target/riscv: Use GDBFeature for dynamic XML

In preparation for a change to use GDBFeature as a parameter of
gdb_register_coprocessor(), convert the internal representation of
dynamic feature from plain XML to GDBFeature.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20231213-gdb-v17-3-777047380591@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240227144335.1196131-8-alex.bennee@linaro.org>

target/riscv/cpu.c

@@ -2305,9 +2305,9 @@ static const char *riscv_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
     RISCVCPU *cpu = RISCV_CPU(cs);
 
     if (strcmp(xmlname, "riscv-csr.xml") == 0) {
-        return cpu->dyn_csr_xml;
+        return cpu->dyn_csr_feature.xml;
     } else if (strcmp(xmlname, "riscv-vector.xml") == 0) {
-        return cpu->dyn_vreg_xml;
+        return cpu->dyn_vreg_feature.xml;
     }
 
     return NULL;

target/riscv/cpu.h

@@ -24,6 +24,7 @@
 #include "hw/registerfields.h"
 #include "hw/qdev-properties.h"
 #include "exec/cpu-defs.h"
+#include "exec/gdbstub.h"
 #include "qemu/cpu-float.h"
 #include "qom/object.h"
 #include "qemu/int128.h"
@@ -445,8 +446,8 @@ struct ArchCPU {
 
     CPURISCVState env;
 
-    char *dyn_csr_xml;
-    char *dyn_vreg_xml;
+    GDBFeature dyn_csr_feature;
+    GDBFeature dyn_vreg_feature;
 
     /* Configuration Settings */
     RISCVCPUConfig cfg;

target/riscv/gdbstub.c

@@ -214,14 +214,15 @@ static int riscv_gdb_set_virtual(CPURISCVState *cs, uint8_t *mem_buf, int n)
     return 0;
 }
 
-static int riscv_gen_dynamic_csr_xml(CPUState *cs, int base_reg)
+static GDBFeature *riscv_gen_dynamic_csr_feature(CPUState *cs, int base_reg)
 {
     RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(cs);
     RISCVCPU *cpu = RISCV_CPU(cs);
     CPURISCVState *env = &cpu->env;
-    GString *s = g_string_new(NULL);
+    GDBFeatureBuilder builder;
     riscv_csr_predicate_fn predicate;
     int bitsize = riscv_cpu_max_xlen(mcc);
+    const char *name;
     int i;
 
 #if !defined(CONFIG_USER_ONLY)
@@ -233,82 +234,74 @@ static int riscv_gen_dynamic_csr_xml(CPUState *cs, int base_reg)
         bitsize = 64;
     }
 
-    g_string_printf(s, "<?xml version=\"1.0\"?>");
-    g_string_append_printf(s, "<!DOCTYPE feature SYSTEM \"gdb-target.dtd\">");
-    g_string_append_printf(s, "<feature name=\"org.gnu.gdb.riscv.csr\">");
+    gdb_feature_builder_init(&builder, &cpu->dyn_csr_feature,
+                             "org.gnu.gdb.riscv.csr", "riscv-csr.xml",
+                             base_reg);
 
     for (i = 0; i < CSR_TABLE_SIZE; i++) {
         if (env->priv_ver < csr_ops[i].min_priv_ver) {
             continue;
         }
         predicate = csr_ops[i].predicate;
         if (predicate && (predicate(env, i) == RISCV_EXCP_NONE)) {
-            if (csr_ops[i].name) {
-                g_string_append_printf(s, "<reg name=\"%s\"", csr_ops[i].name);
-            } else {
-                g_string_append_printf(s, "<reg name=\"csr%03x\"", i);
+            g_autofree char *dynamic_name = NULL;
+            name = csr_ops[i].name;
+            if (!name) {
+                dynamic_name = g_strdup_printf("csr%03x", i);
+                name = dynamic_name;
             }
-            g_string_append_printf(s, " bitsize=\"%d\"", bitsize);
-            g_string_append_printf(s, " regnum=\"%d\"/>", base_reg + i);
+
+            gdb_feature_builder_append_reg(&builder, name, bitsize, i,
+                                           "int", NULL);
         }
     }
 
-    g_string_append_printf(s, "</feature>");
-
-    cpu->dyn_csr_xml = g_string_free(s, false);
+    gdb_feature_builder_end(&builder);
 
 #if !defined(CONFIG_USER_ONLY)
     env->debugger = false;
 #endif
 
-    return CSR_TABLE_SIZE;
+    return &cpu->dyn_csr_feature;
 }
 
-static int ricsv_gen_dynamic_vector_xml(CPUState *cs, int base_reg)
+static GDBFeature *ricsv_gen_dynamic_vector_feature(CPUState *cs, int base_reg)
 {
     RISCVCPU *cpu = RISCV_CPU(cs);
-    GString *s = g_string_new(NULL);
-    g_autoptr(GString) ts = g_string_new("");
-    int reg_width = cpu->cfg.vlenb << 3;
-    int num_regs = 0;
+    int reg_width = cpu->cfg.vlenb;
+    GDBFeatureBuilder builder;
     int i;
 
-    g_string_printf(s, "<?xml version=\"1.0\"?>");
-    g_string_append_printf(s, "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">");
-    g_string_append_printf(s, "<feature name=\"org.gnu.gdb.riscv.vector\">");
+    gdb_feature_builder_init(&builder, &cpu->dyn_vreg_feature,
+                             "org.gnu.gdb.riscv.vector", "riscv-vector.xml",
+                             base_reg);
 
     /* First define types and totals in a whole VL */
     for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
         int count = reg_width / vec_lanes[i].size;
-        g_string_printf(ts, "%s", vec_lanes[i].id);
-        g_string_append_printf(s,
-                               "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
-                               ts->str, vec_lanes[i].gdb_type, count);
+        gdb_feature_builder_append_tag(
+            &builder, "<vector id=\"%s\" type=\"%s\" count=\"%d\"/>",
+            vec_lanes[i].id, vec_lanes[i].gdb_type, count);
     }
 
     /* Define unions */
-    g_string_append_printf(s, "<union id=\"riscv_vector\">");
+    gdb_feature_builder_append_tag(&builder, "<union id=\"riscv_vector\">");
     for (i = 0; i < ARRAY_SIZE(vec_lanes); i++) {
-        g_string_append_printf(s, "<field name=\"%c\" type=\"%s\"/>",
-                               vec_lanes[i].suffix,
-                               vec_lanes[i].id);
+        gdb_feature_builder_append_tag(&builder,
+                                       "<field name=\"%c\" type=\"%s\"/>",
+                                       vec_lanes[i].suffix, vec_lanes[i].id);
     }
-    g_string_append(s, "</union>");
+    gdb_feature_builder_append_tag(&builder, "</union>");
 
     /* Define vector registers */
     for (i = 0; i < 32; i++) {
-        g_string_append_printf(s,
-                               "<reg name=\"v%d\" bitsize=\"%d\""
-                               " regnum=\"%d\" group=\"vector\""
-                               " type=\"riscv_vector\"/>",
-                               i, reg_width, base_reg++);
-        num_regs++;
+        gdb_feature_builder_append_reg(&builder, g_strdup_printf("v%d", i),
+                                       reg_width, i, "riscv_vector", "vector");
     }
 
-    g_string_append_printf(s, "</feature>");
+    gdb_feature_builder_end(&builder);
 
-    cpu->dyn_vreg_xml = g_string_free(s, false);
-    return num_regs;
+    return &cpu->dyn_vreg_feature;
 }
 
 void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
@@ -324,10 +317,9 @@ void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
                                  32, "riscv-32bit-fpu.xml", 0);
     }
     if (env->misa_ext & RVV) {
-        int base_reg = cs->gdb_num_regs;
         gdb_register_coprocessor(cs, riscv_gdb_get_vector,
                                  riscv_gdb_set_vector,
-                                 ricsv_gen_dynamic_vector_xml(cs, base_reg),
+                                 ricsv_gen_dynamic_vector_feature(cs, cs->gdb_num_regs)->num_regs,
                                  "riscv-vector.xml", 0);
     }
     switch (mcc->misa_mxl_max) {
@@ -347,9 +339,8 @@ void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
     }
 
     if (cpu->cfg.ext_zicsr) {
-        int base_reg = cs->gdb_num_regs;
         gdb_register_coprocessor(cs, riscv_gdb_get_csr, riscv_gdb_set_csr,
-                                 riscv_gen_dynamic_csr_xml(cs, base_reg),
+                                 riscv_gen_dynamic_csr_feature(cs, cs->gdb_num_regs)->num_regs,
                                  "riscv-csr.xml", 0);
     }
 }