[PATCH 34/40] gdbstub: Add members to identify registers to GDBFeature

[Alex Bennée]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

These members will be used to help plugins to identify registers.
The added members in instances of GDBFeature dynamically generated by
CPUs will be filled in later changes.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20231213-gdb-v17-10-777047380591@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 include/exec/gdbstub.h  |  3 +++
 gdbstub/gdbstub.c       | 12 +++++++++---
 target/riscv/gdbstub.c  |  4 +---
 scripts/feature_to_c.py | 14 +++++++++++++-
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h
index 82a8afa237f..da9ddfe54c5 100644
--- a/include/exec/gdbstub.h
+++ b/include/exec/gdbstub.h
@@ -13,12 +13,15 @@
 typedef struct GDBFeature {
     const char *xmlname;
     const char *xml;
+    const char *name;
+    const char * const *regs;
     int num_regs;
 } GDBFeature;
 
 typedef struct GDBFeatureBuilder {
     GDBFeature *feature;
     GPtrArray *xml;
+    GPtrArray *regs;
     int base_reg;
 } GDBFeatureBuilder;
 
diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 801eba9a0b0..420ab2a3766 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -419,9 +419,10 @@ void gdb_feature_builder_init(GDBFeatureBuilder *builder, 
GDBFeature *feature,
     builder->feature = feature;
     builder->xml = g_ptr_array_new();
     g_ptr_array_add(builder->xml, header);
+    builder->regs = g_ptr_array_new();
     builder->base_reg = base_reg;
     feature->xmlname = xmlname;
-    feature->num_regs = 0;
+    feature->name = name;
 }
 
 void gdb_feature_builder_append_tag(const GDBFeatureBuilder *builder,
@@ -440,10 +441,12 @@ void gdb_feature_builder_append_reg(const 
GDBFeatureBuilder *builder,
                                     const char *type,
                                     const char *group)
 {
-    if (builder->feature->num_regs < regnum) {
-        builder->feature->num_regs = regnum;
+    if (builder->regs->len <= regnum) {
+        g_ptr_array_set_size(builder->regs, regnum + 1);
     }
 
+    builder->regs->pdata[regnum] = (gpointer *)name;
+
     if (group) {
         gdb_feature_builder_append_tag(
             builder,
@@ -469,6 +472,9 @@ void gdb_feature_builder_end(const GDBFeatureBuilder 
*builder)
     }
 
     g_ptr_array_free(builder->xml, TRUE);
+
+    builder->feature->num_regs = builder->regs->len;
+    builder->feature->regs = (void *)g_ptr_array_free(builder->regs, FALSE);
 }
 
 const GDBFeature *gdb_find_static_feature(const char *xmlname)
diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
index 68d0fdc1fd6..d9b52ffd09b 100644
--- a/target/riscv/gdbstub.c
+++ b/target/riscv/gdbstub.c
@@ -266,11 +266,9 @@ static GDBFeature *riscv_gen_dynamic_csr_feature(CPUState 
*cs, int base_reg)
         }
         predicate = csr_ops[i].predicate;
         if (predicate && (predicate(env, i) == RISCV_EXCP_NONE)) {
-            g_autofree char *dynamic_name = NULL;
             name = csr_ops[i].name;
             if (!name) {
-                dynamic_name = g_strdup_printf("csr%03x", i);
-                name = dynamic_name;
+                name = g_strdup_printf("csr%03x", i);
             }
 
             gdb_feature_builder_append_reg(&builder, name, bitsize, i,
diff --git a/scripts/feature_to_c.py b/scripts/feature_to_c.py
index e04d6b2df7f..807af0e685c 100644
--- a/scripts/feature_to_c.py
+++ b/scripts/feature_to_c.py
@@ -50,7 +50,9 @@ def writeliteral(indent, bytes):
         sys.stderr.write(f'unexpected start tag: {element.tag}\n')
         exit(1)
 
+    feature_name = element.attrib['name']
     regnum = 0
+    regnames = []
     regnums = []
     tags = ['feature']
     for event, element in events:
@@ -67,6 +69,7 @@ def writeliteral(indent, bytes):
                 if 'regnum' in element.attrib:
                     regnum = int(element.attrib['regnum'])
 
+                regnames.append(element.attrib['name'])
                 regnums.append(regnum)
                 regnum += 1
 
@@ -85,6 +88,15 @@ def writeliteral(indent, bytes):
     writeliteral(8, bytes(os.path.basename(input), 'utf-8'))
     sys.stdout.write(',\n')
     writeliteral(8, read)
-    sys.stdout.write(f',\n        {num_regs},\n    }},\n')
+    sys.stdout.write(',\n')
+    writeliteral(8, bytes(feature_name, 'utf-8'))
+    sys.stdout.write(',\n        (const char * const []) {\n')
+
+    for index, regname in enumerate(regnames):
+        sys.stdout.write(f'            [{regnums[index] - base_reg}] =\n')
+        writeliteral(16, bytes(regname, 'utf-8'))
+        sys.stdout.write(',\n')
+
+    sys.stdout.write(f'        }},\n        {num_regs},\n    }},\n')
 
 sys.stdout.write('    { NULL }\n};\n')
-- 
2.39.2