From: Kito Cheng <kito.cheng@sifive.com>
To: gcc-patches@gcc.gnu.org, kito.cheng@gmail.com, jimw@sifive.com
Cc: Kito Cheng <kito.cheng@sifive.com>
Subject: [PATCH 2/2] RISC-V: Implement TARGET_COMPUTE_MULTILIB
Date: Wed, 21 Jul 2021 17:28:11 +0800 [thread overview]
Message-ID: <20210721092810.66070-3-kito.cheng@sifive.com> (raw)
In-Reply-To: <20210721092810.66070-1-kito.cheng@sifive.com>
Use TARGET_COMPUTE_MULTILIB to search the multi-lib reuse for riscv*-*-elf*,
according following rules:
1. Check ABI is same.
2. Check both has atomic extension or both don't have atomic extension.
- Because mix soft and hard atomic operation doesn't make sense and
won't work as expect.
3. Check current arch is superset of the target multi-lib arch.
- It might result slower performance or larger code size, but it
safe to run.
4. Pick most match multi-lib set if more than one multi-lib are pass
the above checking.
Example for how to select multi-lib:
We build code with -march=rv32imaf and -mabi=ilp32, and we have
following 5 multi-lib set:
1. rv32ia/ilp32
2. rv32ima/ilp32
3. rv32imf/ilp32
4. rv32imaf/ilp32f
5. rv32imafd/ilp32
The first and second multi-lib is safe to like, 3rd multi-lib can't
re-use becasue it don't have atomic extension, which is mismatch according
rule 2, and the 4th multi-lib can't re-use too due to the ABI mismatch,
the last multi-lib can't use since current arch is not superset of the
arch of multi-lib.
And emit error if not found suitable multi-lib set, the error message
only emit when link with standard libraries.
Example for when error will be emitted:
$ riscv64-unknown-elf-gcc -print-multi-lib
.;
rv32i/ilp32;@march=rv32i@mabi=ilp32
rv32im/ilp32;@march=rv32im@mabi=ilp32
rv32iac/ilp32;@march=rv32iac@mabi=ilp32
rv32imac/ilp32;@march=rv32imac@mabi=ilp32
rv32imafc/ilp32f;@march=rv32imafc@mabi=ilp32f
rv64imac/lp64;@march=rv64imac@mabi=lp64
// No actual linking, so no error emitted.
$ riscv64-unknown-elf-gcc -print-multi-directory -march=rv32ia -mabi=ilp32
.
// Link to default libc and libgcc, so check the multi-lib, and emit
// error because not found suitable multilib.
$ riscv64-unknown-elf-gcc -march=rv32ia -mabi=ilp32 ~/hello.c
riscv64-unknown-elf-gcc: fatal error: can't found suitable multilib set for '-march=rv32ia'/'-mabi=ilp32'
compilation terminated.
// No error emitted, because not link to stdlib.
$ riscv64-unknown-elf-gcc -march=rv32ia -mabi=ilp32 ~/hello.c -nostdlib
// No error emitted, because compile only.
$ riscv64-unknown-elf-gcc -march=rv32ia -mabi=ilp32 ~/hello.c -c
gcc/ChangeLog:
* common/config/riscv/riscv-common.c: Include <vector>.
(struct riscv_multi_lib_info_t): New.
(riscv_subset_list::match_score): Ditto.
(find_last_appear_switch): Ditto.
(struct multi_lib_info_t): Ditto.
(riscv_current_arch_str): Ditto.
(riscv_current_abi_str): Ditto.
(riscv_multi_lib_info_t::parse): Ditto.
(riscv_check_cond): Ditto.
(riscv_check_other_cond): Ditto.
(riscv_compute_multilib): Ditto.
(TARGET_COMPUTE_MULTILIB): Defined.
* config/riscv/elf.h (LIB_SPEC): Call riscv_multi_lib_check if
doing link.
(RISCV_USE_CUSTOMISED_MULTI_LIB): New.
* config/riscv/riscv.h (riscv_multi_lib_check): New.
(EXTRA_SPEC_FUNCTIONS): Add riscv_multi_lib_check.
---
gcc/common/config/riscv/riscv-common.c | 409 +++++++++++++++++++++++++
gcc/config/riscv/elf.h | 6 +-
gcc/config/riscv/riscv-subset.h | 2 +
gcc/config/riscv/riscv.h | 4 +-
4 files changed, 419 insertions(+), 2 deletions(-)
diff --git a/gcc/common/config/riscv/riscv-common.c b/gcc/common/config/riscv/riscv-common.c
index 10868fd417d..83819a7de6a 100644
--- a/gcc/common/config/riscv/riscv-common.c
+++ b/gcc/common/config/riscv/riscv-common.c
@@ -18,6 +18,7 @@ along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include <sstream>
+#include <vector>
#define INCLUDE_STRING
#include "config.h"
@@ -122,6 +123,26 @@ const riscv_subset_list *riscv_current_subset_list ()
return current_subset_list;
}
+/* struct for recording multi-lib info. */
+struct riscv_multi_lib_info_t {
+ std::string path;
+ std::string arch_str;
+ std::string abi_str;
+ std::string other_cond;
+ riscv_subset_list *subset_list;
+
+ static bool parse (struct riscv_multi_lib_info_t *,
+ const std::string &,
+ const std::string &);
+};
+
+/* Flag for checking if there is no suitable multi-lib found. */
+static bool riscv_no_matched_multi_lib;
+
+/* Used for record value of -march and -mabi. */
+static std::string riscv_current_arch_str;
+static std::string riscv_current_abi_str;
+
riscv_subset_t::riscv_subset_t ()
: name (), major_version (0), minor_version (0), next (NULL),
explicit_version_p (false), implied_p (false)
@@ -147,6 +168,42 @@ riscv_subset_list::~riscv_subset_list ()
}
}
+/* Compute the match score of two arch string, return 0 if incompatible. */
+int
+riscv_subset_list::match_score (riscv_subset_list *list) const
+{
+ riscv_subset_t *s;
+ int score = 0;
+ bool has_a_ext, list_has_a_ext;
+
+ /* Impossible to match if XLEN is different. */
+ if (list->m_xlen != this->m_xlen)
+ return 0;
+
+ /* There is different code gen in libstdc++ and libatomic between w/ A-ext
+ and w/o A-ext, and it not work if using soft and hard atomic mechanism
+ at same time, so they are incompatible. */
+ has_a_ext = this->lookup ("a") != NULL;
+ list_has_a_ext = list->lookup ("a") != NULL;
+
+ if (has_a_ext != list_has_a_ext)
+ return 0;
+
+
+ /* list must be subset of current this list, otherwise it not safe to
+ link.
+ TODO: We might give different weigth for each extension, but the rule could
+ be complicated.
+ TODO: We might consider the version of each extension. */
+ for (s = list->m_head; s != NULL; s = s->next)
+ if (this->lookup (s->name.c_str ()) != NULL)
+ score++;
+ else
+ return 0;
+
+ return score;
+}
+
/* Get the rank for single-letter subsets, lower value meaning higher
priority. */
@@ -1054,6 +1111,358 @@ riscv_expand_arch_from_cpu (int argc ATTRIBUTE_UNUSED,
return xasprintf ("-march=%s", arch.c_str());
}
+/* Find last switch with the prefix, options are take last one in general,
+ return NULL if not found, and return the option value if found, it could
+ return empty string if the option has no value. */
+
+static const char *
+find_last_appear_switch (
+ const struct switchstr *switches,
+ int n_switches,
+ const char *prefix)
+{
+ int i;
+ size_t len = strlen (prefix);
+
+ for (i = 0; i < n_switches; ++i) {
+ const struct switchstr *this_switch = &switches[n_switches - i - 1];
+
+ if (this_switch->live_cond & SWITCH_FALSE)
+ continue;
+
+ if (strncmp (this_switch->part1, prefix, len) == 0)
+ return this_switch->part1 + len;
+ }
+
+ return NULL;
+}
+
+/* Parse the path and cond string into riscv_multi_lib_info_t, return false
+ if parsing failed. */
+
+bool
+riscv_multi_lib_info_t::parse (
+ struct riscv_multi_lib_info_t *multi_lib_info,
+ const std::string &path,
+ const std::string &cond)
+{
+ const char *default_arch_str = STRINGIZING (TARGET_RISCV_DEFAULT_ARCH);
+ const char *default_abi_str = STRINGIZING (TARGET_RISCV_DEFAULT_ABI);
+ multi_lib_info->other_cond = cond;
+ if (path == ".")
+ {
+ multi_lib_info->arch_str = default_arch_str;
+ multi_lib_info->abi_str = default_abi_str;
+ multi_lib_info->subset_list =
+ riscv_subset_list::parse(
+ STRINGIZING (TARGET_RISCV_DEFAULT_ARCH),
+ input_location);
+ }
+ else
+ {
+ /* XXX: Maybe we should parse that from cond string rather than path. */
+ /* The path rule for RISC-V multi-lib is <arch>/<abi>[/<others>]. */
+ size_t slash_pos = path.find ('/');
+
+ /* Parse failed if not found any `/`. */
+ if (slash_pos == std::string::npos)
+ return false;
+
+ /* Seeking if there is other part in the path. */
+ size_t end_of_abi = path.find ('/', slash_pos + 1);
+
+ multi_lib_info->arch_str = path.substr (0, slash_pos);
+ if (end_of_abi == std::string::npos) {
+ /* Only <arch>/<abi>. */
+ multi_lib_info->abi_str = path.substr (slash_pos + 1,
+ path.length () - 1);
+
+ /* Skip this multi-lib if this configuration is exactly same as
+ default multi-lib settings. */
+ if (multi_lib_info->arch_str == default_arch_str
+ && multi_lib_info->abi_str == default_abi_str)
+ return false;
+
+ } else
+ /* <arch>/<abi>/<others>.... */
+ multi_lib_info->abi_str = path.substr (slash_pos + 1,
+ end_of_abi - slash_pos - 1);
+ }
+
+ multi_lib_info->subset_list =
+ riscv_subset_list::parse(multi_lib_info->arch_str.c_str (), input_location);
+
+ return true;
+}
+
+/* Report error if not found suitable multilib. */
+const char *
+riscv_multi_lib_check (int argc ATTRIBUTE_UNUSED,
+ const char **argv ATTRIBUTE_UNUSED)
+{
+ if (riscv_no_matched_multi_lib)
+ fatal_error (
+ input_location,
+ "Can't found suitable multilib set for %<-march=%s%>/%<-mabi=%s%>",
+ riscv_current_arch_str.c_str (),
+ riscv_current_abi_str.c_str ());
+
+ return "";
+}
+
+static bool
+riscv_check_cond (
+ const struct switchstr *switches,
+ int n_switches,
+ const std::string &arg,
+ bool not_arg)
+{
+ int i;
+ for (i = 0; i < n_switches; ++i) {
+ const struct switchstr *this_switch = &switches[n_switches - i - 1];
+
+ if ((this_switch->live_cond & SWITCH_IGNORE) != 0)
+ continue;
+
+ if (this_switch->live_cond & SWITCH_FALSE)
+ continue;
+
+ if (arg == this_switch->part1)
+ return not_arg ? false : true;
+ }
+
+ /* Not found this arg, that's ok! */
+ return not_arg ? true : false;
+}
+
+/* Check the other cond is found or not, return */
+
+static int
+riscv_check_other_cond (
+ const struct switchstr *switches,
+ int n_switches,
+ int match_score,
+ const std::string &other_cond)
+{
+ const char *p = other_cond.c_str ();
+ const char *this_arg;
+ std::string arg;
+ bool not_arg;
+ bool ok;
+ int ok_count = 0;
+
+ if (match_score == 0)
+ return 0;
+
+ while (*p != '\0')
+ {
+ while (*p == ' ') p++;
+ this_arg = p;
+ while (*p != ' ' && *p != '\0')
+ ++p;
+
+ if (*this_arg != '!')
+ not_arg = false;
+ else
+ {
+ not_arg = true;
+ ++this_arg;
+ }
+
+ arg = std::string (this_arg, p - this_arg);
+
+ /* We might got empty arg when multi-lib is disabled. */
+ if (arg.empty ())
+ continue;
+
+ ok = riscv_check_cond (switches, n_switches, arg, not_arg);
+
+ if (!ok)
+ return -1;
+
+ ok_count++;
+
+ if (*p == '\0') break;
+
+ p++;
+ }
+
+ /* 100 is magic number, it's just used for make sure this multi-lib has
+ higher priority if we found any some option is listed in the option check
+ list. */
+ return match_score + ok_count * 100;
+}
+
+/* We only override this in bare-matel toolchain. */
+#ifdef RISCV_USE_CUSTOMISED_MULTI_LIB
+/* Implement TARGET_COMPUTE_MULTILIB. */
+
+static const char *
+riscv_compute_multilib (
+ const struct switchstr *switches,
+ int n_switches,
+ const char *multilib_dir,
+ const char *multilib_defaults ATTRIBUTE_UNUSED,
+ const char *multilib_select,
+ const char *multilib_matches ATTRIBUTE_UNUSED,
+ const char *multilib_exclusions ATTRIBUTE_UNUSED,
+ const char *multilib_reuse ATTRIBUTE_UNUSED)
+{
+ const char *p, *tp;
+ const char *this_path;
+ const char *this_cond;
+ size_t this_path_len;
+ size_t this_cond_len;
+ size_t offset;
+ bool skip_until_blank;
+ bool result;
+ riscv_no_matched_multi_lib = false;
+ riscv_subset_list *subset_list = NULL;
+
+ std::vector<riscv_multi_lib_info_t> multilib_infos;
+ riscv_multi_lib_info_t multilib_info;
+
+ /* Already found suitable, multi-lib, just use that. */
+ if (multilib_dir != NULL)
+ return multilib_dir;
+
+ /* Find last march. */
+ riscv_current_arch_str =
+ find_last_appear_switch (switches, n_switches, "march=");
+ /* Find mabi. */
+ riscv_current_abi_str =
+ find_last_appear_switch (switches, n_switches, "mabi=");
+
+ /* Failed to find -march or -mabi, but it should not happened since we have
+ set both in OPTION_DEFAULT_SPECS. */
+ if (riscv_current_arch_str.empty () || riscv_current_abi_str.empty ())
+ return multilib_dir;
+
+ subset_list = riscv_subset_list::parse (riscv_current_arch_str.c_str (),
+ input_location);
+
+ /* Failed to parse -march, fallback to using what gcc use. */
+ if (subset_list == NULL)
+ return multilib_dir;
+
+ /* Parsing MULTILIB_SELECT, ignore MULTILIB_REUSE here, we have our own rules.
+ TODO: most codes are grab from gcc.c, maybe we should refine that? */
+ p = multilib_select;
+
+ while (*p != '\0')
+ {
+ /* Ignore newlines. */
+ if (*p == '\n')
+ {
+ ++p;
+ continue;
+ }
+
+ /* Get the initial path. */
+ this_path = p;
+ while (*p != ' ')
+ {
+ if (*p == '\0')
+ {
+ fatal_error (input_location, "multilib select %qs %qs is invalid",
+ multilib_select, multilib_reuse);
+ }
+ ++p;
+ }
+ this_path_len = p - this_path;
+ multilib_info.path = std::string (this_path, this_path_len);
+
+ this_cond = p;
+ while (*p != ';')
+ {
+ if (*p == '\0')
+ {
+ fatal_error (input_location, "multilib select %qs %qs is invalid",
+ multilib_select, multilib_reuse);
+ }
+ ++p;
+ }
+
+ /* Ignore march or mabi option in cond string. */
+ tp = this_cond;
+ skip_until_blank = false;
+
+ while (*tp != ';')
+ {
+ offset = 0;
+ if (*tp == '!')
+ offset = 1;
+
+ if (skip_until_blank && *tp == ' ')
+ {
+ skip_until_blank = false;
+ this_cond = tp + 1;
+ }
+
+ if ((strncmp (tp + offset, "mabi", 4) == 0) ||
+ (strncmp (tp + offset, "march", 5) == 0))
+ skip_until_blank = true;
+
+ ++tp;
+ }
+
+ if (skip_until_blank)
+ this_cond_len = 0;
+ else
+ this_cond_len = p - this_cond;
+
+ result =
+ riscv_multi_lib_info_t::parse (
+ &multilib_info,
+ std::string (this_path, this_path_len),
+ std::string (this_cond, this_cond_len));
+
+ if (result)
+ multilib_infos.push_back (multilib_info);
+
+ p++;
+ }
+
+ int match_score = 0;
+ int max_match_score = 0;
+ int best_match_multi_lib = -1;
+ /* Try to decition which set we should used. */
+ /* We have 3 level dection tree here, ABI, A-ext, check input arch/ABI must be
+ superset of multi-lib arch. */
+ for (size_t i = 0; i < multilib_infos.size (); ++i)
+ {
+ /* Check ABI is same first. */
+ if (riscv_current_abi_str != multilib_infos[i].abi_str)
+ continue;
+
+ /* Found a potential compatible multi-lib setting!
+ Calculate the match score. */
+ match_score = subset_list->match_score (multilib_infos[i].subset_list);
+
+ /* Checking other cond in the multi-lib setting. */
+ match_score = riscv_check_other_cond (switches,
+ n_switches,
+ match_score,
+ multilib_infos[i].other_cond);
+
+ /* Record highest match score multi-lib setting. */
+ if (match_score > max_match_score)
+ best_match_multi_lib = i;
+ }
+
+ if (best_match_multi_lib == -1)
+ {
+ riscv_no_matched_multi_lib = true;
+ return multilib_dir;
+ }
+ else
+ return xstrdup (multilib_infos[best_match_multi_lib].path.c_str ());
+}
+
+#undef TARGET_COMPUTE_MULTILIB
+#define TARGET_COMPUTE_MULTILIB riscv_compute_multilib
+#endif
+
/* Implement TARGET_OPTION_OPTIMIZATION_TABLE. */
static const struct default_options riscv_option_optimization_table[] =
diff --git a/gcc/config/riscv/elf.h b/gcc/config/riscv/elf.h
index 7e65e499031..cc0fd4d9de9 100644
--- a/gcc/config/riscv/elf.h
+++ b/gcc/config/riscv/elf.h
@@ -27,10 +27,14 @@ along with GCC; see the file COPYING3. If not see
/* Link against Newlib libraries, because the ELF backend assumes Newlib.
Handle the circular dependence between libc and libgloss. */
#undef LIB_SPEC
-#define LIB_SPEC "--start-group -lc %{!specs=nosys.specs:-lgloss} --end-group"
+#define LIB_SPEC \
+ "--start-group -lc %{!specs=nosys.specs:-lgloss} --end-group " \
+ "%{!nostartfiles:%{!nodefaultlibs:%{!nolibc:%{!nostdlib:%:riscv_multi_lib_check()}}}}"
#undef STARTFILE_SPEC
#define STARTFILE_SPEC "crt0%O%s crtbegin%O%s"
#undef ENDFILE_SPEC
#define ENDFILE_SPEC "crtend%O%s"
+
+#define RISCV_USE_CUSTOMISED_MULTI_LIB 1
diff --git a/gcc/config/riscv/riscv-subset.h b/gcc/config/riscv/riscv-subset.h
index 793655a01f2..56bb4d0a7a1 100644
--- a/gcc/config/riscv/riscv-subset.h
+++ b/gcc/config/riscv/riscv-subset.h
@@ -88,6 +88,8 @@ public:
const riscv_subset_t *begin () const {return m_head;};
const riscv_subset_t *end () const {return NULL;};
+
+ int match_score (riscv_subset_list *) const;
};
extern const riscv_subset_list *riscv_current_subset_list (void);
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index f47d5b40a66..4d8a4c76c1c 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -50,11 +50,13 @@ along with GCC; see the file COPYING3. If not see
extern const char *riscv_expand_arch (int argc, const char **argv);
extern const char *riscv_expand_arch_from_cpu (int argc, const char **argv);
extern const char *riscv_default_mtune (int argc, const char **argv);
+extern const char *riscv_multi_lib_check (int argc, const char **argv);
# define EXTRA_SPEC_FUNCTIONS \
{ "riscv_expand_arch", riscv_expand_arch }, \
{ "riscv_expand_arch_from_cpu", riscv_expand_arch_from_cpu }, \
- { "riscv_default_mtune", riscv_default_mtune },
+ { "riscv_default_mtune", riscv_default_mtune }, \
+ { "riscv_multi_lib_check", riscv_multi_lib_check },
/* Support for a compile-time default CPU, et cetera. The rules are:
--with-arch is ignored if -march or -mcpu is specified.
--
2.31.1
next prev parent reply other threads:[~2021-07-21 9:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 9:28 [PATCH 0/2] New target hook TARGET_COMPUTE_MULTILIB and implementation for RISC-V Kito Cheng
2021-07-21 9:28 ` [PATCH 1/2] Add TARGET_COMPUTE_MULTILIB hook to override multi-lib result Kito Cheng
2021-09-01 0:16 ` Jim Wilson
2021-07-21 9:28 ` Kito Cheng [this message]
2021-09-01 0:22 ` [PATCH 2/2] RISC-V: Implement TARGET_COMPUTE_MULTILIB Jim Wilson
2021-09-01 0:23 ` Jim Wilson
2021-09-16 4:12 ` Kito Cheng
2022-09-09 7:20 ` Andreas Schwab
2022-09-09 9:58 ` Kito Cheng
2021-07-29 18:44 ` [PATCH 0/2] New target hook TARGET_COMPUTE_MULTILIB and implementation for RISC-V Kito Cheng
2021-07-29 19:00 ` Palmer Dabbelt
2022-09-02 9:28 ` Kito Cheng
-- strict thread matches above, loose matches on Subject: below --
2020-12-01 9:29 [PATCH 1/2] Add TARGET_COMPUTE_MULTILIB hook to override multi-lib result Kito Cheng
2020-12-01 9:29 ` [PATCH 2/2] RISC-V: Implement TARGET_COMPUTE_MULTILIB Kito Cheng
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