[PATCH v2 2/2] contrib/plugins: add a drcov plugin

[NDNF]

This patch adds the ability to generate files in drcov format.
Primary goal this script is to have coverage
logfiles thatwork in Lighthouse.

Signed-off-by: Ivanov Arkady <arkadiy.ivanov@ispras.ru>
---
 contrib/plugins/Makefile |    1 
 contrib/plugins/drcov.c  |  148 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 contrib/plugins/drcov.c

diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile
index 7801b08b0d..0a681efeec 100644
--- a/contrib/plugins/Makefile
+++ b/contrib/plugins/Makefile
@@ -17,6 +17,7 @@ NAMES += hotblocks
 NAMES += hotpages
 NAMES += howvec
 NAMES += lockstep
+NAMES += drcov
 
 SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES)))
 
diff --git a/contrib/plugins/drcov.c b/contrib/plugins/drcov.c
new file mode 100644
index 0000000000..f94b52ff64
--- /dev/null
+++ b/contrib/plugins/drcov.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2021, Ivanov Arkady <arkadiy.ivanov@ispras.ru>
+ *
+ * Drcov - a DynamoRIO-based tool that collects coverage information
+ * from a binary. Primary goal this script is to have coverage log
+ * files that work in Lighthouse.
+ *
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ */
+
+#include <inttypes.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <glib.h>
+
+#include <qemu-plugin.h>
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+
+static char header[] = "DRCOV VERSION: 2\n"
+                "DRCOV FLAVOR: drcov-64\n"
+                "Module Table: version 2, count 1\n"
+                "Columns: id, base, end, entry, path\n";
+
+static FILE *fp;
+static char *file_name;
+static GMutex lock;
+
+typedef struct {
+    uint32_t start;
+    uint16_t size;
+    uint16_t mod_id;
+} bb_entry_t;
+
+static GSList *bbs;
+
+static void printf_header(void)
+{
+    g_autoptr(GString) head = g_string_new(header);
+    const char *path = qemu_plugin_path_to_binary();
+    uint64_t start_code = qemu_plugin_start_code();
+    uint64_t end_code = qemu_plugin_end_code();
+    uint64_t entry = qemu_plugin_entry_code();
+    g_string_append_printf(head, "0, 0x%lx, 0x%lx, 0x%lx, %s\n",
+                           start_code, end_code, entry, path);
+    g_string_append_printf(head, "BB Table: %d bbs\n", g_slist_length(bbs));
+    fwrite(head->str, sizeof(char), head->len, fp);
+}
+
+static void printf_char_array32(uint32_t data)
+{
+    const uint8_t *bytes = (const uint8_t *)(&data);
+    fwrite(bytes, sizeof(char), sizeof(data), fp);
+}
+
+static void printf_char_array16(uint16_t data)
+{
+    const uint8_t *bytes = (const uint8_t *)(&data);
+    fwrite(bytes, sizeof(char), sizeof(data), fp);
+}
+
+
+static void printf_el(gpointer data, gpointer user_data)
+{
+    g_mutex_lock(&lock);
+
+    bb_entry_t *bb = (bb_entry_t *)data;
+    printf_char_array32(bb->start);
+    printf_char_array16(bb->size);
+    printf_char_array16(bb->mod_id);
+
+    g_mutex_unlock(&lock);
+}
+
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+    /* Print function */
+    printf_header();
+    g_slist_foreach(bbs, printf_el, NULL);
+
+    /* Clear */
+    g_slist_free_full(bbs, &g_free);
+    g_free(file_name);
+    fclose(fp);
+}
+
+static void plugin_init(void)
+{
+    fp = fopen(file_name, "wb");
+}
+
+static void vcpu_tb_exec(unsigned int cpu_index, void *udata)
+{
+    bb_entry_t *bb = g_malloc0(sizeof(bb_entry_t));
+    memcpy(bb, udata, sizeof(bb_entry_t));
+
+    g_mutex_lock(&lock);
+    bbs = g_slist_append(bbs, bb);
+    g_mutex_unlock(&lock);
+}
+
+static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
+{
+    bb_entry_t *bb = g_new0(bb_entry_t, 1);
+    uint64_t pc = qemu_plugin_tb_vaddr(tb);
+
+    size_t n = qemu_plugin_tb_n_insns(tb);
+    for (int i = 0; i < n; i++) {
+        bb->size += qemu_plugin_insn_size(qemu_plugin_tb_get_insn(tb, i));
+    }
+
+    bb->start = pc;
+    bb->mod_id = 0;
+
+    qemu_plugin_register_vcpu_tb_exec_cb(tb, vcpu_tb_exec,
+                                         QEMU_PLUGIN_CB_NO_REGS,
+                                         (void *)bb);
+
+}
+
+QEMU_PLUGIN_EXPORT
+int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
+                        int argc, char **argv)
+{
+
+    if (!argc) {
+        file_name = "file.drcov.trace";
+    } else {
+        if (g_str_has_prefix(argv[0], "filename=")) {
+            size_t size = strlen(argv[0]) - 9;
+            file_name = g_malloc0(size + 1);
+            strncpy(file_name, argv[0] + 9, size);
+            file_name[size] = '\0';
+        }
+    }
+
+    plugin_init();
+
+    qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+    qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
+
+    return 0;
+}