* [PATCH v3 1/2] Add TARGET_COMPUTE_MULTILIB hook to override multi-lib result.
2021-09-16 9:38 [PATCH 0/2 v3] New target hook TARGET_COMPUTE_MULTILIB and implementation for RISC-V Kito Cheng
@ 2021-09-16 9:38 ` Kito Cheng
2021-09-16 9:38 ` [PATCH v3 2/2] RISC-V: Implement TARGET_COMPUTE_MULTILIB Kito Cheng
1 sibling, 0 replies; 3+ messages in thread
From: Kito Cheng @ 2021-09-16 9:38 UTC (permalink / raw)
To: gcc-patches, kito.cheng, jimw, palmer, andrew; +Cc: Kito Cheng
Create a new hook to let target could override the multi-lib result,
the motivation is RISC-V might have very complicated multi-lib re-use
rule*, which is hard to maintain and use current multi-lib scripts,
we even hit the "argument list too long" error when we tried to add more
multi-lib reuse rule.
So I think it would be great to have a target specific way to determine
the multi-lib re-use rule, then we could write those rule in C, instead
of expand every possible case in MULTILIB_REUSE.
* Here is an example for RISC-V multi-lib rules:
https://gist.github.com/kito-cheng/0289cd42d9a756382e5afeb77b42b73b
gcc/ChangeLog:
* common/common-target.def (compute_multilib): New.
* common/common-targhooks.c (default_compute_multilib): New.
* doc/tm.texi.in (TARGET_COMPUTE_MULTILIB): New.
* doc/tm.texi: Regen.
* gcc.c: Include common/common-target.h.
(set_multilib_dir) Call targetm_common.compute_multilib.
(SWITCH_LIVE): Move to opts.h.
(SWITCH_FALSE): Ditto.
(SWITCH_IGNORE): Ditto.
(SWITCH_IGNORE_PERMANENTLY): Ditto.
(SWITCH_KEEP_FOR_GCC): Ditto.
(struct switchstr): Ditto.
* opts.h (SWITCH_LIVE): Move from gcc.c.
(SWITCH_FALSE): Ditto.
(SWITCH_IGNORE): Ditto.
(SWITCH_IGNORE_PERMANENTLY): Ditto.
(SWITCH_KEEP_FOR_GCC): Ditto.
(struct switchstr): Ditto.
---
gcc/common/common-target.def | 25 ++++++++++++++++++
gcc/common/common-targhooks.c | 15 +++++++++++
gcc/doc/tm.texi | 17 +++++++++++++
gcc/doc/tm.texi.in | 3 +++
gcc/gcc.c | 48 +++++++++--------------------------
gcc/opts.h | 36 ++++++++++++++++++++++++++
6 files changed, 108 insertions(+), 36 deletions(-)
diff --git a/gcc/common/common-target.def b/gcc/common/common-target.def
index f54590a2a54..b7cf713770c 100644
--- a/gcc/common/common-target.def
+++ b/gcc/common/common-target.def
@@ -84,6 +84,31 @@ The result will be pruned to cases with PREFIX if not NULL.",
vec<const char *>, (int option_code, const char *prefix),
default_get_valid_option_values)
+DEFHOOK
+(compute_multilib,
+ "Some targets like RISC-V might have complicated multilib reuse rules which\n\
+are hard to implement with the current multilib scheme. This hook allows\n\
+targets to override the result from the built-in multilib mechanism.\n\
+@var{switches} is the raw option list with @var{n_switches} items;\n\
+@var{multilib_dir} is the multi-lib result which is computed by the built-in\n\
+multi-lib mechanism;\n\
+@var{multilib_defaults} is the default options list for multi-lib;\n\
+@var{multilib_select} is the string containing the list of supported\n\
+multi-libs, and the option checking list.\n\
+@var{multilib_matches}, @var{multilib_exclusions}, and @var{multilib_reuse}\n\
+are corresponding to @var{MULTILIB_MATCHES}, @var{MULTILIB_EXCLUSIONS},\n\
+and @var{MULTILIB_REUSE}.\n\
+The default definition does nothing but return @var{multilib_dir} directly.",
+ const char *, (const struct switchstr *switches,
+ int n_switches,
+ const char *multilib_dir,
+ const char *multilib_defaults,
+ const char *multilib_select,
+ const char *multilib_matches,
+ const char *multilib_exclusions,
+ const char *multilib_reuse),
+ default_compute_multilib)
+
/* Leave the boolean fields at the end. */
/* True if unwinding tables should be generated by default. */
diff --git a/gcc/common/common-targhooks.c b/gcc/common/common-targhooks.c
index 325f199bff3..1477aeeb536 100644
--- a/gcc/common/common-targhooks.c
+++ b/gcc/common/common-targhooks.c
@@ -90,3 +90,18 @@ const struct default_options empty_optimization_table[] =
{
{ OPT_LEVELS_NONE, 0, NULL, 0 }
};
+
+/* Default version of TARGET_COMPUTE_MULTILIB. */
+const char *
+default_compute_multilib(
+ const struct switchstr *,
+ int,
+ const char *multilib,
+ const char *,
+ const char *,
+ const char *,
+ const char *,
+ const char *)
+{
+ return multilib;
+}
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index be8148583d8..6f1e0293b6c 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -778,6 +778,23 @@ options are changed via @code{#pragma GCC optimize} or by using the
Set target-dependent initial values of fields in @var{opts}.
@end deftypefn
+@deftypefn {Common Target Hook} {const char *} TARGET_COMPUTE_MULTILIB (const struct switchstr *@var{switches}, int @var{n_switches}, const char *@var{multilib_dir}, const char *@var{multilib_defaults}, const char *@var{multilib_select}, const char *@var{multilib_matches}, const char *@var{multilib_exclusions}, const char *@var{multilib_reuse})
+Some targets like RISC-V might have complicated multilib reuse rules which
+are hard to implement with the current multilib scheme. This hook allows
+targets to override the result from the built-in multilib mechanism.
+@var{switches} is the raw option list with @var{n_switches} items;
+@var{multilib_dir} is the multi-lib result which is computed by the built-in
+multi-lib mechanism;
+@var{multilib_defaults} is the default options list for multi-lib;
+@var{multilib_select} is the string containing the list of supported
+multi-libs, and the option checking list.
+@var{multilib_matches}, @var{multilib_exclusions}, and @var{multilib_reuse}
+are corresponding to @var{MULTILIB_MATCHES}, @var{MULTILIB_EXCLUSIONS},
+and @var{MULTILIB_REUSE}.
+The default definition does nothing but return @var{multilib_dir} directly.
+@end deftypefn
+
+
@defmac SWITCHABLE_TARGET
Some targets need to switch between substantially different subtargets
during compilation. For example, the MIPS target has one subtarget for
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index d088eee4afe..ad78439ea61 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -736,6 +736,9 @@ options are changed via @code{#pragma GCC optimize} or by using the
@hook TARGET_OPTION_INIT_STRUCT
+@hook TARGET_COMPUTE_MULTILIB
+
+
@defmac SWITCHABLE_TARGET
Some targets need to switch between substantially different subtargets
during compilation. For example, the MIPS target has one subtarget for
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 3e98bc7973e..dafe754267a 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -43,6 +43,7 @@ compilation is specified by a string called a "spec". */
#include "opts.h"
#include "filenames.h"
#include "spellcheck.h"
+#include "common/common-target.h"
\f
@@ -3573,42 +3574,6 @@ execute (void)
}
}
\f
-/* Find all the switches given to us
- and make a vector describing them.
- The elements of the vector are strings, one per switch given.
- If a switch uses following arguments, then the `part1' field
- is the switch itself and the `args' field
- is a null-terminated vector containing the following arguments.
- Bits in the `live_cond' field are:
- SWITCH_LIVE to indicate this switch is true in a conditional spec.
- SWITCH_FALSE to indicate this switch is overridden by a later switch.
- SWITCH_IGNORE to indicate this switch should be ignored (used in %<S).
- SWITCH_IGNORE_PERMANENTLY to indicate this switch should be ignored.
- SWITCH_KEEP_FOR_GCC to indicate that this switch, otherwise ignored,
- should be included in COLLECT_GCC_OPTIONS.
- in all do_spec calls afterwards. Used for %<S from self specs.
- The `known' field describes whether this is an internal switch.
- The `validated' field describes whether any spec has looked at this switch;
- if it remains false at the end of the run, the switch must be meaningless.
- The `ordering' field is used to temporarily mark switches that have to be
- kept in a specific order. */
-
-#define SWITCH_LIVE (1 << 0)
-#define SWITCH_FALSE (1 << 1)
-#define SWITCH_IGNORE (1 << 2)
-#define SWITCH_IGNORE_PERMANENTLY (1 << 3)
-#define SWITCH_KEEP_FOR_GCC (1 << 4)
-
-struct switchstr
-{
- const char *part1;
- const char **args;
- unsigned int live_cond;
- bool known;
- bool validated;
- bool ordering;
-};
-
static struct switchstr *switches;
static int n_switches;
@@ -9855,6 +9820,17 @@ set_multilib_dir (void)
++p;
}
+ multilib_dir =
+ targetm_common.compute_multilib (
+ switches,
+ n_switches,
+ multilib_dir,
+ multilib_defaults,
+ multilib_select,
+ multilib_matches,
+ multilib_exclusions,
+ multilib_reuse);
+
if (multilib_dir == NULL && multilib_os_dir != NULL
&& strcmp (multilib_os_dir, ".") == 0)
{
diff --git a/gcc/opts.h b/gcc/opts.h
index bafc790112b..f99a469364c 100644
--- a/gcc/opts.h
+++ b/gcc/opts.h
@@ -500,4 +500,40 @@ extern char *gen_producer_string (const char *language_string,
} \
while (false)
+/* Find all the switches given to us
+ and make a vector describing them.
+ The elements of the vector are strings, one per switch given.
+ If a switch uses following arguments, then the `part1' field
+ is the switch itself and the `args' field
+ is a null-terminated vector containing the following arguments.
+ Bits in the `live_cond' field are:
+ SWITCH_LIVE to indicate this switch is true in a conditional spec.
+ SWITCH_FALSE to indicate this switch is overridden by a later switch.
+ SWITCH_IGNORE to indicate this switch should be ignored (used in %<S).
+ SWITCH_IGNORE_PERMANENTLY to indicate this switch should be ignored.
+ SWITCH_KEEP_FOR_GCC to indicate that this switch, otherwise ignored,
+ should be included in COLLECT_GCC_OPTIONS.
+ in all do_spec calls afterwards. Used for %<S from self specs.
+ The `known' field describes whether this is an internal switch.
+ The `validated' field describes whether any spec has looked at this switch;
+ if it remains false at the end of the run, the switch must be meaningless.
+ The `ordering' field is used to temporarily mark switches that have to be
+ kept in a specific order. */
+
+#define SWITCH_LIVE (1 << 0)
+#define SWITCH_FALSE (1 << 1)
+#define SWITCH_IGNORE (1 << 2)
+#define SWITCH_IGNORE_PERMANENTLY (1 << 3)
+#define SWITCH_KEEP_FOR_GCC (1 << 4)
+
+struct switchstr
+{
+ const char *part1;
+ const char **args;
+ unsigned int live_cond;
+ bool known;
+ bool validated;
+ bool ordering;
+};
+
#endif
--
2.33.0
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v3 2/2] RISC-V: Implement TARGET_COMPUTE_MULTILIB
2021-09-16 9:38 [PATCH 0/2 v3] New target hook TARGET_COMPUTE_MULTILIB and implementation for RISC-V Kito Cheng
2021-09-16 9:38 ` [PATCH v3 1/2] Add TARGET_COMPUTE_MULTILIB hook to override multi-lib result Kito Cheng
@ 2021-09-16 9:38 ` Kito Cheng
1 sibling, 0 replies; 3+ messages in thread
From: Kito Cheng @ 2021-09-16 9:38 UTC (permalink / raw)
To: gcc-patches, kito.cheng, jimw, palmer, andrew; +Cc: Kito Cheng
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.
(prefixed_with): 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_conds): 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 | 377 +++++++++++++++++++++++++
gcc/config/riscv/elf.h | 6 +-
gcc/config/riscv/riscv-subset.h | 2 +
gcc/config/riscv/riscv.h | 4 +-
4 files changed, 387 insertions(+), 2 deletions(-)
diff --git a/gcc/common/config/riscv/riscv-common.c b/gcc/common/config/riscv/riscv-common.c
index 10868fd417d..d87418c02a6 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::vector<std::string> conds;
+ riscv_subset_list *subset_list;
+
+ static bool parse (struct riscv_multi_lib_info_t *,
+ const std::string &,
+ const std::vector<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 weight 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 +1111,326 @@ 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;
+}
+
+/* Utils functions to check STR is start with PREFIX or not. */
+
+static bool
+prefixed_with (const std::string &str, const char *prefix)
+{
+ return strncmp (prefix, str.c_str (), strlen (prefix)) == 0;
+}
+
+/* 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::vector<std::string> &conds)
+{
+ const char *default_arch_str = STRINGIZING (TARGET_RISCV_DEFAULT_ARCH);
+ const char *default_abi_str = STRINGIZING (TARGET_RISCV_DEFAULT_ABI);
+ multi_lib_info->conds = conds;
+ if (path == ".")
+ {
+ multi_lib_info->arch_str = default_arch_str;
+ multi_lib_info->abi_str = default_abi_str;
+ }
+ else
+ {
+ std::vector<std::string>::const_iterator itr;
+ for (itr = conds.begin (); itr != conds.end (); ++itr)
+ if (prefixed_with (*itr, "march="))
+ multi_lib_info->arch_str = itr->c_str () + strlen ("march=");
+ else if (prefixed_with (*itr, "mabi="))
+ multi_lib_info->abi_str = itr->c_str () + strlen ("mabi=");
+
+ /* 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;
+ }
+
+ 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 find suitable multilib set for %<-march=%s%>/%<-mabi=%s%>",
+ riscv_current_arch_str.c_str (),
+ riscv_current_abi_str.c_str ());
+
+ return "";
+}
+
+/* Checking ARG is not appeared in SWITCHES if NOT_ARG is set or
+ ARG is appeared if NOT_ARG is not set. */
+
+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;
+
+ /* ARG should not appear if NOT_ARG is set. */
+ if (arg == this_switch->part1)
+ return not_arg ? false : true;
+ }
+
+ /* Not found ARG? that's ok if NOT_ARG is not set. */
+ return not_arg ? true : false;
+}
+
+/* Check the other cond is found or not, return -1 if we should reject this
+ multi-lib option set, otherwise return updated MATCH_SCORE. */
+
+static int
+riscv_check_conds (
+ const struct switchstr *switches,
+ int n_switches,
+ int match_score,
+ const std::vector<std::string> &conds)
+{
+ bool not_arg;
+ bool ok;
+ int ok_count = 0;
+ std::vector<std::string>::const_iterator itr;
+ const char *checking_arg;
+
+ if (match_score == 0)
+ return 0;
+
+ for (itr = conds.begin (); itr != conds.end (); ++itr)
+ {
+ /* We'll check march= and mabi= in ohter place. */
+ if (prefixed_with (*itr, "march=") || prefixed_with (*itr, "mabi="))
+ continue;
+
+ checking_arg = itr->c_str ();
+ if (checking_arg[0] == '!')
+ {
+ not_arg = true;
+ /* Skip '!'. */
+ checking_arg = checking_arg + 1;
+ }
+ else
+ not_arg = false;
+
+ ok = riscv_check_cond (switches, n_switches, checking_arg, not_arg);
+
+ if (!ok)
+ return -1;
+
+ ok_count++;
+ }
+
+ /* 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-metal 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;
+ const char *this_path;
+ size_t this_path_len;
+ bool result;
+ riscv_no_matched_multi_lib = false;
+ riscv_subset_list *subset_list = NULL;
+
+ std::vector<riscv_multi_lib_info_t> multilib_infos;
+ std::vector<std::string> option_conds;
+ std::string option_cond;
+ riscv_multi_lib_info_t multilib_info;
+
+ /* Already found suitable, multi-lib, just use that. */
+ if (multilib_dir != NULL)
+ return multilib_dir;
+
+ /* Find 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;
+ }
+
+ /* Format of each multilib:
+ <path> <opt1> <opt2> ... <optN>; */
+ /* Get the 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);
+
+ option_conds.clear ();
+ /* Pasrse option check list into vector<string>.
+ e.g. "march=rv64imafd mabi=lp64 !mcmodel=medany" to
+ ["march=rv64imafd", "mabi=lp64", "!mcmodel=medany"]. */
+ while (*p != ';')
+ {
+ option_cond = "";
+ /* Skip space. */
+ while (*p == ' ') p++;
+
+ while (*p && *p != ' ' && *p != ';')
+ option_cond.push_back (*p++);
+
+ /* Ignore `!march=` and `!mabi=`, we will handle march and mabi
+ later. */
+ if (option_cond.size ()
+ && !prefixed_with (option_cond, "!march=")
+ && !prefixed_with (option_cond, "!mabi="))
+ option_conds.push_back (option_cond);
+ }
+
+ result =
+ riscv_multi_lib_info_t::parse (
+ &multilib_info,
+ std::string (this_path, this_path_len),
+ option_conds);
+
+ 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 decision which set we should used. */
+ /* We have 3 level decision tree here, ABI, check input arch/ABI must
+ be superset of multi-lib arch, and other rest option checking. */
+ 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_conds (switches,
+ n_switches,
+ match_score,
+ multilib_infos[i].conds);
+
+ /* 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.
--
2.33.0
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