[binutils-gdb] gas/RISC-V: adjust assembler for opcode table re-ordering

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f56532cc17868e2c7e765bfd78322157048ff6ec

commit f56532cc17868e2c7e765bfd78322157048ff6ec
Author: Jan Beulich <jbeulich@suse.com>
Date:   Wed Jan 11 10:31:43 2023 +0100

    gas/RISC-V: adjust assembler for opcode table re-ordering
    
    PR gas/29940
    
    With the single-operand JAL entry now sitting ahead of the two-operand
    one, the parsing of a two-operand insn would first try to parse an 'a'-
    style operand, resulting in the insertion of bogus (and otherwise
    unused) undefined symbols in the symbol table, having register names.
    Since 'a' is used as 1st operand only with J and JAL, and since JAL is
    the only insn _also_ allowing for a register as 1st operand (and then
    there being a 2nd one), special case this parsing aspect right there.
    
    Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>

Diff:
---
 gas/config/tc-riscv.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 2dc41768ce3..6793b6448b3 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -3266,6 +3266,17 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	      continue;
 
 	    case 'a': /* 20-bit PC-relative offset.  */
+	      /* Like in my_getSmallExpression() we need to avoid emitting
+		 a stray undefined symbol if the 1st JAL entry doesn't match,
+		 but the 2nd (with 2 operands) might.  */
+	      if (oparg == insn->args)
+		{
+		  asargStart = asarg;
+		  if (reg_lookup (&asarg, RCLASS_GPR, NULL)
+		      && (*asarg == ',' || (ISSPACE (*asarg) && asarg[1] == ',')))
+		    break;
+		  asarg = asargStart;
+		}
 	    jump:
 	      my_getExpression (imm_expr, asarg);
 	      asarg = expr_end;