From b5964191f0d2fc3ace607af001df3d57cbfbaf2b Mon Sep 17 00:00:00 2001
From: Steven Stallion <stallion@squareup.com>
Date: Mon, 1 May 2017 14:38:35 -0500
Subject: [PATCH] register: support non-existent registers

This patch fixes a number of bugs caused by incomplete support for
non-existent registers. This is needed for targets that provide optional
registers or non-linear register numbers.

Change-Id: I216196e0051f28887a2c3da410959382369eed80
Signed-off-by: Steven Stallion <stallion@squareup.com>
Reviewed-on: http://openocd.zylin.com/4113
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>
---
 src/server/gdb_server.c |  7 ++++++-
 src/target/register.c   |  4 ++++
 src/target/target.c     | 15 +++++++++++----
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c
index a45127360..ee9fc1c97 100644
--- a/src/server/gdb_server.c
+++ b/src/server/gdb_server.c
@@ -1179,8 +1179,11 @@ static int gdb_get_registers_packet(struct connection *connection,
 	if (retval != ERROR_OK)
 		return gdb_error(connection, retval);
 
-	for (i = 0; i < reg_list_size; i++)
+	for (i = 0; i < reg_list_size; i++) {
+		if (reg_list[i] == NULL || reg_list[i]->exist == false)
+			continue;
 		reg_packet_size += DIV_ROUND_UP(reg_list[i]->size, 8) * 2;
+	}
 
 	assert(reg_packet_size > 0);
 
@@ -1191,6 +1194,8 @@ static int gdb_get_registers_packet(struct connection *connection,
 	reg_packet_p = reg_packet;
 
 	for (i = 0; i < reg_list_size; i++) {
+		if (reg_list[i] == NULL || reg_list[i]->exist == false)
+			continue;
 		if (!reg_list[i]->valid) {
 			retval = reg_list[i]->type->get(reg_list[i]);
 			if (retval != ERROR_OK && gdb_report_register_access_error) {
diff --git a/src/target/register.c b/src/target/register.c
index 1d63e12f7..850641448 100644
--- a/src/target/register.c
+++ b/src/target/register.c
@@ -44,6 +44,8 @@ struct reg *register_get_by_name(struct reg_cache *first,
 
 	while (cache) {
 		for (i = 0; i < cache->num_regs; i++) {
+			if (cache->reg_list[i].exist == false)
+				continue;
 			if (strcmp(cache->reg_list[i].name, name) == 0)
 				return &(cache->reg_list[i]);
 		}
@@ -84,6 +86,8 @@ void register_cache_invalidate(struct reg_cache *cache)
 	struct reg *reg = cache->reg_list;
 
 	for (unsigned n = cache->num_regs; n != 0; n--, reg++) {
+		if (reg->exist == false)
+			continue;
 		reg->valid = 0;
 		reg->dirty = 0;
 	}
diff --git a/src/target/target.c b/src/target/target.c
index 478c39d1b..3aaebcd49 100644
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -2804,6 +2804,8 @@ COMMAND_HANDLER(handle_reg_command)
 			for (i = 0, reg = cache->reg_list;
 					i < cache->num_regs;
 					i++, reg++, count++) {
+				if (reg->exist == false)
+					continue;
 				/* only print cached values if they are valid */
 				if (reg->valid) {
 					value = buf_to_str(reg->value,
@@ -2857,14 +2859,15 @@ COMMAND_HANDLER(handle_reg_command)
 		/* access a single register by its name */
 		reg = register_get_by_name(target->reg_cache, CMD_ARGV[0], 1);
 
-		if (!reg) {
-			command_print(CMD_CTX, "register %s not found in current target", CMD_ARGV[0]);
-			return ERROR_OK;
-		}
+		if (!reg)
+			goto not_found;
 	}
 
 	assert(reg != NULL); /* give clang a hint that we *know* reg is != NULL here */
 
+	if (!reg->exist)
+		goto not_found;
+
 	/* display a register */
 	if ((CMD_ARGC == 1) || ((CMD_ARGC == 2) && !((CMD_ARGV[1][0] >= '0')
 			&& (CMD_ARGV[1][0] <= '9')))) {
@@ -2898,6 +2901,10 @@ COMMAND_HANDLER(handle_reg_command)
 	}
 
 	return ERROR_COMMAND_SYNTAX_ERROR;
+
+not_found:
+	command_print(CMD_CTX, "register %s not found in current target", CMD_ARGV[0]);
+	return ERROR_OK;
 }
 
 COMMAND_HANDLER(handle_poll_command)