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.
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
> >>
>
