On Mon, May 2, 2022 at 10:51 AM Richard Biener
<richard.guent...@gmail.com> 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.
implementation of course.
Richard.
>
> 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
> > >>
> >
