| Message ID | tencent_678E26B89931CE21728D777CFA825CDA1408@qq.com |
|---|---|
| State | New |
| Headers | show |
| Series | RISC-V: Add Function Multi-Versioning support | expand |
TARGET_HAS_FMV_TARGET_ATTRIBUTE should be a separate patch? it seems not related to TARGET_OPTION_FUNCTION_VERSIONS and TARGET_COMPARE_VERSION_PRIORITY? On Thu, Oct 24, 2024 at 3:13 PM Yangyu Chen <cyy@cyyself.name> wrote: > > This patch implements TARGET_COMPARE_VERSION_PRIORITY and > TARGET_OPTION_FUNCTION_VERSIONS for RISC-V. > > The TARGET_COMPARE_VERSION_PRIORITY is implemented to compare the > priority of two function versions based on the rules defined in the > RISC-V C-API Doc PR #85: > > https://github.com/riscv-non-isa/riscv-c-api-doc/pull/85/files#diff-79a93ca266139524b8b642e582ac20999357542001f1f4666fbb62b6fb7a5824R721 > > If multiple versions have equal priority, we select the function with > the most number of feature bits generated by > riscv_minimal_hwprobe_feature_bits. When it comes to the same number of > feature bits, we diff two versions and select the one with the least > significant bit set. Since a feature appears earlier in the feature_bits > might be more important to performance. > > The TARGET_OPTION_FUNCTION_VERSIONS is implemented to check whether the > two function versions are the same. This Implementation reuses the code > in TARGET_COMPARE_VERSION_PRIORITY and check it returns 0, which means > the equal priority. > > Co-Developed-by: Hank Chang <hank.chang@sifive.com> > > gcc/ChangeLog: > > * config/riscv/riscv-target-attr.cc > (riscv_target_attr_parser::update_settings): never free the > arch string. > * config/riscv/riscv.cc > (parse_features_for_version): New function. > (compare_fmv_features): New function. > (riscv_compare_version_priority): New function. > (riscv_common_function_versions): New function. > (TARGET_COMPARE_VERSION_PRIORITY): Implement it. > (TARGET_OPTION_FUNCTION_VERSIONS): Implement it. > * config/riscv/riscv.h (TARGET_HAS_FMV_TARGET_ATTRIBUTE): Define > it to 0 to use "target_version" for function versioning. > --- > gcc/config/riscv/riscv-target-attr.cc | 4 - > gcc/config/riscv/riscv.cc | 127 ++++++++++++++++++++++++++ > gcc/config/riscv/riscv.h | 2 + > 3 files changed, 129 insertions(+), 4 deletions(-) > > diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc > index 087fbae77b0..4c85ad60b72 100644 > --- a/gcc/config/riscv/riscv-target-attr.cc > +++ b/gcc/config/riscv/riscv-target-attr.cc > @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const > { > std::string local_arch = m_subset_list->to_string (true); > const char* local_arch_str = local_arch.c_str (); > - struct cl_target_option *default_opts > - = TREE_TARGET_OPTION (target_option_default_node); > - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) > - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); > opts->x_riscv_arch_string = xstrdup (local_arch_str); > > riscv_set_arch_by_subset_list (m_subset_list, opts); > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > index 3ac40234345..947864fc3a6 100644 > --- a/gcc/config/riscv/riscv.cc > +++ b/gcc/config/riscv/riscv.cc > @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) > return default_mode_for_floating_type (ti); > } > > +/* This parses the attribute arguments to target_version in DECL and modifies > + the feature mask and priority required to select those targets. */ > +static void > +parse_features_for_version (tree decl, > + struct riscv_feature_bits &res, > + int &priority) > +{ > + tree version_attr = lookup_attribute ("target_version", > + DECL_ATTRIBUTES (decl)); > + if (version_attr == NULL_TREE) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + > + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE > + (version_attr))); > + gcc_assert (version_string != NULL); > + if (strcmp (version_string, "default") == 0) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + struct cl_target_option cur_target; > + cl_target_option_save (&cur_target, &global_options, > + &global_options_set); > + /* Always set to default option before parsing "arch=+..." */ > + struct cl_target_option *default_opts > + = TREE_TARGET_OPTION (target_option_default_node); > + cl_target_option_restore (&global_options, &global_options_set, > + default_opts); > + > + riscv_process_target_attr (version_string, > + DECL_SOURCE_LOCATION (decl)); > + > + priority = global_options.x_riscv_fmv_priority; > + const char *arch_string = global_options.x_riscv_arch_string; > + bool parse_res > + = riscv_minimal_hwprobe_feature_bits (arch_string, &res, > + DECL_SOURCE_LOCATION (decl)); > + gcc_assert (parse_res); > + > + if (arch_string != default_opts->x_riscv_arch_string) > + free (CONST_CAST (void *, (const void *) arch_string)); > + > + cl_target_option_restore (&global_options, &global_options_set, > + &cur_target); > +} > + > +/* Compare priorities of two feature masks. Return: > + 1: mask1 is higher priority > + -1: mask2 is higher priority > + 0: masks are equal. > + Since riscv_feature_bits has total 128 bits to be used as mask, when counting > + the total 1s in the mask, the 1s in group1 needs to multiply a weight. */ > +static int > +compare_fmv_features (const struct riscv_feature_bits &mask1, > + const struct riscv_feature_bits &mask2, > + int prio1, int prio2) > +{ > + unsigned length1 = mask1.length, length2 = mask2.length; > + /* 1. Compare length, for length == 0 means default version, which should be > + the lowest priority). */ > + if (length1 != length2) > + return length1 > length2 ? 1 : -1; > + /* 2. Compare the priority. */ > + if (prio1 != prio2) > + return prio1 > prio2 ? 1 : -1; > + /* 3. Compare the total number of 1s in the mask. */ > + unsigned pop1 = 0, pop2 = 0; > + for (unsigned i = 0; i < length1; i++) > + { > + pop1 += __builtin_popcountll (mask1.features[i]); > + pop2 += __builtin_popcountll (mask2.features[i]); > + } > + if (pop1 != pop2) > + return pop1 > pop2 ? 1 : -1; > + /* 4. Compare the mask bit by bit order. */ > + for (unsigned i = 0; i < length1; i++) > + { > + unsigned long long xor_mask = mask1.features[i] ^ mask2.features[i]; > + if (xor_mask == 0) > + continue; > + return TEST_BIT (mask1.features[i], __builtin_ctzll (xor_mask)) ? 1 : -1; > + } > + /* 5. If all bits are equal, return 0. */ > + return 0; > +} > + > +/* Compare priorities of two version decls. Return: > + 1: mask1 is higher priority > + -1: mask2 is higher priority > + 0: masks are equal. */ > +int > +riscv_compare_version_priority (tree decl1, tree decl2) > +{ > + struct riscv_feature_bits mask1, mask2; > + int prio1, prio2; > + > + parse_features_for_version (decl1, mask1, prio1); > + parse_features_for_version (decl2, mask2, prio2); > + > + return compare_fmv_features (mask1, mask2, prio1, prio2); > +} > + > +/* This function returns true if FN1 and FN2 are versions of the same function, > + that is, the target_version attributes of the function decls are different. > + This assumes that FN1 and FN2 have the same signature. */ > + > +bool > +riscv_common_function_versions (tree fn1, tree fn2) > +{ > + if (TREE_CODE (fn1) != FUNCTION_DECL > + || TREE_CODE (fn2) != FUNCTION_DECL) > + return false; > + > + return riscv_compare_version_priority (fn1, fn2) != 0; > +} > + > /* On riscv we have an ABI defined safe buffer. This constant is used to > determining the probe offset for alloca. */ > > @@ -12948,6 +13069,12 @@ riscv_stack_clash_protection_alloca_probe_range (void) > #undef TARGET_C_MODE_FOR_FLOATING_TYPE > #define TARGET_C_MODE_FOR_FLOATING_TYPE riscv_c_mode_for_floating_type > > +#undef TARGET_COMPARE_VERSION_PRIORITY > +#define TARGET_COMPARE_VERSION_PRIORITY riscv_compare_version_priority > + > +#undef TARGET_OPTION_FUNCTION_VERSIONS > +#define TARGET_OPTION_FUNCTION_VERSIONS riscv_common_function_versions > + > struct gcc_target targetm = TARGET_INITIALIZER; > > #include "gt-riscv.h" > diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h > index 2ff9c1024f3..8a8b08b6b51 100644 > --- a/gcc/config/riscv/riscv.h > +++ b/gcc/config/riscv/riscv.h > @@ -1303,4 +1303,6 @@ extern void riscv_remove_unneeded_save_restore_calls (void); > the target attribute. */ > #define TARGET_CLONES_ATTR_SEPARATOR '#' > > +#define TARGET_HAS_FMV_TARGET_ATTRIBUTE 0 > + > #endif /* ! GCC_RISCV_H */ > -- > 2.45.2 >
> diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc > index 087fbae77b0..4c85ad60b72 100644 > --- a/gcc/config/riscv/riscv-target-attr.cc > +++ b/gcc/config/riscv/riscv-target-attr.cc > @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const > { > std::string local_arch = m_subset_list->to_string (true); > const char* local_arch_str = local_arch.c_str (); > - struct cl_target_option *default_opts > - = TREE_TARGET_OPTION (target_option_default_node); > - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) > - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); Could you give a little more context why you decide to remove those logics? > opts->x_riscv_arch_string = xstrdup (local_arch_str); > > riscv_set_arch_by_subset_list (m_subset_list, opts); > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > index 3ac40234345..947864fc3a6 100644 > --- a/gcc/config/riscv/riscv.cc > +++ b/gcc/config/riscv/riscv.cc > @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) > return default_mode_for_floating_type (ti); > } > > +/* This parses the attribute arguments to target_version in DECL and modifies > + the feature mask and priority required to select those targets. */ > +static void > +parse_features_for_version (tree decl, > + struct riscv_feature_bits &res, > + int &priority) > +{ > + tree version_attr = lookup_attribute ("target_version", > + DECL_ATTRIBUTES (decl)); > + if (version_attr == NULL_TREE) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + > + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE > + (version_attr))); > + gcc_assert (version_string != NULL); > + if (strcmp (version_string, "default") == 0) > + { > + res.length = 0; > + priority = 0; > + return; > + } > + struct cl_target_option cur_target; > + cl_target_option_save (&cur_target, &global_options, > + &global_options_set); > + /* Always set to default option before parsing "arch=+..." */ > + struct cl_target_option *default_opts > + = TREE_TARGET_OPTION (target_option_default_node); > + cl_target_option_restore (&global_options, &global_options_set, > + default_opts); > + > + riscv_process_target_attr (version_string, > + DECL_SOURCE_LOCATION (decl)); Is it possible to just use DECL_FUNCTION_SPECIFIC_TARGET (decl) here rather than parse and apply that globally?
> On Oct 31, 2024, at 18:14, Kito Cheng <kito.cheng@gmail.com> wrote: > >> diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc >> index 087fbae77b0..4c85ad60b72 100644 >> --- a/gcc/config/riscv/riscv-target-attr.cc >> +++ b/gcc/config/riscv/riscv-target-attr.cc >> @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const >> { >> std::string local_arch = m_subset_list->to_string (true); >> const char* local_arch_str = local_arch.c_str (); >> - struct cl_target_option *default_opts >> - = TREE_TARGET_OPTION (target_option_default_node); >> - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) >> - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); > > Could you give a little more context why you decide to remove those logics? > That's because when we have target_version features, the riscv_arch_string may need to be stored in the DECL_FUNCTION_SPECIFIC_TARGET. If we free the arch string, it may have use-after-free bugs. I came across this bug even without ASAN. I know that if we didn't free it, it might cause a memory leak. But for GCC, it’s OK, I think. It's also complex to add something like std::shared_ptr or std::string to the global options. If this explanation is OK, I will add a comment about this in this source file. >> opts->x_riscv_arch_string = xstrdup (local_arch_str); >> >> riscv_set_arch_by_subset_list (m_subset_list, opts); >> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc >> index 3ac40234345..947864fc3a6 100644 >> --- a/gcc/config/riscv/riscv.cc >> +++ b/gcc/config/riscv/riscv.cc >> @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) >> return default_mode_for_floating_type (ti); >> } >> >> +/* This parses the attribute arguments to target_version in DECL and modifies >> + the feature mask and priority required to select those targets. */ >> +static void >> +parse_features_for_version (tree decl, >> + struct riscv_feature_bits &res, >> + int &priority) >> +{ >> + tree version_attr = lookup_attribute ("target_version", >> + DECL_ATTRIBUTES (decl)); >> + if (version_attr == NULL_TREE) >> + { >> + res.length = 0; >> + priority = 0; >> + return; >> + } >> + >> + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE >> + (version_attr))); >> + gcc_assert (version_string != NULL); >> + if (strcmp (version_string, "default") == 0) >> + { >> + res.length = 0; >> + priority = 0; >> + return; >> + } >> + struct cl_target_option cur_target; >> + cl_target_option_save (&cur_target, &global_options, >> + &global_options_set); >> + /* Always set to default option before parsing "arch=+..." */ >> + struct cl_target_option *default_opts >> + = TREE_TARGET_OPTION (target_option_default_node); >> + cl_target_option_restore (&global_options, &global_options_set, >> + default_opts); >> + >> + riscv_process_target_attr (version_string, >> + DECL_SOURCE_LOCATION (decl)); > > Is it possible to just use DECL_FUNCTION_SPECIFIC_TARGET (decl) here > rather than parse and apply that globally? For DECL_FUNCTION_SPECIFIC_TARGET, the answer is no. That's because the function may not be versioned when calling from TARGET_OPTION_FUNCTION_VERSIONS. You can check this by applying this assert and running the test in the final patch to see the stack dump: ```diff diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index 20c6bf4f2e4..1b39c33c518 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -12692,6 +12692,7 @@ parse_features_for_version (tree decl, struct riscv_feature_bits &res, int &priority) { + gcc_assert (decl != NULL && DECL_FUNCTION_VERSIONED (decl)); tree version_attr = lookup_attribute ("target_version", DECL_ATTRIBUTES (decl)); if (version_attr == NULL_TREE) ``` ```console test2.cpp:5:10: internal compiler error: in parse_features_for_version, at config/riscv/riscv.cc:12695 5 | void foo() {} | ^ 0x30dd120 internal_error(char const*, ...) ../.././gcc/gcc/diagnostic-global-context.cc:518 0xd2ca07 fancy_abort(char const*, int, char const*) ../.././gcc/gcc/diagnostic.cc:1693 0xc5713d parse_features_for_version ../.././gcc/gcc/config/riscv/riscv.cc:12695 0x1a9b51f riscv_compare_version_priority(tree_node*, tree_node*) ../.././gcc/gcc/config/riscv/riscv.cc:12790 0x1a9b69a riscv_common_function_versions(tree_node*, tree_node*) ../.././gcc/gcc/config/riscv/riscv.cc:12808 0x1a9b69a riscv_common_function_versions(tree_node*, tree_node*) ../.././gcc/gcc/config/riscv/riscv.cc:12801 0xdf1a9e decls_match(tree_node*, tree_node*, bool) ../.././gcc/gcc/cp/decl.cc:1213 0xe1d5bd find_last_decl ../.././gcc/gcc/cp/decl2.cc:1752 0xe1d5bd cplus_decl_attributes(tree_node**, tree_node*, int) ../.././gcc/gcc/cp/decl2.cc:1888 <http://decl2.cc:1888/> ```
On Thu, Oct 31, 2024 at 6:59 PM Yangyu Chen <cyy@cyyself.name> wrote: > > > > > On Oct 31, 2024, at 18:14, Kito Cheng <kito.cheng@gmail.com> wrote: > > > >> diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc > >> index 087fbae77b0..4c85ad60b72 100644 > >> --- a/gcc/config/riscv/riscv-target-attr.cc > >> +++ b/gcc/config/riscv/riscv-target-attr.cc > >> @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const > >> { > >> std::string local_arch = m_subset_list->to_string (true); > >> const char* local_arch_str = local_arch.c_str (); > >> - struct cl_target_option *default_opts > >> - = TREE_TARGET_OPTION (target_option_default_node); > >> - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) > >> - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); > > > > Could you give a little more context why you decide to remove those logics? > > > > That's because when we have target_version features, the riscv_arch_string > may need to be stored in the DECL_FUNCTION_SPECIFIC_TARGET. If we > free the arch string, it may have use-after-free bugs. I came across > this bug even without ASAN. > > I know that if we didn't free it, it might cause a memory leak. But > for GCC, it’s OK, I think. It's also complex to add something like > std::shared_ptr or std::string to the global options. > > If this explanation is OK, I will add a comment about this in this > source file. Thanks for the explanation, then let's keep the original code and wrap it with `#if 0` and leave some comments there :) > > >> opts->x_riscv_arch_string = xstrdup (local_arch_str); > >> > >> riscv_set_arch_by_subset_list (m_subset_list, opts); > >> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > >> index 3ac40234345..947864fc3a6 100644 > >> --- a/gcc/config/riscv/riscv.cc > >> +++ b/gcc/config/riscv/riscv.cc > >> @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) > >> return default_mode_for_floating_type (ti); > >> } > >> > >> +/* This parses the attribute arguments to target_version in DECL and modifies > >> + the feature mask and priority required to select those targets. */ > >> +static void > >> +parse_features_for_version (tree decl, > >> + struct riscv_feature_bits &res, > >> + int &priority) > >> +{ > >> + tree version_attr = lookup_attribute ("target_version", > >> + DECL_ATTRIBUTES (decl)); > >> + if (version_attr == NULL_TREE) > >> + { > >> + res.length = 0; > >> + priority = 0; > >> + return; > >> + } > >> + > >> + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE > >> + (version_attr))); > >> + gcc_assert (version_string != NULL); > >> + if (strcmp (version_string, "default") == 0) > >> + { > >> + res.length = 0; > >> + priority = 0; > >> + return; > >> + } > >> + struct cl_target_option cur_target; > >> + cl_target_option_save (&cur_target, &global_options, > >> + &global_options_set); > >> + /* Always set to default option before parsing "arch=+..." */ > >> + struct cl_target_option *default_opts > >> + = TREE_TARGET_OPTION (target_option_default_node); > >> + cl_target_option_restore (&global_options, &global_options_set, > >> + default_opts); > >> + > >> + riscv_process_target_attr (version_string, > >> + DECL_SOURCE_LOCATION (decl)); > > > > Is it possible to just use DECL_FUNCTION_SPECIFIC_TARGET (decl) here > > rather than parse and apply that globally? > > For DECL_FUNCTION_SPECIFIC_TARGET, the answer is no. > > That's because the function may not be versioned when calling from > TARGET_OPTION_FUNCTION_VERSIONS. > > You can check this by applying this assert and running the test in > the final patch to see the stack dump: So sad, ok, let keep as it
On 10/31/24 21:26, Kito Cheng wrote: > On Thu, Oct 31, 2024 at 6:59 PM Yangyu Chen <cyy@cyyself.name> wrote: >>> On Oct 31, 2024, at 18:14, Kito Cheng <kito.cheng@gmail.com> wrote: >>> >>>> diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc >>>> index 087fbae77b0..4c85ad60b72 100644 >>>> --- a/gcc/config/riscv/riscv-target-attr.cc >>>> +++ b/gcc/config/riscv/riscv-target-attr.cc >>>> @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const >>>> { >>>> std::string local_arch = m_subset_list->to_string (true); >>>> const char* local_arch_str = local_arch.c_str (); >>>> - struct cl_target_option *default_opts >>>> - = TREE_TARGET_OPTION (target_option_default_node); >>>> - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) >>>> - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); >>> >>> Could you give a little more context why you decide to remove those logics? >>> >> >> That's because when we have target_version features, the riscv_arch_string >> may need to be stored in the DECL_FUNCTION_SPECIFIC_TARGET. If we >> free the arch string, it may have use-after-free bugs. I came across >> this bug even without ASAN. >> >> I know that if we didn't free it, it might cause a memory leak. But >> for GCC, it’s OK, I think. It's also complex to add something like >> std::shared_ptr or std::string to the global options. >> >> If this explanation is OK, I will add a comment about this in this >> source file. > > Thanks for the explanation, then let's keep the original code and wrap > it with `#if 0` and leave some comments there :) > Update: I found this use-after-free bug no longer happens after I restored default_opts to global_options in the function parse_features_for_version in this patch. These lines were just added when I was debugging this UAF bug. Since they are no longer needed, I will drop these lines in the next revision.
diff --git a/gcc/config/riscv/riscv-target-attr.cc b/gcc/config/riscv/riscv-target-attr.cc index 087fbae77b0..4c85ad60b72 100644 --- a/gcc/config/riscv/riscv-target-attr.cc +++ b/gcc/config/riscv/riscv-target-attr.cc @@ -239,10 +239,6 @@ riscv_target_attr_parser::update_settings (struct gcc_options *opts) const { std::string local_arch = m_subset_list->to_string (true); const char* local_arch_str = local_arch.c_str (); - struct cl_target_option *default_opts - = TREE_TARGET_OPTION (target_option_default_node); - if (opts->x_riscv_arch_string != default_opts->x_riscv_arch_string) - free (CONST_CAST (void *, (const void *) opts->x_riscv_arch_string)); opts->x_riscv_arch_string = xstrdup (local_arch_str); riscv_set_arch_by_subset_list (m_subset_list, opts); diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index 3ac40234345..947864fc3a6 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -12574,6 +12574,127 @@ riscv_c_mode_for_floating_type (enum tree_index ti) return default_mode_for_floating_type (ti); } +/* This parses the attribute arguments to target_version in DECL and modifies + the feature mask and priority required to select those targets. */ +static void +parse_features_for_version (tree decl, + struct riscv_feature_bits &res, + int &priority) +{ + tree version_attr = lookup_attribute ("target_version", + DECL_ATTRIBUTES (decl)); + if (version_attr == NULL_TREE) + { + res.length = 0; + priority = 0; + return; + } + + const char *version_string = TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE + (version_attr))); + gcc_assert (version_string != NULL); + if (strcmp (version_string, "default") == 0) + { + res.length = 0; + priority = 0; + return; + } + struct cl_target_option cur_target; + cl_target_option_save (&cur_target, &global_options, + &global_options_set); + /* Always set to default option before parsing "arch=+..." */ + struct cl_target_option *default_opts + = TREE_TARGET_OPTION (target_option_default_node); + cl_target_option_restore (&global_options, &global_options_set, + default_opts); + + riscv_process_target_attr (version_string, + DECL_SOURCE_LOCATION (decl)); + + priority = global_options.x_riscv_fmv_priority; + const char *arch_string = global_options.x_riscv_arch_string; + bool parse_res + = riscv_minimal_hwprobe_feature_bits (arch_string, &res, + DECL_SOURCE_LOCATION (decl)); + gcc_assert (parse_res); + + if (arch_string != default_opts->x_riscv_arch_string) + free (CONST_CAST (void *, (const void *) arch_string)); + + cl_target_option_restore (&global_options, &global_options_set, + &cur_target); +} + +/* Compare priorities of two feature masks. Return: + 1: mask1 is higher priority + -1: mask2 is higher priority + 0: masks are equal. + Since riscv_feature_bits has total 128 bits to be used as mask, when counting + the total 1s in the mask, the 1s in group1 needs to multiply a weight. */ +static int +compare_fmv_features (const struct riscv_feature_bits &mask1, + const struct riscv_feature_bits &mask2, + int prio1, int prio2) +{ + unsigned length1 = mask1.length, length2 = mask2.length; + /* 1. Compare length, for length == 0 means default version, which should be + the lowest priority). */ + if (length1 != length2) + return length1 > length2 ? 1 : -1; + /* 2. Compare the priority. */ + if (prio1 != prio2) + return prio1 > prio2 ? 1 : -1; + /* 3. Compare the total number of 1s in the mask. */ + unsigned pop1 = 0, pop2 = 0; + for (unsigned i = 0; i < length1; i++) + { + pop1 += __builtin_popcountll (mask1.features[i]); + pop2 += __builtin_popcountll (mask2.features[i]); + } + if (pop1 != pop2) + return pop1 > pop2 ? 1 : -1; + /* 4. Compare the mask bit by bit order. */ + for (unsigned i = 0; i < length1; i++) + { + unsigned long long xor_mask = mask1.features[i] ^ mask2.features[i]; + if (xor_mask == 0) + continue; + return TEST_BIT (mask1.features[i], __builtin_ctzll (xor_mask)) ? 1 : -1; + } + /* 5. If all bits are equal, return 0. */ + return 0; +} + +/* Compare priorities of two version decls. Return: + 1: mask1 is higher priority + -1: mask2 is higher priority + 0: masks are equal. */ +int +riscv_compare_version_priority (tree decl1, tree decl2) +{ + struct riscv_feature_bits mask1, mask2; + int prio1, prio2; + + parse_features_for_version (decl1, mask1, prio1); + parse_features_for_version (decl2, mask2, prio2); + + return compare_fmv_features (mask1, mask2, prio1, prio2); +} + +/* This function returns true if FN1 and FN2 are versions of the same function, + that is, the target_version attributes of the function decls are different. + This assumes that FN1 and FN2 have the same signature. */ + +bool +riscv_common_function_versions (tree fn1, tree fn2) +{ + if (TREE_CODE (fn1) != FUNCTION_DECL + || TREE_CODE (fn2) != FUNCTION_DECL) + return false; + + return riscv_compare_version_priority (fn1, fn2) != 0; +} + /* On riscv we have an ABI defined safe buffer. This constant is used to determining the probe offset for alloca. */ @@ -12948,6 +13069,12 @@ riscv_stack_clash_protection_alloca_probe_range (void) #undef TARGET_C_MODE_FOR_FLOATING_TYPE #define TARGET_C_MODE_FOR_FLOATING_TYPE riscv_c_mode_for_floating_type +#undef TARGET_COMPARE_VERSION_PRIORITY +#define TARGET_COMPARE_VERSION_PRIORITY riscv_compare_version_priority + +#undef TARGET_OPTION_FUNCTION_VERSIONS +#define TARGET_OPTION_FUNCTION_VERSIONS riscv_common_function_versions + struct gcc_target targetm = TARGET_INITIALIZER; #include "gt-riscv.h" diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h index 2ff9c1024f3..8a8b08b6b51 100644 --- a/gcc/config/riscv/riscv.h +++ b/gcc/config/riscv/riscv.h @@ -1303,4 +1303,6 @@ extern void riscv_remove_unneeded_save_restore_calls (void); the target attribute. */ #define TARGET_CLONES_ATTR_SEPARATOR '#' +#define TARGET_HAS_FMV_TARGET_ATTRIBUTE 0 + #endif /* ! GCC_RISCV_H */