[PATCH v2 2/5] gdb/aarch64: Add record support for MOPS instructions.

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

There are two kinds of MOPS instructions: set instructions and copy
instructions.  Within each group there are variants with minor
differences in how they read or write to memory — e.g., non-temporal
read and/or write, unprivileged read and/or write and permutations of
those — but they work in the same way in terms of the registers and
regions of memory that they modify.

PR tdep/31666
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31666
---
 gdb/aarch64-tdep.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

No change in v2.

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index e920cea49066..c60c5d6e0ec2 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -5289,6 +5289,86 @@ aarch64_record_asimd_load_store (aarch64_insn_decode_record *aarch64_insn_r)
   return AARCH64_RECORD_SUCCESS;
 }
 
+/* Record handler for Memory Copy and Memory Set instructions.  */
+
+static unsigned int
+aarch64_record_memcopy_memset (aarch64_insn_decode_record *aarch64_insn_r)
+{
+  if (record_debug)
+    debug_printf ("Process record: memory copy and memory set\n");
+
+  uint8_t op1 = bits (aarch64_insn_r->aarch64_insn, 22, 23);
+  uint8_t op2 = bits (aarch64_insn_r->aarch64_insn, 12, 15);
+  uint32_t reg_rd = bits (aarch64_insn_r->aarch64_insn, 0, 4);
+  uint32_t reg_rn = bits (aarch64_insn_r->aarch64_insn, 5, 9);
+  uint32_t record_buf[3];
+  uint64_t record_buf_mem[4];
+
+  if (op1 != 3)
+    {
+      /* Copy instructions.  */
+      uint32_t reg_rs = bits (aarch64_insn_r->aarch64_insn, 16, 20);
+
+      record_buf[0] = reg_rd;
+      record_buf[1] = reg_rn;
+      record_buf[2] = reg_rs;
+      aarch64_insn_r->reg_rec_count = 3;
+
+      ULONGEST dest_addr;
+      regcache_raw_read_unsigned (aarch64_insn_r->regcache, reg_rd,
+				  &dest_addr);
+      ULONGEST source_addr;
+      regcache_raw_read_unsigned (aarch64_insn_r->regcache, reg_rs,
+				  &source_addr);
+      LONGEST length;
+      regcache_raw_read_signed (aarch64_insn_r->regcache, reg_rn,
+				&length);
+
+      /* In a processor using algorithm option A, the length in Rn has an
+	 inverted sign.  */
+      if (length < 0)
+	length *= -1;
+
+      record_buf_mem[0] = length;
+      record_buf_mem[1] = dest_addr;
+      record_buf_mem[2] = length;
+      record_buf_mem[3] = source_addr;
+      aarch64_insn_r->mem_rec_count = 2;
+    }
+  else if ((op1 == 3 && op2 < 12) || (op1 == 3 && op2 < 12))
+    {
+      /* Set instructions.  */
+      record_buf[0] = reg_rd;
+      record_buf[1] = reg_rn;
+      aarch64_insn_r->reg_rec_count = 2;
+
+      ULONGEST address;
+      regcache_raw_read_unsigned (aarch64_insn_r->regcache, reg_rd,
+				  &address);
+
+      LONGEST length;
+      regcache_raw_read_signed (aarch64_insn_r->regcache, reg_rn,
+				&length);
+
+      /* In a processor using algorithm option B, the length in Rn has an
+	 inverted sign.  */
+      if (length < 0)
+	length *= -1;
+
+      record_buf_mem[0] = length;
+      record_buf_mem[1] = address;
+      aarch64_insn_r->mem_rec_count = 1;
+    }
+  else
+    return AARCH64_RECORD_UNKNOWN;
+
+  MEM_ALLOC (aarch64_insn_r->aarch64_mems, aarch64_insn_r->mem_rec_count,
+	     record_buf_mem);
+  REG_ALLOC (aarch64_insn_r->aarch64_regs, aarch64_insn_r->reg_rec_count,
+	     record_buf);
+  return AARCH64_RECORD_SUCCESS;
+}
+
 /* Record handler for load and store instructions.  */
 
 static unsigned int
@@ -5566,6 +5646,10 @@ aarch64_record_load_store (aarch64_insn_decode_record *aarch64_insn_r)
       if (insn_bits10_11 == 0x01 || insn_bits10_11 == 0x03)
 	record_buf[aarch64_insn_r->reg_rec_count++] = reg_rn;
     }
+  /* Memory Copy and Memory Set instructions.  */
+  else if ((insn_bits24_27 & 1) == 1 && insn_bits28_29 == 1
+	   && insn_bits10_11 == 1 && !insn_bit21)
+    return aarch64_record_memcopy_memset (aarch64_insn_r);
   /* Advanced SIMD load/store instructions.  */
   else
     return aarch64_record_asimd_load_store (aarch64_insn_r);