On Mon, Nov 24, 2014 at 5:44 PM, Ilya Verbin <iver...@gmail.com> wrote:
> On 17 Nov 10:57, Richard Biener wrote:
>> On Fri, Nov 14, 2014 at 6:08 PM, Ilya Verbin <iver...@gmail.com> wrote:
>> > On 14 Nov 09:01, H.J. Lu wrote:
>> >> On Fri, Nov 14, 2014 at 8:51 AM, Ilya Verbin <iver...@gmail.com> wrote:
>> >> > On 14 Nov 08:46, H.J. Lu wrote:
>> >> >> What happens when -flto is used on command line? Will we
>> >> >> generate both LTO IR and offload IR?
>> >> >
>> >> > Right.
>> >> >
>> >> > I'm not sure whether we should make slim objects in case of LTO +
>> >> > offload IR...
>> >> >
>> >>
>> >> Isn't __gnu_lto_slim only applied to regular LTO IR? Should offload IR be
>> >> handled separately from regular LTO IR? It is odd to use
>> >> flag_fat_lto_objects
>> >> to control offload IR.
>> >
>> > It is handled separately, but it uses a common infrastructure with regular
>> > LTO
>> > for streaming, therefore compile_file automatically emits __gnu_lto_slim
>> > when
>> > there is at least one section with IR (flag_generate_lto is set). You
>> > propose
>> > to introduce a second flag like flag_fat_lto_objects to disable
>> > __gnu_lto_slim?
>>
>> Err... why is offloading not guarded with a new symbol like
>> __gnu_lto_offload?
>
> Well, it's possible to guard offload IR with a new symbol, using a patch like
> this (it is not fully regtested). But I don't like it... Maybe we could just
> change the meaning of "__gnu_lto_v1" from "object contains LTO IR" to "object
> contains any IR"? In collect2 both LTO and offload cases are handled
> identically. Is there other place where the symbol is used?
I don't think so (and even collect2.c should be changed to use simple-object
to identify LTO objects rather than ar...). But I think libtool uses
it as well.
In the patch adding flag_generate_offload sounds like a good solution,
I didn't like emitting fat LTO objects unconditionally just because we offload.
Richard.
> -- Ilya
>
>
> diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
> index c133a22..f09d79d 100644
> --- a/gcc/ada/gcc-interface/decl.c
> +++ b/gcc/ada/gcc-interface/decl.c
> @@ -1490,7 +1490,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree
> gnu_expr, int definition)
> && definition
> && debug_info_p
> && !optimize
> - && !flag_generate_lto)
> + && !flag_generate_lto
> + && !flag_generate_offload)
> {
> tree param = create_param_decl (gnu_entity_name, gnu_type, false);
> gnat_pushdecl (param, gnat_entity);
> diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
> index 2fd99a7..fed1a3e 100644
> --- a/gcc/cgraphunit.c
> +++ b/gcc/cgraphunit.c
> @@ -2075,7 +2075,7 @@ ipa_passes (void)
> }
>
> /* Some targets need to handle LTO assembler output specially. */
> - if (flag_generate_lto)
> + if (flag_generate_lto || flag_generate_offload)
> targetm.asm_out.lto_start ();
>
> if (!in_lto_p)
> @@ -2092,7 +2092,7 @@ ipa_passes (void)
> }
> }
>
> - if (flag_generate_lto)
> + if (flag_generate_lto || flag_generate_offload)
> targetm.asm_out.lto_end ();
>
> if (!flag_ltrans && (in_lto_p || !flag_lto || flag_fat_lto_objects))
> @@ -2176,10 +2176,10 @@ symbol_table::compile (void)
>
> /* Offloading requires LTO infrastructure. */
> if (!in_lto_p && g->have_offload)
> - flag_generate_lto = 1;
> + flag_generate_offload = 1;
>
> /* If LTO is enabled, initialize the streamer hooks needed by GIMPLE. */
> - if (flag_generate_lto)
> + if (flag_generate_lto || flag_generate_offload)
> lto_streamer_hooks_init ();
>
> /* Don't run the IPA passes if there was any error or sorry messages. */
> diff --git a/gcc/collect2.c b/gcc/collect2.c
> index 9c3a1c5..2dcebcd 100644
> --- a/gcc/collect2.c
> +++ b/gcc/collect2.c
> @@ -2392,12 +2392,16 @@ scan_prog_file (const char *prog_name, scanpass
> which_pass,
> if (found_lto)
> continue;
>
> - /* Look for the LTO info marker symbol, and add filename to
> + /* Look for the LTO or offload info marker symbol, and add
> filename to
> the LTO objects list if found. */
> for (p = buf; (ch = *p) != '\0' && ch != '\n'; p++)
> if (ch == ' ' && p[1] == '_' && p[2] == '_'
> - && (strncmp (p + (p[3] == '_' ? 2 : 1), "__gnu_lto_v1", 12)
> == 0)
> - && ISSPACE (p[p[3] == '_' ? 14 : 13]))
> + && (((strncmp (p + (p[3] == '_' ? 2 : 1),
> + "__gnu_lto_v1", 12) == 0)
> + && ISSPACE (p[p[3] == '_' ? 14 : 13]))
> + || ((strncmp (p + (p[3] == '_' ? 2 : 1),
> + "__gnu_offload_v1", 16) == 0)
> + && ISSPACE (p[p[3] == '_' ? 18 : 17]))))
> {
> add_lto_object (<o_objects, prog_name);
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 41c8d4e..11a5500 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -67,6 +67,10 @@ int *param_values
> Variable
> int flag_generate_lto
>
> +; Nonzero if we should write GIMPLE bytecode for offload compilation.
> +Variable
> +int flag_generate_offload
> +
> ; True to warn about any objects definitions whose size is larger
> ; than N bytes. Also want about function definitions whose returned
> ; values are larger than N bytes, where N is 'larger_than_size'.
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 3d50ac9..3e83213 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -24390,7 +24390,8 @@ dwarf2out_finish (const char *filename)
> /* When generating LTO bytecode we can not generate new assembler
> names at this point and all important decls got theirs via
> free-lang-data. */
> - if ((!flag_generate_lto || DECL_ASSEMBLER_NAME_SET_P (decl))
> + if (((!flag_generate_lto && !flag_generate_offload)
> + || DECL_ASSEMBLER_NAME_SET_P (decl))
> && DECL_ASSEMBLER_NAME (decl) != DECL_NAME (decl))
> {
> add_linkage_attr (node->die, decl);
> diff --git a/gcc/ipa-inline-analysis.c b/gcc/ipa-inline-analysis.c
> index 2f2993c..9d62722 100644
> --- a/gcc/ipa-inline-analysis.c
> +++ b/gcc/ipa-inline-analysis.c
> @@ -4031,7 +4031,7 @@ inline_generate_summary (void)
>
> /* When not optimizing, do not bother to analyze. Inlining is still done
> because edge redirection needs to happen there. */
> - if (!optimize && !flag_generate_lto && !flag_wpa)
> + if (!optimize && !flag_generate_lto && !flag_generate_offload && !flag_wpa)
> return;
>
> function_insertion_hook_holder =
> diff --git a/gcc/lto-streamer.c b/gcc/lto-streamer.c
> index e8347dc..af20330 100644
> --- a/gcc/lto-streamer.c
> +++ b/gcc/lto-streamer.c
> @@ -328,7 +328,7 @@ lto_streamer_init (void)
> bool
> gate_lto_out (void)
> {
> - return ((flag_generate_lto || in_lto_p)
> + return ((flag_generate_lto || flag_generate_offload || in_lto_p)
> /* Don't bother doing anything if the program has errors. */
> && !seen_error ());
> }
> diff --git a/gcc/passes.c b/gcc/passes.c
> index a3be0bb..74b40e5 100644
> --- a/gcc/passes.c
> +++ b/gcc/passes.c
> @@ -2466,7 +2466,7 @@ ipa_write_summaries (bool offload_lto_mode)
> struct cgraph_node *node;
> struct cgraph_node **order;
>
> - if (!flag_generate_lto || seen_error ())
> + if ((!flag_generate_lto && !flag_generate_offload) || seen_error ())
> return;
>
> select_what_to_stream (offload_lto_mode);
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index 6e6adfa..2d84b0a 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -672,6 +672,27 @@ compile_file (void)
> }
> }
>
> + /* Emit offload marker if offload 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_offload)
> + {
> +#if defined ASM_OUTPUT_ALIGNED_DECL_COMMON
> + ASM_OUTPUT_ALIGNED_DECL_COMMON (asm_out_file, NULL_TREE,
> + "__gnu_offload_v1",
> + (unsigned HOST_WIDE_INT) 1, 8);
> +#elif defined ASM_OUTPUT_ALIGNED_COMMON
> + ASM_OUTPUT_ALIGNED_COMMON (asm_out_file, "__gnu_offload_v1",
> + (unsigned HOST_WIDE_INT) 1, 8);
> +#else
> + ASM_OUTPUT_COMMON (asm_out_file, "__gnu_offload_v1",
> + (unsigned HOST_WIDE_INT) 1,
> + (unsigned HOST_WIDE_INT) 1);
> +#endif
> + }
> +
> /* Attach a special .ident directive to the end of the file to identify
> the version of GCC which compiled this code. The format of the .ident
> string is patterned after the ones produced by native SVR4 compilers.
> */
> diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
> index d4864ae..d4ebf52 100644
> --- a/gcc/tree-inline.c
> +++ b/gcc/tree-inline.c
> @@ -4383,7 +4383,8 @@ expand_call_inline (basic_block bb, gimple stmt,
> copy_body_data *id)
> || !optimize
> || cgraph_inline_failed_type (reason) == CIF_FINAL_ERROR)
> /* PR 20090218-1_0.c. Body can be provided by another module. */
> - && (reason != CIF_BODY_NOT_AVAILABLE || !flag_generate_lto))
> + && (reason != CIF_BODY_NOT_AVAILABLE
> + || (!flag_generate_lto && !flag_generate_offload)))
> {
> error ("inlining failed in call to always_inline %q+F: %s", fn,
> cgraph_inline_failed_string (reason));
> diff --git a/gcc/tree.c b/gcc/tree.c
> index 1d5e4f6..f6a6d04 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -5730,7 +5730,7 @@ free_lang_data (void)
>
> /* If we are the LTO frontend we have freed lang-specific data already. */
> if (in_lto_p
> - || !flag_generate_lto)
> + || (!flag_generate_lto && !flag_generate_offload))
> return 0;
>
> /* Allocate and assign alias sets to the standard integer types
