[binutils-gdb] x86: change type of Dwarf2 register numbers in register table

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=066673f6d5ef258b9534f6baaa3d52fa35905b00

commit 066673f6d5ef258b9534f6baaa3d52fa35905b00
Author: Jan Beulich <jbeulich@suse.com>
Date:   Fri Feb 9 08:38:04 2024 +0100

    x86: change type of Dwarf2 register numbers in register table
    
    Already the %bnd<N> registers used numbers beyond 127, and eGPR ones are
    all out of reach for "signed char", at least when CHAR_BITS=8. Switch to
    "unsigned char", covering appropriately in places where the value
    returned for "none" actually matters (in tc_x86_parse_to_dw2regnum()
    this is actually achieved by altering how X_op is set).

Diff:
---
 gas/config/tc-i386.c | 14 ++++++--------
 opcodes/i386-opc.h   |  4 ++--
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 9e7bb1dd4d6..925986f7fce 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -5396,10 +5396,8 @@ ginsn_opsize_prefix_p (void)
 static unsigned int
 ginsn_dw2_regnum (const reg_entry *ireg)
 {
-  /* PS: Note the data type here as int32_t, because of Dw2Inval (-1).  */
-  int32_t dwarf_reg = Dw2Inval;
   const reg_entry *temp = ireg;
-  unsigned int idx = 0;
+  unsigned int dwarf_reg = Dw2Inval, idx = 0;
 
   /* ginsn creation is available for AMD64 abi only ATM.  Other flag_code
      are not expected.  */
@@ -5442,9 +5440,9 @@ ginsn_dw2_regnum (const reg_entry *ireg)
 
   /* Sanity check - failure may indicate state corruption, bad ginsn or
      perhaps the i386-reg table and the current function got out of sync.  */
-  gas_assert (dwarf_reg >= 0);
+  gas_assert (dwarf_reg < Dw2Inval);
 
-  return (unsigned int) dwarf_reg;
+  return dwarf_reg;
 }
 
 static ginsnS *
@@ -17546,14 +17544,14 @@ tc_x86_parse_to_dw2regnum (expressionS *exp)
 
   if (exp->X_op == O_register && exp->X_add_number >= 0)
     {
+      exp->X_op = O_illegal;
       if ((addressT) exp->X_add_number < i386_regtab_size)
 	{
-	  exp->X_op = O_constant;
 	  exp->X_add_number = i386_regtab[exp->X_add_number]
 			      .dw2_regnum[flag_code >> 1];
+	  if (exp->X_add_number != Dw2Inval)
+	    exp->X_op = O_constant;
 	}
-      else
-	exp->X_op = O_illegal;
     }
 }
 
diff --git a/opcodes/i386-opc.h b/opcodes/i386-opc.h
index 004d9ee61fc..0a2c44a9d64 100644
--- a/opcodes/i386-opc.h
+++ b/opcodes/i386-opc.h
@@ -1051,7 +1051,7 @@ typedef struct
 #define RegIZ	(RegIP - 1)
 /* FLAT is a fake segment register (Intel mode).  */
 #define RegFlat     ((unsigned char) ~0)
-  signed char dw2_regnum[2];
-#define Dw2Inval (-1)
+  unsigned char dw2_regnum[2];
+#define Dw2Inval 0xff
 }
 reg_entry;