[Tarantool-patches] [PATCH 6/7] fiber: refactor lua backtrace routine

eelchinov at tarantool.org eelchinov at tarantool.org
Thu Jul 1 23:24:44 MSK 2021


From: Egor Elchinov <eelchinov at tarantool.org>

From: Egor Elchinov <elchinov.es at gmail.com>

Lua backtrace with callback moved to new routine
`lua_backtrace_cb()` similar to the `backtrace_cb()`
for C backtrace.

Needed for: #4002
---
 src/lua/fiber.c | 165 +++++++++++++++++++++---------------------------
 1 file changed, 73 insertions(+), 92 deletions(-)

diff --git a/src/lua/fiber.c b/src/lua/fiber.c
index fe01ae23b..9e0c33a8f 100644
--- a/src/lua/fiber.c
+++ b/src/lua/fiber.c
@@ -205,14 +205,17 @@ struct lua_parent_tb_ctx {
 	int tb_frame;
 };
 
+/** Lua backtrace callback type */
+typedef int (lua_backtrace_cb)(struct lua_Debug *ar, int frame_no, void *cb_ctx);
+
 #if ENABLE_BACKTRACE
 static void
-dump_lua_frame(struct lua_State *L, lua_Debug *ar, int tb_frame)
+dump_lua_frame(struct lua_State *L, const char *name, const char *src, int line,
+	       int tb_frame)
 {
 	char buf[512];
 	snprintf(buf, sizeof(buf), "%s in %s at line %i",
-		 ar->name != NULL ? ar->name : "(unnamed)",
-		 ar->source, ar->currentline);
+		 name != NULL ? name : "(unnamed)", src, line);
 	lua_pushnumber(L, tb_frame);
 	lua_newtable(L);
 	lua_pushstring(L, "L");
@@ -221,20 +224,65 @@ dump_lua_frame(struct lua_State *L, lua_Debug *ar, int tb_frame)
 	lua_settable(L, -3);
 }
 
+static int
+dump_lua_frame_cb(lua_Debug *ar, int tb_frame, void *cb_ctx)
+{
+	(void) tb_frame;
+	struct lua_fiber_tb_ctx *tb_ctx = (struct lua_fiber_tb_ctx *)cb_ctx;
+
+	tb_ctx->tb_frame++;
+	dump_lua_frame(tb_ctx->L, ar->name, ar->source, ar->currentline,
+		       tb_ctx->tb_frame);
+
+	return 0;
+}
+
+static int
+save_lua_frame_cb(lua_Debug *ar, int tb_frame, void *cb_ctx)
+{
+	struct parent_bt_lua *bt = (struct parent_bt_lua *)cb_ctx;
+
+	if (tb_frame >= PARENT_BT_LUA_LEN_MAX)
+		return 1;
+
+	bt->cnt++;
+	bt->lines[tb_frame] = ar->currentline;
+	strncpy(bt->names[tb_frame], ar->name == NULL ? "(unnamed)" : ar->name,
+		PARENT_BT_LUA_NAME_MAX - 1);
+	strncpy(bt->sources[tb_frame], ar->source,
+		PARENT_BT_LUA_NAME_MAX - 1);
+
+	return 0;
+}
+
 static void
-dump_parent_lua_frame(struct lua_State *L, const char *name, const char *src,
-		      int currentline, int tb_frame)
+lua_backtrace_foreach(struct lua_State *L, lua_backtrace_cb cb, void *cb_ctx)
 {
-	char buf[512];
-	snprintf(buf, sizeof(buf), "%s in %s at line %i",
-		 name != NULL ? name : "(unnamed)",
-		 src, currentline);
-	lua_pushnumber(L, tb_frame);
-	lua_newtable(L);
-	lua_pushstring(L, "L");
-	lua_pushstring(L, buf);
-	lua_settable(L, -3);
-	lua_settable(L, -3);
+	int lua_frame = 0, tb_frame = 0;
+	lua_Debug ar;
+	while (lua_getstack(L, lua_frame, &ar) > 0) {
+		/* Skip all following C-frames. */
+		lua_getinfo(L, "Sln", &ar);
+		if (*ar.what != 'C')
+			break;
+		if (ar.name != NULL) {
+			/* Dump frame if it is a C built-in call. */
+			if (cb(&ar, tb_frame, cb_ctx) != 0)
+				return;
+			tb_frame++;
+		}
+		lua_frame++;
+	}
+	while (lua_getstack(L, lua_frame, &ar) > 0) {
+		/* Trace Lua frame. */
+		lua_getinfo(L, "Sln", &ar);
+		if (*ar.what == 'C')
+			break;
+		if (cb(&ar, tb_frame, cb_ctx) != 0)
+			return;
+		tb_frame++;
+		lua_frame++;
+	}
 }
 
 static int
@@ -247,31 +295,9 @@ fiber_backtrace_cb(int frameno, void *frameret, const char *func, size_t offset,
 	 * https://github.com/tarantool/tarantool/issues/5326
 	 * will not resolved, but is possible afterwards.
 	 */
-	if (func != NULL && strstr(func, "lj_BC_FUNCC") == func) {
+	if (func != NULL && tb_ctx->R && strstr(func, "lj_BC_FUNCC") == func) {
 		/* We are in the LUA vm. */
-		lua_Debug ar;
-		while (tb_ctx->R && lua_getstack(tb_ctx->R, tb_ctx->lua_frame, &ar) > 0) {
-			/* Skip all following C-frames. */
-			lua_getinfo(tb_ctx->R, "Sln", &ar);
-			if (*ar.what != 'C')
-				break;
-			if (ar.name != NULL) {
-				/* Dump frame if it is a C built-in call. */
-				tb_ctx->tb_frame++;
-				dump_lua_frame(L, &ar, tb_ctx->tb_frame);
-			}
-			tb_ctx->lua_frame++;
-		}
-		while (tb_ctx->R && lua_getstack(tb_ctx->R, tb_ctx->lua_frame, &ar) > 0) {
-			/* Trace Lua frame. */
-			lua_getinfo(tb_ctx->R, "Sln", &ar);
-			if (*ar.what == 'C') {
-				break;
-			}
-			tb_ctx->tb_frame++;
-			dump_lua_frame(L, &ar, tb_ctx->tb_frame);
-			tb_ctx->lua_frame++;
-		}
+		lua_backtrace_foreach(tb_ctx->R, dump_lua_frame_cb, tb_ctx);
 	}
 	char buf[512];
 	int l = snprintf(buf, sizeof(buf), "#%-2d %p in ", frameno, frameret);
@@ -306,10 +332,10 @@ fiber_parent_backtrace_cb(int frameno, void *frameret, const char *func,
 		/* We are in the LUA vm. */
 		while (lua_frame < bt->cnt) {
 			tb_ctx->tb_frame++;
-			dump_parent_lua_frame(L, bt->names[lua_frame],
-					      bt->sources[lua_frame],
-					      bt->lines[lua_frame],
-					      tb_ctx->tb_frame);
+			dump_lua_frame(L, bt->names[lua_frame],
+				       bt->sources[lua_frame],
+				       bt->lines[lua_frame],
+				       tb_ctx->tb_frame);
 			lua_frame++;
 		}
 	}
@@ -332,60 +358,15 @@ fiber_parent_backtrace_cb(int frameno, void *frameret, const char *func,
 static int
 fiber_parent_bt_init(struct fiber *f, struct lua_State *L)
 {
-	int lua_frame = 0, tb_frame = 0;
-	lua_Debug ar;
 	struct parent_bt_lua *bt = NULL;
-
-	bt = (struct parent_bt_lua *)malloc(sizeof(*bt));
+	bt = (struct parent_bt_lua *)calloc(1, sizeof(*bt));
 	if (bt == NULL){
-		diag_set(OutOfMemory, sizeof(*bt), "malloc", "bt");
+		diag_set(OutOfMemory, sizeof(*bt), "calloc", "bt");
 		return 1;
 	}
 
-	while (tb_frame < PARENT_BT_LUA_LEN_MAX &&
-	       lua_getstack(L, lua_frame, &ar) > 0) {
-		/* Skip all following C-frames. */
-		lua_getinfo(L, "Sln", &ar);
-		if (*ar.what != 'C')
-			break;
-		if (ar.name != NULL) {
-			/* Dump frame if it is a C built-in call. */
-			bt->lines[tb_frame] = ar.currentline;
-			memset(bt->names[tb_frame], 0,
-			       PARENT_BT_LUA_NAME_MAX);
-			strncpy(bt->names[tb_frame], ar.name,
-				PARENT_BT_LUA_NAME_MAX - 1);
-			memset(bt->sources[tb_frame], 0,
-			       PARENT_BT_LUA_NAME_MAX);
-			strncpy(bt->sources[tb_frame], ar.source,
-				PARENT_BT_LUA_NAME_MAX - 1);
-			tb_frame++;
-		}
-		lua_frame++;
-	}
-	while (tb_frame < PARENT_BT_LUA_LEN_MAX &&
-	       lua_getstack(L, lua_frame, &ar) > 0) {
-		/* Trace Lua frame. */
-		lua_getinfo(L, "Sln", &ar);
-		if (*ar.what == 'C')
-			break;
-		bt->lines[tb_frame] = ar.currentline;
-		memset(bt->names[tb_frame], 0, PARENT_BT_LUA_NAME_MAX);
-		if (ar.name != NULL) {
-			strncpy(bt->names[tb_frame], ar.name,
-				PARENT_BT_LUA_NAME_MAX - 1);
-		} else {
-			strncpy(bt->names[tb_frame], "(unnamed)",
-				PARENT_BT_LUA_NAME_MAX - 1);
-		}
-		memset(bt->sources[tb_frame], 0, PARENT_BT_LUA_NAME_MAX);
-		strncpy(bt->sources[tb_frame], ar.source,
-			PARENT_BT_LUA_NAME_MAX - 1);
-		tb_frame++;
-		lua_frame++;
-	}
-
-	bt->cnt = tb_frame;
+	bt->cnt = 0;
+	lua_backtrace_foreach(L, save_lua_frame_cb, bt);
 	f->storage.lua.parent_bt = bt;
 
 	return 0;
-- 
2.31.1



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