[PATCH] RISC-V: Output mapping symbols with ISA string once .option arch is used.

[Nelson Chu <nelson.chu@sifive.com>]

[1] Proposal: Extend .option directive for control enabled extensions on
specific code region,
https://github.com/riscv-non-isa/riscv-asm-manual/pull/67

[2] Proposal: Add mapping symbol,
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/196

Originally, the extended .option directive [1] was used to resolve the known
ifunc issue, but it also allows users to enable and disable extensions of a
certain code region at will.  Once the extensions have overlapped encodings,
it is difficult to dump the instructions correctly for now.  Therefore, the
mapping symbols with ISA string [2] for different code regions was proposed
to resolve the dump issue, and this patch is for that purpose.

The riscv-gnu-toolchain regressions passed for this patch.

gas/
    * config/tc-riscv.c (updated_riscv_subsets): New boolean.  Output the
    instruction mapping symbols with ISA string if it is true, otherwise
    set it to false.
    (remove_mapping_symbol): New function.  Remove the previous mapping
    symbol by checking the current one.
    (make_mapping_symbol): Added the current ISA string to $x when
    updated_riscv_subsets is true.  Besides, call remove_mapping_symbol
    rather than jusr remove the previous symbol.
    (riscv_mapping_state): Handle new mapping type MAP_INSN_ARCH, and also
    call remove_mapping_symbol before removing it.
    (s_riscv_option): Set updated_riscv_subsets to true once we meet .option
    rvc/norvc/arch/pop directives.
    * testsuite/gas/riscv/mapping-01a.d: Updated.
    * testsuite/gas/riscv/mapping-02a.d: Likewise.
    * testsuite/gas/riscv/mapping-03a.d: Likewise.
    * testsuite/gas/riscv/mapping-04a.d: Likewise.
    * testsuite/gas/riscv/mapping-norelax-03a.d: Likewise.
    * testsuite/gas/riscv/mapping-norelax-04a.d: Likewise.
    * testsuite/gas/riscv/option-arch-01a.d: Dump frcsr since f should be
    enabled in that code region.
include/
    * opcode/riscv.h (enum riscv_seg_mstat): Added MAP_INSN_ARCH, means
    instructions with specific extensions.
opcodes/
    * riscv-dis.c (riscv_disassemble_insn): Set riscv_fpr_names back to
    riscv_fpr_names_abi or riscv_fpr_names_numeric when zfinx is disabled
    for some specfic code region.
    (riscv_get_map_state): Recognized mapping symbols with ISA, and then
    reset the architecture string once the ISA is different.
---
 gas/config/tc-riscv.c                         | 63 ++++++++++++++++++++++-----
 gas/testsuite/gas/riscv/mapping-01a.d         |  2 +-
 gas/testsuite/gas/riscv/mapping-02a.d         |  2 +-
 gas/testsuite/gas/riscv/mapping-03a.d         |  2 +-
 gas/testsuite/gas/riscv/mapping-04a.d         |  2 +-
 gas/testsuite/gas/riscv/mapping-norelax-03a.d |  2 +-
 gas/testsuite/gas/riscv/mapping-norelax-04a.d |  2 +-
 gas/testsuite/gas/riscv/option-arch-01a.d     |  2 +-
 include/opcode/riscv.h                        |  1 +
 opcodes/riscv-dis.c                           | 12 ++++-
 10 files changed, 71 insertions(+), 19 deletions(-)

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 34ce68e..f61dd86 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -282,6 +282,9 @@ struct riscv_option_stack
 
 static struct riscv_option_stack *riscv_opts_stack = NULL;
 
+/* Output the instruction mapping symbols with ISA string if it is true.  */
+static bool updated_riscv_subsets = false;
+
 /* Set which ISA and extensions are available.  */
 
 static void
@@ -445,6 +448,22 @@ static char *expr_end;
 #define OPCODE_MATCHES(OPCODE, OP) \
   (((OPCODE) & MASK_##OP) == MATCH_##OP)
 
+/* Remove PREVIOUS mapping symbol by checking the CURRENT.  */
+
+static void
+remove_mapping_symbol (symbolS *previous, symbolS *current)
+{
+  /* If the mapping symbol we add isn't MAP_INSN_ARCH, but
+     the removed previous mapping symbol is MAP_INSN_ARCH,
+     then the next MAP_INSN should be converted to MAP_INSN_ARCH.  */
+  if (current != NULL
+      && !strncmp (S_GET_NAME (current), "$xrv", 4) == 0
+      && strncmp (S_GET_NAME (previous), "$xrv", 4) == 0)
+    updated_riscv_subsets = true;
+
+  symbol_remove (previous, &symbol_rootP, &symbol_lastP);
+}
+
 /* Create a new mapping symbol for the transition to STATE.  */
 
 static void
@@ -452,14 +471,28 @@ make_mapping_symbol (enum riscv_seg_mstate state,
 		     valueT value,
 		     fragS *frag)
 {
-  const char *name;
+  const char *name = NULL;
+  char *buff = NULL;
+
   switch (state)
     {
     case MAP_DATA:
       name = "$d";
       break;
     case MAP_INSN:
-      name = "$x";
+    case MAP_INSN_ARCH:
+      if (updated_riscv_subsets)
+	{
+	  char *isa = riscv_arch_str (xlen, riscv_subsets);
+	  size_t size = strlen (isa) + 3; /* "rv" + '\0'  */
+	  buff = xmalloc (size);
+	  snprintf (buff, size, "$x%s", isa);
+	  xfree ((void *) isa);
+	  name = buff;
+	  updated_riscv_subsets = false;
+	}
+      else
+	name = "$x";
       break;
     default:
       abort ();
@@ -467,19 +500,19 @@ make_mapping_symbol (enum riscv_seg_mstate state,
 
   symbolS *symbol = symbol_new (name, now_seg, frag, value);
   symbol_get_bfdsym (symbol)->flags |= (BSF_NO_FLAGS | BSF_LOCAL);
+  xfree ((void *) buff);
 
   /* If .fill or other data filling directive generates zero sized data,
      or we are adding odd alignemnts, then the mapping symbol for the
      following code will have the same value.  */
   if (value == 0)
     {
-       if (frag->tc_frag_data.first_map_symbol != NULL)
+      if (frag->tc_frag_data.first_map_symbol != NULL)
 	{
 	  know (S_GET_VALUE (frag->tc_frag_data.first_map_symbol)
 		== S_GET_VALUE (symbol));
 	  /* Remove the old one.  */
-	  symbol_remove (frag->tc_frag_data.first_map_symbol,
-			 &symbol_rootP, &symbol_lastP);
+	  remove_mapping_symbol (frag->tc_frag_data.first_map_symbol, symbol);
 	}
       frag->tc_frag_data.first_map_symbol = symbol;
     }
@@ -491,8 +524,7 @@ make_mapping_symbol (enum riscv_seg_mstate state,
       /* Remove the old one.  */
       if (S_GET_VALUE (frag->tc_frag_data.last_map_symbol)
 	  == S_GET_VALUE (symbol))
-	symbol_remove (frag->tc_frag_data.last_map_symbol,
-		       &symbol_rootP, &symbol_lastP);
+	remove_mapping_symbol (frag->tc_frag_data.last_map_symbol, symbol);
     }
   frag->tc_frag_data.last_map_symbol = symbol;
 }
@@ -514,9 +546,14 @@ riscv_mapping_state (enum riscv_seg_mstate to_state,
       || !subseg_text_p (now_seg))
     return;
 
+  if (to_state == MAP_INSN && updated_riscv_subsets)
+    to_state = MAP_INSN_ARCH;
+
   /* The mapping symbol should be emitted if not in the right
-     mapping state  */
-  if (from_state == to_state)
+     mapping state.  */
+  if ((from_state == MAP_DATA && to_state == MAP_DATA)
+      || (from_state == MAP_INSN && to_state == MAP_INSN)
+      || (from_state == MAP_INSN_ARCH && to_state == MAP_INSN))
     return;
 
   valueT value = (valueT) (frag_now_fix () - max_chars);
@@ -573,7 +610,7 @@ riscv_check_mapping_symbols (bfd *abfd ATTRIBUTE_UNUSED,
 	    {
 	      /* The last mapping symbol overlaps with another one
 		 which at the start of the next frag.  */
-	      symbol_remove (last, &symbol_rootP, &symbol_lastP);
+	      remove_mapping_symbol (last, NULL);
 	      break;
 	    }
 
@@ -581,7 +618,7 @@ riscv_check_mapping_symbols (bfd *abfd ATTRIBUTE_UNUSED,
 	    {
 	      /* The last mapping symbol is at the end of the section.  */
 	      know (next->fr_fix == 0 && next->fr_var == 0);
-	      symbol_remove (last, &symbol_rootP, &symbol_lastP);
+	      remove_mapping_symbol (last, NULL);
 	      break;
 	    }
 
@@ -3855,11 +3892,13 @@ s_riscv_option (int x ATTRIBUTE_UNUSED)
   if (strcmp (name, "rvc") == 0)
     {
       riscv_update_subset (&riscv_rps_as, "+c");
+      updated_riscv_subsets = true;
       riscv_set_rvc (true);
     }
   else if (strcmp (name, "norvc") == 0)
     {
       riscv_update_subset (&riscv_rps_as, "-c");
+      updated_riscv_subsets = true;
       riscv_set_rvc (false);
     }
   else if (strcmp (name, "pic") == 0)
@@ -3880,6 +3919,7 @@ s_riscv_option (int x ATTRIBUTE_UNUSED)
       if (ISSPACE (*name) && *name != '\0')
 	name++;
       riscv_update_subset (&riscv_rps_as, name);
+      updated_riscv_subsets = true;
 
       riscv_set_rvc (false);
       if (riscv_subset_supports (&riscv_rps_as, "c"))
@@ -3911,6 +3951,7 @@ s_riscv_option (int x ATTRIBUTE_UNUSED)
 	  riscv_opts = s->options;
 	  riscv_subsets = s->subset_list;
 	  riscv_rps_as.subset_list = riscv_subsets;
+	  updated_riscv_subsets = true;
 	  riscv_release_subset_list (release_subsets);
 	  free (s);
 	}
diff --git a/gas/testsuite/gas/riscv/mapping-01a.d b/gas/testsuite/gas/riscv/mapping-01a.d
index 32e0027..2aefe5a 100644
--- a/gas/testsuite/gas/riscv/mapping-01a.d
+++ b/gas/testsuite/gas/riscv/mapping-01a.d
@@ -8,7 +8,7 @@ SYMBOL TABLE:
 0+00 l    d  .text	0+00 .text
 0+00 l    d  .data	0+00 .data
 0+00 l    d  .bss	0+00 .bss
-0+00 l       .text	0+00 \$x
+0+00 l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+00 l    d  .foo	0+00 .foo
 0+00 l       .foo	0+00 foo
 0+00 l       .foo	0+00 \$x
diff --git a/gas/testsuite/gas/riscv/mapping-02a.d b/gas/testsuite/gas/riscv/mapping-02a.d
index 333f12c..155ae02 100644
--- a/gas/testsuite/gas/riscv/mapping-02a.d
+++ b/gas/testsuite/gas/riscv/mapping-02a.d
@@ -9,7 +9,7 @@ SYMBOL TABLE:
 0+00 l    d  .data	0+00 .data
 0+00 l    d  .bss	0+00 .bss
 0+00 l       .text	0+00 \$d
-0+04 l       .text	0+00 \$x
+0+04 l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+0c l       .text	0+00 \$d
 0+0e l       .text	0+00 \$x
 0+00 l    d  .riscv.attributes	0+00 .riscv.attributes
diff --git a/gas/testsuite/gas/riscv/mapping-03a.d b/gas/testsuite/gas/riscv/mapping-03a.d
index d3663b6..36646bf 100644
--- a/gas/testsuite/gas/riscv/mapping-03a.d
+++ b/gas/testsuite/gas/riscv/mapping-03a.d
@@ -8,7 +8,7 @@ SYMBOL TABLE:
 0+00 l    d  .text	0+00 .text
 0+00 l    d  .data	0+00 .data
 0+00 l    d  .bss	0+00 .bss
-0+00 l       .text	0+00 \$x
+0+00 l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+04 l       .text	0+00 \$d
 0+08 l       .text	0+00 \$x
 0+14 l       .text	0+00 \$d
diff --git a/gas/testsuite/gas/riscv/mapping-04a.d b/gas/testsuite/gas/riscv/mapping-04a.d
index 1ae9653..13d17bc 100644
--- a/gas/testsuite/gas/riscv/mapping-04a.d
+++ b/gas/testsuite/gas/riscv/mapping-04a.d
@@ -9,7 +9,7 @@ SYMBOL TABLE:
 0+00 l    d  .data	0+00 .data
 0+00 l    d  .bss	0+00 .bss
 0+00 l       .text	0+00 \$d
-0+0d l       .text	0+00 \$x
+0+0d l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+15 l       .text	0+00 \$d
 0+1f l       .text	0+00 \$x
 0+00 l    d  .riscv.attributes	0+00 .riscv.attributes
diff --git a/gas/testsuite/gas/riscv/mapping-norelax-03a.d b/gas/testsuite/gas/riscv/mapping-norelax-03a.d
index 916f732..dd92854 100644
--- a/gas/testsuite/gas/riscv/mapping-norelax-03a.d
+++ b/gas/testsuite/gas/riscv/mapping-norelax-03a.d
@@ -8,7 +8,7 @@ SYMBOL TABLE:
 0+00 l    d  .text	0+00 .text
 0+00 l    d  .data	0+00 .data
 0+00 l    d  .bss	0+00 .bss
-0+00 l       .text	0+00 \$x
+0+00 l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+04 l       .text	0+00 \$d
 0+08 l       .text	0+00 \$x
 0+10 l       .text	0+00 \$d
diff --git a/gas/testsuite/gas/riscv/mapping-norelax-04a.d b/gas/testsuite/gas/riscv/mapping-norelax-04a.d
index d552a7f..a22da2c 100644
--- a/gas/testsuite/gas/riscv/mapping-norelax-04a.d
+++ b/gas/testsuite/gas/riscv/mapping-norelax-04a.d
@@ -12,5 +12,5 @@ SYMBOL TABLE:
 0+14 l       .text	0+00 \$d
 0+1e l       .text	0+00 \$x
 0+0d l       .text	0+00 \$d
-0+0e l       .text	0+00 \$x
+0+0e l       .text	0+00 \$xrv64i2p1_m2p0_a2p1_f2p2_d2p2_zicsr2p0_zifencei2p0
 0+00 l    d  .riscv.attributes	0+00 .riscv.attributes
diff --git a/gas/testsuite/gas/riscv/option-arch-01a.d b/gas/testsuite/gas/riscv/option-arch-01a.d
index aed4ca8..1d14c60 100644
--- a/gas/testsuite/gas/riscv/option-arch-01a.d
+++ b/gas/testsuite/gas/riscv/option-arch-01a.d
@@ -10,5 +10,5 @@ Disassembly of section .text:
 0+000 <.text>:
 [ 	]+[0-9a-f]+:[  	]+952e[    	]+add[        	]+a0,a0,a1
 [ 	]+[0-9a-f]+:[  	]+00b50533[    	]+add[        	]+a0,a0,a1
-[ 	]+[0-9a-f]+:[  	]+00302573[    	]+csrr[        	]+a0,fcsr
+[ 	]+[0-9a-f]+:[  	]+00302573[    	]+frcsr[        	]+a0
 #...
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index b115e33..3721131 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -515,6 +515,7 @@ enum riscv_seg_mstate
   MAP_NONE = 0,		/* Must be zero, for seginfo in new sections.  */
   MAP_DATA,		/* Data.  */
   MAP_INSN,		/* Instructions.  */
+  MAP_INSN_ARCH,	/* Instructions with specific extensions.  */
 };
 
 extern const char * const riscv_gpr_names_numeric[NGPR];
diff --git a/opcodes/riscv-dis.c b/opcodes/riscv-dis.c
index 164fd20..e7eb641 100644
--- a/opcodes/riscv-dis.c
+++ b/opcodes/riscv-dis.c
@@ -640,6 +640,9 @@ riscv_disassemble_insn (bfd_vma memaddr, insn_t word, disassemble_info *info)
       /* If arch has ZFINX flags, use gpr for disassemble.  */
       if(riscv_subset_supports (&riscv_rps_dis, "zfinx"))
 	riscv_fpr_names = riscv_gpr_names;
+      else
+	riscv_fpr_names = riscv_gpr_names == riscv_gpr_names_abi ?
+			  riscv_fpr_names_abi : riscv_fpr_names_numeric;
 
       for (; op->name; op++)
 	{
@@ -750,7 +753,14 @@ riscv_get_map_state (int n,
     return false;
 
   name = bfd_asymbol_name(info->symtab[n]);
-  if (strcmp (name, "$x") == 0)
+  if (strncmp (name, "$xrv", 4) == 0)
+    {
+      *state = MAP_INSN_ARCH;
+
+      riscv_release_subset_list (&riscv_subsets);
+      riscv_parse_subset (&riscv_rps_dis, name + 2);
+    }
+  else if (strcmp (name, "$x") == 0)
     *state = MAP_INSN;
   else if (strcmp (name, "$d") == 0)
     *state = MAP_DATA;
-- 
2.7.4