 30 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 760713f288fe..eda5b975669b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2011-09-27 Andi Kleen <ak@linux.intel.com>
+ Jan Hubicka <jh@suse.cz>
+
+ * doc/invoke.texi (ffat-lto-objects): Document.
+ * toplev.c (compile_file): Do not output assembly when doing slim lto;
+ Output __gnu_slim_lto when doing slim lto.
+ * cgraphunit.c (ipa_passes): Do only analysis when producing slim lto.
+ (cgraph_optimize): Return early when doing slim lto.
+ * opts.c (finish_options): Complain about lack of linker plugin
+ when doing slim lto.
+ * common.opt (ffat-lto-objects): New.
+
2011-09-27 Richard Sandiford <richard.sandiford@linaro.org>
* ipa-inline-analysis.c (predicate_probability): Avoid comparison
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 2dedcc5c31a2..999b23823337 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -2042,7 +2042,7 @@ ipa_passes (void)
if (flag_generate_lto)
targetm.asm_out.lto_end ();
- if (!flag_ltrans)
+ if (!flag_ltrans && (in_lto_p || !flag_lto || flag_fat_lto_objects))
execute_ipa_pass_list (all_regular_ipa_passes);
invoke_plugin_callbacks (PLUGIN_ALL_IPA_PASSES_END, NULL);
@@ -2080,8 +2080,9 @@ cgraph_optimize (void)
if (!seen_error ())
ipa_passes ();
- /* Do nothing else if any IPA pass found errors. */
- if (seen_error ())
+ /* Do nothing else if any IPA pass found errors or if we are just streaming LTO. */
+ if (seen_error ()
+ || (!in_lto_p && flag_lto && !flag_fat_lto_objects))
{
timevar_pop (TV_CGRAPHOPT);
return;
diff --git a/gcc/common.opt b/gcc/common.opt
index ba3e254dd143..f237f76956ec 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1087,6 +1087,10 @@ Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
ffast-math
Common
+ffat-lto-objects
+Common Var(flag_fat_lto_objects) Init(1)
+Output lto objects containing both the intermediate language and binary output.
+
ffinite-math-only
Common Report Var(flag_finite_math_only) Optimization SetByCombined
Assume no NaNs or infinities are generated
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 1f04612c7aa9..9df741439f40 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -355,8 +355,8 @@ Objective-C and Objective-C++ Dialects}.
-fcx-limited-range @gol
-fdata-sections -fdce -fdce -fdelayed-branch @gol
-fdelete-null-pointer-checks -fdse -fdevirtualize -fdse @gol
--fearly-inlining -fipa-sra -fexpensive-optimizations -ffast-math @gol
--ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
+-fearly-inlining -fipa-sra -fexpensive-optimizations -ffat-lto-objects @gol
+-ffast-math -ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
-fforward-propagate -ffp-contract=@var{style} -ffunction-sections @gol
-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm -fgraphite-identity @gol
-fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol
@@ -7891,6 +7891,22 @@ use it.
Enabled by default when LTO support in GCC is enabled and GCC was compiled
with a linker supporting plugins (GNU ld 2.21 or newer or gold).
+@item -ffat-lto-objects
+@opindex ffat-lto-objects
+Fat LTO objects are object files that contain both the intermediate language
+and the object code. This makes them useable for both LTO linking and normal
+linking. This option makes effect only with @option{-flto} and is ignored
+at linktime.
+
+@option{-fno-fat-lto-objects} improves compilation time over plain LTO, but
+requires the complete toolchain to be aware of LTO. It requires a linker with
+linker plugin support for basic functionality. Additionally, nm, ar and ranlib
+need to support linker plugins to allow a full-featured build environment
+(capable of building static libraries etc).
+
+The default is @option{-ffat-lto-objects} but this default is intended to
+change in future releases when linker plugin enabled environments become more
+common.
@item -fcompare-elim
@opindex fcompare-elim
After register allocation and post-register allocation instruction splitting,
diff --git a/gcc/opts.c b/gcc/opts.c
index 5d5bcb960285..acf77895c8a1 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -779,7 +779,9 @@ finish_options (struct gcc_options *opts, struct gcc_options *opts_set,
#else
error_at (loc, "LTO support has not been enabled in this configuration");
#endif
- }
+ if (!opts->x_flag_fat_lto_objects && !HAVE_LTO_PLUGIN)
+ error_at (loc, "-fno-fat-lto-objects are supported only with linker plugin.");
+}
if ((opts->x_flag_lto_partition_balanced != 0) + (opts->x_flag_lto_partition_1to1 != 0)
+ (opts->x_flag_lto_partition_none != 0) >= 1)
{
diff --git a/gcc/toplev.c b/gcc/toplev.c
index de0a58a67731..3688c093a3f2 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -569,40 +569,45 @@ compile_file (void)
return;
}
- varpool_assemble_pending_decls ();
- finish_aliases_2 ();
+ /* Compilation unit is finalized. When producing non-fat LTO object, we are
+ basically finished. */
+ if (in_lto_p || !flag_lto || flag_fat_lto_objects)
+ {
+ varpool_assemble_pending_decls ();
+ finish_aliases_2 ();
- /* Likewise for mudflap static object registrations. */
- if (flag_mudflap)
- mudflap_finish_file ();
+ /* Likewise for mudflap static object registrations. */
+ if (flag_mudflap)
+ mudflap_finish_file ();
- output_shared_constant_pool ();
- output_object_blocks ();
+ output_shared_constant_pool ();
+ output_object_blocks ();
- /* Write out any pending weak symbol declarations. */
- weak_finish ();
+ /* Write out any pending weak symbol declarations. */
+ weak_finish ();
- /* This must be at the end before unwind and debug info.
- Some target ports emit PIC setup thunks here. */
- targetm.asm_out.code_end ();
+ /* This must be at the end before unwind and debug info.
+ Some target ports emit PIC setup thunks here. */
+ targetm.asm_out.code_end ();
- /* Do dbx symbols. */
- timevar_push (TV_SYMOUT);
+ /* Do dbx symbols. */
+ timevar_push (TV_SYMOUT);
-#if defined DWARF2_DEBUGGING_INFO || defined DWARF2_UNWIND_INFO
- if (dwarf2out_do_frame ())
- dwarf2out_frame_finish ();
-#endif
+ #if defined DWARF2_DEBUGGING_INFO || defined DWARF2_UNWIND_INFO
+ if (dwarf2out_do_frame ())
+ dwarf2out_frame_finish ();
+ #endif
- (*debug_hooks->finish) (main_input_filename);
- timevar_pop (TV_SYMOUT);
+ (*debug_hooks->finish) (main_input_filename);
+ timevar_pop (TV_SYMOUT);
- /* Output some stuff at end of file if nec. */
+ /* Output some stuff at end of file if nec. */
- dw2_output_indirect_constants ();
+ dw2_output_indirect_constants ();
- /* Flush any pending external directives. */
- process_pending_assemble_externals ();
+ /* Flush any pending external directives. */
+ 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.
@@ -623,6 +628,23 @@ compile_file (void)
(unsigned HOST_WIDE_INT) 1,
(unsigned HOST_WIDE_INT) 1);
#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_fat_lto_objects)
+ {
+#if defined ASM_OUTPUT_ALIGNED_DECL_COMMON
+ ASM_OUTPUT_ALIGNED_DECL_COMMON (asm_out_file, NULL_TREE,
+ "__gnu_slim_lto",
+ (unsigned HOST_WIDE_INT) 1, 8);
+#elif defined ASM_OUTPUT_ALIGNED_COMMON
+ ASM_OUTPUT_ALIGNED_COMMON (asm_out_file, "__gnu_slim_lto",
+ (unsigned HOST_WIDE_INT) 1, 8);
+#else
+ ASM_OUTPUT_COMMON (asm_out_file, "__gnu_slim_lto",
+ (unsigned HOST_WIDE_INT) 1,
+ (unsigned HOST_WIDE_INT) 1);
+#endif
+ }
}
/* Attach a special .ident directive to the end of the file to identify
--
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