[RFC,v3,06/34] Hexagon (disas) disassembler

Commit Message

Taylor Simpson Aug. 18, 2020, 3:50 p.m. UTC

The Hexagon disassembler calls disassemble_hexagon to decode a packet
and format it for printing

Signed-off-by: Taylor Simpson <[e-mail]>
---
 include/disas/dis-asm.h |  1 +
 disas/hexagon.c         | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 disas/Makefile.objs     |  1 +
 3 files changed, 64 insertions(+)
 create mode 100644 disas/hexagon.c

Comments

Richard Henderson Aug. 26, 2020, 1:52 p.m. UTC | #1

On 8/18/20 8:50 AM, Taylor Simpson wrote:
> +    len = disassemble_hexagon(words, i, buf, PACKET_BUFFER_LEN);
> +    slen = strlen(buf);
> +    if (buf[slen - 1] == '\n') {
> +        buf[slen - 1] = '\0';
> +    }
> +    (*info->fprintf_func)(info->stream, "%s", buf);

Normally our disassemblers print the instruction address; sometimes the raw
bytes (or word) of the instruction.

Looking forward to patch 14 where disassemble_hexagon is defined, I see none of
that.  Indeed, if disassembly fails, we get...

> +    if (decode_this(nwords, words, &pkt)) {
> +        snprint_a_pkt(buf, bufsize, &pkt);
> +        return pkt.encod_pkt_size_in_bytes;
> +    } else {
> +        snprintf(buf, bufsize, "<invalid>");
> +        return 0;
> +    }

... no indication at all what happened or where, just "<invalid>".  That's not
going to make it easy to find problems.


r~

Taylor Simpson Aug. 26, 2020, 11:52 p.m. UTC | #2

> -----Original Message-----
> From: Richard Henderson <[e-mail]>
> Sent: Wednesday, August 26, 2020 7:52 AM
> To: Taylor Simpson <[e-mail]>; [e-mail]
> Cc: [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]
> Subject: Re: [RFC PATCH v3 06/34] Hexagon (disas) disassembler
>
> Normally our disassemblers print the instruction address; sometimes the raw
> bytes (or word) of the instruction.

OK

Patch

diff --git a/include/disas/dis-asm.h b/include/disas/dis-asm.h
index 9856bf7..14ff2be 100644
--- a/include/disas/dis-asm.h
+++ b/include/disas/dis-asm.h
@@ -460,6 +460,7 @@  int print_insn_xtensa           (bfd_vma, disassemble_info*);
 int print_insn_riscv32          (bfd_vma, disassemble_info*);
 int print_insn_riscv64          (bfd_vma, disassemble_info*);
 int print_insn_rx(bfd_vma, disassemble_info *);
+int print_insn_hexagon(bfd_vma, disassemble_info *);
 
 #if 0
 /* Fetch the disassembler for a given BFD, if that support is available.  */
diff --git a/disas/hexagon.c b/disas/hexagon.c
new file mode 100644
index 0000000..6ee8653
--- /dev/null
+++ b/disas/hexagon.c
@@ -0,0 +1,62 @@ 
+/*
+ *  Copyright(c) 2019-2020 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * QEMU Hexagon Disassembler
+ */
+
+#include "qemu/osdep.h"
+#include "disas/dis-asm.h"
+#include "target/hexagon/cpu_bits.h"
+
+/*
+ * We will disassemble a packet with up to 4 instructions, so we need
+ * a hefty size buffer.
+ */
+#define PACKET_BUFFER_LEN                   1028
+
+int print_insn_hexagon(bfd_vma memaddr, struct disassemble_info *info)
+{
+    uint32_t words[PACKET_WORDS_MAX];
+    int len, slen;
+    char buf[PACKET_BUFFER_LEN];
+    int status;
+    int i;
+
+    for (i = 0; i < PACKET_WORDS_MAX; i++) {
+        status = (*info->read_memory_func)(memaddr + i * sizeof(uint32_t),
+                                           (bfd_byte *)&words[i],
+                                           sizeof(uint32_t), info);
+        if (status) {
+            if (i > 0) {
+                break;
+            }
+            (*info->memory_error_func)(status, memaddr, info);
+            return status;
+        }
+    }
+
+    len = disassemble_hexagon(words, i, buf, PACKET_BUFFER_LEN);
+    slen = strlen(buf);
+    if (buf[slen - 1] == '\n') {
+        buf[slen - 1] = '\0';
+    }
+    (*info->fprintf_func)(info->stream, "%s", buf);
+
+    return len;
+}
+
diff --git a/disas/Makefile.objs b/disas/Makefile.objs
index 3c1cdce..0e86964 100644
--- a/disas/Makefile.objs
+++ b/disas/Makefile.objs
@@ -24,6 +24,7 @@  common-obj-$(CONFIG_SH4_DIS) += sh4.o
 common-obj-$(CONFIG_SPARC_DIS) += sparc.o
 common-obj-$(CONFIG_LM32_DIS) += lm32.o
 common-obj-$(CONFIG_XTENSA_DIS) += xtensa.o
+common-obj-$(CONFIG_HEXAGON_DIS) += hexagon.o
 
 # TODO: As long as the TCG interpreter and its generated code depend
 # on the QEMU target, we cannot compile the disassembler here.