[REVIEW ONLY 0/3] RISC-V: MOCK: Add 'Zce' extension support

[REVIEW ONLY 0/3] RISC-V: MOCK: Add 'Zce' extension support

[Tsukasa OI]

Hi,

This patch set reflects rather complex implications derived
from 'Zce' and 'F'.

They are the expansions related in this context:

'Zce'       == 'Zce' + 'Zca' + 'Zcb' + 'Zcmp' + 'Zcmt'
'Zce' + 'F' == 'Zce' + 'Zca' + 'Zcb' + 'Zcmp' + 'Zcmt' + 'Zcf' + 'F' (RV32)
'Zce' + 'F' == 'Zce' + 'Zca' + 'Zcb' + 'Zcmp' + 'Zcmt'         + 'F' (RV64)

Unlike my related patchset ('C' expansions)
<https://sourceware.org/pipermail/binutils/2023-July/128639.html>,

this is going to be mandatory because those expansions are explicitly stated
in the code size reduction specification.  So, even if 'C' extension should
not be expanded, new complex implication (as in PATCH 1) will be required.


Note however, that 'Zcmp' and 'Zcmt' extensions are not merged into GNU
Binutils yet.  So, this patch set cannot be applied as-is.

So, **consider PATCH 2-3 of this patch set to be a mockup** outlining what
will be required when support for 'Zcmp' and 'Zcmt' extensions are merged
and we are ready to implement support for the 'Zce' superset extension.

On the other hand, I think PATCH 1 can be merged into master because it
does not contain any unratified extensions / debatable choices.


Thanks,
Tsukasa




Tsukasa OI (3):
  RISC-V: Base for complex extension implications
  MOCK: RISC-V: Add 'Zce' extension support
  MOCK: RISC-V: Tests for 'Zce' implications

 bfd/elfxx-riscv.c                             | 61 ++++++++++++++-----
 .../gas/riscv/march-imply-zce-f-32.d          |  6 ++
 .../gas/riscv/march-imply-zce-f-64.d          |  6 ++
 gas/testsuite/gas/riscv/march-imply-zce.d     |  6 ++
 4 files changed, 65 insertions(+), 14 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce-f-32.d
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce-f-64.d
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce.d


base-commit: 8e72ee1de8df0789c0ac593467d34387af388c83
-- 
2.41.0

[REVIEW ONLY 1/3] RISC-V: Base for complex extension implications

[Tsukasa OI]

From: Tsukasa OI <research_trasio@irq.a4lg.com>

Thanks to the commit 48558a5e5471 ("RISC-V: Allow nested implications for
extensions"), we can write complex extension implications in theory.
However, to actually do that, we need to pass more information to
check_func.

For example, we want to imply 'Zcf' from 'F' if and only if the 'Zce'
extension is also enabled and XLEN is 32.  Passing rps is a way to
enable this.

This commit prepares for such complex extension implications.

bfd/ChangeLog:

	* elfxx-riscv.c (struct riscv_implicit_subset) Move around and
	change check_func function prototype.
	(check_implicit_always): New arguments.
	(check_implicit_for_i): Likewise.
	(riscv_implicit_subsets): Add comment for this variable.
	(riscv_parse_add_implicit_subsets): Call check_func with
	new arguments.
---
 bfd/elfxx-riscv.c | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index ba5165766b2b..06ac521bdf27 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1064,11 +1064,25 @@ riscv_elf_ignore_reloc (bfd *abfd ATTRIBUTE_UNUSED,
   return bfd_reloc_ok;
 }
 
+/* Record all implicit information for the subsets.  */
+
+typedef struct riscv_implicit_subset
+{
+  const char *subset_name;
+  const char *implicit_name;
+  /* A function to determine if we need to add the implicit subset.  */
+  bool (*check_func) (const riscv_parse_subset_t *,
+		      const struct riscv_implicit_subset *,
+		      const riscv_subset_t *);
+} riscv_implicit_subset_t;
+
 /* Always add the IMPLICIT for the SUBSET.  */
 
 static bool
-check_implicit_always (const char *implicit ATTRIBUTE_UNUSED,
-		       riscv_subset_t *subset ATTRIBUTE_UNUSED)
+check_implicit_always (const riscv_parse_subset_t *rps ATTRIBUTE_UNUSED,
+		       const riscv_implicit_subset_t *implicit
+			   ATTRIBUTE_UNUSED,
+		       const riscv_subset_t *subset ATTRIBUTE_UNUSED)
 {
   return true;
 }
@@ -1076,23 +1090,18 @@ check_implicit_always (const char *implicit ATTRIBUTE_UNUSED,
 /* Add the IMPLICIT only when the version of SUBSET less than 2.1.  */
 
 static bool
-check_implicit_for_i (const char *implicit ATTRIBUTE_UNUSED,
-		      riscv_subset_t *subset)
+check_implicit_for_i (const riscv_parse_subset_t *rps ATTRIBUTE_UNUSED,
+		      const riscv_implicit_subset_t *implicit ATTRIBUTE_UNUSED,
+		      const riscv_subset_t *subset)
 {
   return (subset->major_version < 2
 	  || (subset->major_version == 2
 	      && subset->minor_version < 1));
 }
 
-/* Record all implicit information for the subsets.  */
-struct riscv_implicit_subset
-{
-  const char *subset_name;
-  const char *implicit_name;
-  /* A function to determine if we need to add the implicit subset.  */
-  bool (*check_func) (const char *, riscv_subset_t *);
-};
-static struct riscv_implicit_subset riscv_implicit_subsets[] =
+/* All extension implications.  */
+
+static riscv_implicit_subset_t riscv_implicit_subsets[] =
 {
   {"e", "i",		check_implicit_always},
   {"i", "zicsr",	check_implicit_for_i},
@@ -1900,7 +1909,7 @@ riscv_parse_extensions (riscv_parse_subset_t *rps,
 static void
 riscv_parse_add_implicit_subsets (riscv_parse_subset_t *rps)
 {
-  struct riscv_implicit_subset *t = riscv_implicit_subsets;
+  riscv_implicit_subset_t *t = riscv_implicit_subsets;
   bool finished = false;
   while (!finished)
     {
@@ -1912,7 +1921,7 @@ riscv_parse_add_implicit_subsets (riscv_parse_subset_t *rps)
 	  if (riscv_lookup_subset (rps->subset_list, t->subset_name, &subset)
 	      && !riscv_lookup_subset (rps->subset_list, t->implicit_name,
 				       &implicit_subset)
-	      && t->check_func (t->implicit_name, subset))
+	      && t->check_func (rps, t, subset))
 	    {
 	      riscv_parse_add_subset (rps, t->implicit_name,
 				      RISCV_UNKNOWN_VERSION,
-- 
2.41.0

[REVIEW ONLY 2/3] MOCK: RISC-V: Add 'Zce' extension support

[Tsukasa OI]

From: Tsukasa OI <research_trasio@irq.a4lg.com>

It adds a support for the 'Zce' superset compressed instruction extension
for embedded systems.

**THIS IS A MOCKUP**

Since 'Zcmp' and 'Zcmt' are not added to GNU Binutils yet, this commit is
just a mockup.  However, it outlines what will be required on the 'Zce'
support along with new complex implication design.

bfd/ChangeLog:

	* elfxx-riscv.c (check_implicit_for_f_zce): New function to check
	whether adding implication 'F' -> 'Zcf' is appropriate.
	(riscv_implicit_subsets): Add conditional implication from 'F'
	-> 'Zcf'.  (riscv_supported_std_z_ext): [MOCK] Add 'Zce' to the
	supported 'Z' extension list.
---
 bfd/elfxx-riscv.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 06ac521bdf27..94487306fae5 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1099,6 +1099,20 @@ check_implicit_for_i (const riscv_parse_subset_t *rps ATTRIBUTE_UNUSED,
 	      && subset->minor_version < 1));
 }
 
+/* Add the IMPLICIT only when the 'Zce' extension is also available
+   and XLEN is 32.  */
+
+static bool
+check_implicit_for_f_zce (const riscv_parse_subset_t *rps,
+			  const riscv_implicit_subset_t *implicit
+			      ATTRIBUTE_UNUSED,
+			  const riscv_subset_t *subset ATTRIBUTE_UNUSED)
+{
+  riscv_subset_t *tmp = NULL;
+  return *rps->xlen == 32
+	 && riscv_lookup_subset (rps->subset_list, "zce", &tmp);
+}
+
 /* All extension implications.  */
 
 static riscv_implicit_subset_t riscv_implicit_subsets[] =
@@ -1184,6 +1198,10 @@ static riscv_implicit_subset_t riscv_implicit_subsets[] =
   {"zvksg", "zvkg",	check_implicit_always},
   {"zvksc", "zvks",	check_implicit_always},
   {"zvksc", "zvbc",	check_implicit_always},
+  {"zce", "zca",	check_implicit_always},
+  {"zce", "zcb",	check_implicit_always},
+  {"zce", "zcmp",	check_implicit_always},
+  {"zce", "zcmt",	check_implicit_always},
   {"zcf", "zca",	check_implicit_always},
   {"zcd", "zca",	check_implicit_always},
   {"zcb", "zca",	check_implicit_always},
@@ -1194,6 +1212,9 @@ static riscv_implicit_subset_t riscv_implicit_subsets[] =
   {"sscofpmf", "zicsr",		check_implicit_always},
   {"ssstateen", "zicsr",	check_implicit_always},
   {"sstc", "zicsr",		check_implicit_always},
+  /* Complex implications (that should be checked after others).  */
+  {"f", "zcf",		check_implicit_for_f_zce},
+  /* Tail of the list.  */
   {NULL, NULL, NULL}
 };
 
@@ -1325,6 +1346,10 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
   {"zcb",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zcf",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zcd",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  /* MOCK: uncomment those lines once ready.  */
+  // {"zce",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  // {"zcmp",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  // {"zcmt",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {NULL, 0, 0, 0, 0}
 };
 
-- 
2.41.0

[REVIEW ONLY 3/3] MOCK: RISC-V: Tests for 'Zce' implications

[Tsukasa OI]

From: Tsukasa OI <research_trasio@irq.a4lg.com>

**NEVER COMMIT THIS.**

This commit is intended to be merged to the previous patch once 'Zcmp'
and 'Zcmt' extensions are ready.

It adds several tests related to 'Zce' implications.

bfd/ChangeLog:

	* elfxx-riscv.c: [MOCK] Uncomment mock lines to pass the test.

gas/ChangeLog:

	* testsuite/gas/riscv/march-imply-zce.d: New test.
	* testsuite/gas/riscv/march-imply-zce-f-32.d: Likewise.
	* testsuite/gas/riscv/march-imply-zce-f-64.d: Likewise.
---
 bfd/elfxx-riscv.c                              | 7 +++----
 gas/testsuite/gas/riscv/march-imply-zce-f-32.d | 6 ++++++
 gas/testsuite/gas/riscv/march-imply-zce-f-64.d | 6 ++++++
 gas/testsuite/gas/riscv/march-imply-zce.d      | 6 ++++++
 4 files changed, 21 insertions(+), 4 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce-f-32.d
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce-f-64.d
 create mode 100644 gas/testsuite/gas/riscv/march-imply-zce.d

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 94487306fae5..583a10c2794b 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1346,10 +1346,9 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
   {"zcb",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zcf",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zcd",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
-  /* MOCK: uncomment those lines once ready.  */
-  // {"zce",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
-  // {"zcmp",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
-  // {"zcmt",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zce",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zcmp",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zcmt",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {NULL, 0, 0, 0, 0}
 };
 
diff --git a/gas/testsuite/gas/riscv/march-imply-zce-f-32.d b/gas/testsuite/gas/riscv/march-imply-zce-f-32.d
new file mode 100644
index 000000000000..e0cca82e0a08
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-imply-zce-f-32.d
@@ -0,0 +1,6 @@
+#as: -march=rv32if_zce -march-attr -misa-spec=20191213
+#readelf: -A
+#source: empty.s
+Attribute Section: riscv
+File Attributes
+  Tag_RISCV_arch: "rv32i2p1_f2p2_zicsr2p0_zca1p0_zcb1p0_zce1p0_zcf1p0_zcmp1p0_zcmt1p0"
diff --git a/gas/testsuite/gas/riscv/march-imply-zce-f-64.d b/gas/testsuite/gas/riscv/march-imply-zce-f-64.d
new file mode 100644
index 000000000000..f0ccd7a3fce5
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-imply-zce-f-64.d
@@ -0,0 +1,6 @@
+#as: -march=rv64if_zce -march-attr -misa-spec=20191213
+#readelf: -A
+#source: empty.s
+Attribute Section: riscv
+File Attributes
+  Tag_RISCV_arch: "rv64i2p1_f2p2_zicsr2p0_zca1p0_zcb1p0_zce1p0_zcmp1p0_zcmt1p0"
diff --git a/gas/testsuite/gas/riscv/march-imply-zce.d b/gas/testsuite/gas/riscv/march-imply-zce.d
new file mode 100644
index 000000000000..2a4ab4e1b639
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-imply-zce.d
@@ -0,0 +1,6 @@
+#as: -march=rv32i_zce -march-attr -misa-spec=20191213
+#readelf: -A
+#source: empty.s
+Attribute Section: riscv
+File Attributes
+  Tag_RISCV_arch: "rv32i2p1_zca1p0_zcb1p0_zce1p0_zcmp1p0_zcmt1p0"
-- 
2.41.0