On 5/2/22 10:51, Richard Biener wrote:
> On Mon, May 2, 2022 at 10:19 AM Martin Liška <mli...@suse.cz> wrote:
>>
>> On 5/2/22 10:09, Richard Biener wrote:
>>> On Mon, May 2, 2022 at 9:52 AM Martin Liška <mli...@suse.cz> wrote:
>>>>
>>>> Hi.
>>>>
>>>> This in a new plug-in function that helps identifying compiler
>>>> by a linker. Will be used in mold linker.
>>>>
>>>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>>>>
>>>> Ready to be installed?
>>>
>>> It looks a bit backward to query the compiler (and even more so to
>>> have a fixed set) from the linker. What is this going to be used for?
>>
>> It's going to be used by mold, there are small behavior divergence
>> in between LLVM and GCC, where one compiler closes provided file descriptors:
>> https://github.com/rui314/mold/blob/a15f3875269b575d024725590ae3ef87b611b8d8/elf/lto.cc#L545-L550
>
> But that then seems to be a defect in the plugin API specification (or
> one of the two implementations). Instead of adding a new API entry
> that defect should be fixed - both require changes in the actual plugin
> specification.
Well, the question is if it was specified somewhere or not. Plus there are
released
versions of both compilers and plug-ins, so it's not easily fixable :/
Martin
>
> Richard.
>
>>> If then this should probably receive a unformatted string the linker
>>> has to decipher itself like "gcc (SUSE Linux) 7.5.0" or something
>>> (what we produce with gcc --version), and clang would produce
>>> "clang version 11.0.1" or so?
>>
>> Well, it brings its own set of problems such string parsing. Note that the
>> plugin API
>> currently provides something like:
>>
>> /* The version of gold being used, or -1 if not gold. The number is
>> MAJOR * 100 + MINOR. */
>> static int gold_version = -1;
>>
>> So my suggestion is quite aligned with that.
>>
>> Martin
>>
>>>
>>> Richard.
>>>
>>>> Thanks,
>>>> Martin
>>>>
>>>> include/ChangeLog:
>>>>
>>>> * plugin-api.h (enum ld_plugin_compiler): New enum.
>>>> (enum ld_plugin_version): New typedef.
>>>> (struct ld_plugin_tv): Add new field.
>>>>
>>>> lto-plugin/ChangeLog:
>>>>
>>>> * lto-plugin.c (onload): Call ld_plugin_version.
>>>> ---
>>>> include/plugin-api.h | 18 +++++++++++++++++-
>>>> lto-plugin/lto-plugin.c | 4 ++++
>>>> 2 files changed, 21 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/include/plugin-api.h b/include/plugin-api.h
>>>> index 4e12c0320d6..4d0989028cc 100644
>>>> --- a/include/plugin-api.h
>>>> +++ b/include/plugin-api.h
>>>> @@ -211,6 +211,13 @@ enum ld_plugin_symbol_section_kind
>>>> LDSSK_BSS
>>>> };
>>>>
>>>> +enum ld_plugin_compiler
>>>> +{
>>>> + LDPC_UNKNOWN,
>>>> + LDPC_GCC,
>>>> + LDPC_LLVM
>>>> +};
>>>> +
>>>> /* How a symbol is resolved. */
>>>>
>>>> enum ld_plugin_symbol_resolution
>>>> @@ -475,6 +482,13 @@ enum ld_plugin_status
>>>> (*ld_plugin_get_wrap_symbols) (uint64_t *num_symbols,
>>>> const char ***wrap_symbol_list);
>>>>
>>>> +/* The linker's interface for registering the "plugin_version" handler.
>>>> + This handler is called directly after onload and provides compiler
>>>> + and its number version (MAJOR * 1000 + MINOR). */
>>>> +
>>>> +typedef
>>>> +void (*ld_plugin_version) (enum ld_plugin_compiler compiler, int version);
>>>> +
>>>> enum ld_plugin_level
>>>> {
>>>> LDPL_INFO,
>>>> @@ -520,7 +534,8 @@ enum ld_plugin_tag
>>>> LDPT_GET_INPUT_SECTION_SIZE = 30,
>>>> LDPT_REGISTER_NEW_INPUT_HOOK = 31,
>>>> LDPT_GET_WRAP_SYMBOLS = 32,
>>>> - LDPT_ADD_SYMBOLS_V2 = 33
>>>> + LDPT_ADD_SYMBOLS_V2 = 33,
>>>> + LDPT_PLUGIN_VERSION = 34,
>>>> };
>>>>
>>>> /* The plugin transfer vector. */
>>>> @@ -556,6 +571,7 @@ struct ld_plugin_tv
>>>> ld_plugin_get_input_section_size tv_get_input_section_size;
>>>> ld_plugin_register_new_input tv_register_new_input;
>>>> ld_plugin_get_wrap_symbols tv_get_wrap_symbols;
>>>> + ld_plugin_version tv_plugin_version;
>>>> } tv_u;
>>>> };
>>>>
>>>> diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
>>>> index 7a1c77812f6..698a0617ca7 100644
>>>> --- a/lto-plugin/lto-plugin.c
>>>> +++ b/lto-plugin/lto-plugin.c
>>>> @@ -69,6 +69,7 @@ along with this program; see the file COPYING3. If not
>>>> see
>>>> #include "../gcc/lto/common.h"
>>>> #include "simple-object.h"
>>>> #include "plugin-api.h"
>>>> +#include "ansidecl.h"
>>>>
>>>> /* We need to use I64 instead of ll width-specifier on native Windows.
>>>> The reason for this is that older MS-runtimes don't support the ll. */
>>>> @@ -1466,6 +1467,9 @@ onload (struct ld_plugin_tv *tv)
>>>> /* We only use this to make user-friendly temp file names. */
>>>> link_output_name = p->tv_u.tv_string;
>>>> break;
>>>> + case LDPT_PLUGIN_VERSION:
>>>> + p->tv_u.tv_plugin_version (LDPC_GCC, GCC_VERSION);
>>>> + break;
>>>> default:
>>>> break;
>>>> }
>>>> --
>>>> 2.36.0
>>>>
>>
