[binutils-gdb] gdb/riscv: Partial support for instructions up to 176-bit

[Tsukasa OI <a4lg@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=436a7b5ef27e6d866a631d6020e904321cbee7e8

commit 436a7b5ef27e6d866a631d6020e904321cbee7e8
Author: Tsukasa OI <research_trasio@irq.a4lg.com>
Date:   Tue Oct 4 08:42:35 2022 +0000

    gdb/riscv: Partial support for instructions up to 176-bit
    
    Because riscv_insn_length started to support instructions up to 176-bit,
    we need to increase buf size to 176-bit in size.
    
    Also, that would break an assumption in riscv_insn::decode so this commit
    fixes it, noting that instructions longer than 64-bit are not fully
    supported yet.

Diff:
---
 gdb/riscv-tdep.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index 47d8f9e601b..63ebed4ff19 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -1770,7 +1770,7 @@ riscv_insn::fetch_instruction (struct gdbarch *gdbarch,
 			       CORE_ADDR addr, int *len)
 {
   enum bfd_endian byte_order = gdbarch_byte_order_for_code (gdbarch);
-  gdb_byte buf[8];
+  gdb_byte buf[RISCV_MAX_INSN_LEN];
   int instlen, status;
 
   /* All insns are at least 16 bits.  */
@@ -1933,9 +1933,10 @@ riscv_insn::decode (struct gdbarch *gdbarch, CORE_ADDR pc)
     }
   else
     {
-      /* This must be a 6 or 8 byte instruction, we don't currently decode
-	 any of these, so just ignore it.  */
-      gdb_assert (m_length == 6 || m_length == 8);
+      /* 6 bytes or more.  If the instruction is longer than 8 bytes, we don't
+	 have full instruction bits in ival.  At least, such long instructions
+	 are not defined yet, so just ignore it.  */
+      gdb_assert (m_length > 0 && m_length % 2 == 0);
       m_opcode = OTHER;
     }
 }