travis-ci: fix LTO and clang

Made fixes:

- Added CMAKE_EXTRA_PARAMS environment to docker's container
  runs to enable -DENABLE_LTO=ON/OFF cmake option.

- Added CC/CXX environment to docker's container runs to set
  clang for cmake. Also the additional environment variables
  {CC,CXX}_FOR_BUILD were postponed, because we didn't
  run cross-compilation at the moment, for more info check:

    https://docs.travis-ci.com/user/languages/cpp/#choosing-compilers-to-test-against

- Changed LTO docker's image to 'debian-buster' due to LTO needed
  higher versions of packages, check for more information commit:

    f9e28ce ('Add LTO support')

- Fixed sources to avoid of failures on builds by GCC with LTO:

1)  src/box/memtx_rtree.c: In function ‘mp_decode_rect’:
    src/box/memtx_rtree.c:86:24: error: ‘c’ may be used uninitialized
      in this function [-Werror=maybe-uninitialized]
        rect->coords[i * 2] = c;
                            ^
    src/box/memtx_rtree.c:74:10: note: ‘c’ was declared here
      coord_t c;
              ^

2)  src/box/sql/func.c: In function ‘quoteFunc’:
    src/box/sql/func.c:1103:3: error: ‘b’ may be used uninitialized
      in this function [-Werror=maybe-uninitialized]
       sql_result_text(context, sql_value_boolean(argv[0]) ?
       ^
    src/box/sql/vdbeapi.c:217:7: note: ‘b’ was declared here
      bool b;
           ^

3)  src/box/tuple_update.c: In function ‘update_read_ops’:
    src/box/tuple_update.c:1022:4: error: ‘field_no’ may be used
      uninitialized in this function [-Werror=maybe-uninitialized]
        diag_set(ClientError, ER_NO_SUCH_FIELD_NO, field_no);
        ^
    src/box/tuple_update.c:1014:11: note: ‘field_no’ was declared here
       int32_t field_no;
               ^

4)  src/httpc.c: In function ‘httpc_set_verbose’:
    src/httpc.c:267:2: error: call to ‘_curl_easy_setopt_err_long’
      declared with attribute warning: curl_easy_setopt expects a long
      argument for this option [-Werror]
      curl_easy_setopt(req->curl_request.easy, CURLOPT_VERBOSE, curl_verbose);
      ^

5)  src/lua/httpc.c: In function ‘luaT_httpc_request’:
    src/lua/httpc.c:128:64: error: ‘MEM[(int *)&parser + 20B]’ may be used
      uninitialized in this function [-Werror=maybe-uninitialized]
      lua_pushinteger(L, (parser.http_minor > 0) ? parser.http_minor: 0);
                                                                    ^
    src/lua/httpc.c:67:21: note: ‘MEM[(int *)&parser + 20B]’ was declared here
      struct http_parser parser;
                         ^
    src/lua/httpc.c:124:64: error: ‘MEM[(int *)&parser + 16B]’ may be used
      uninitialized in this function [-Werror=maybe-uninitialized]
      lua_pushinteger(L, (parser.http_major > 0) ? parser.http_major: 0);
                                                                    ^
    src/lua/httpc.c:67:21: note: ‘MEM[(int *)&parser + 16B]’ was declared here
      struct http_parser parser;
                         ^

Close #4215

.travis.mk

@@ -2,7 +2,7 @@
 # Travis CI rules
 #
 
-DOCKER_IMAGE:=packpack/packpack:debian-stretch
+DOCKER_IMAGE?=packpack/packpack:debian-stretch
 
 all: package
 
@@ -27,6 +27,9 @@ docker_%:
 		-e CCACHE_DIR=/cache/ccache \
 		-e COVERALLS_TOKEN=${COVERALLS_TOKEN} \
 		-e TRAVIS_JOB_ID=${TRAVIS_JOB_ID} \
+		-e CMAKE_EXTRA_PARAMS=${CMAKE_EXTRA_PARAMS} \
+		-e CC=${CC} \
+		-e CXX=${CXX} \
 		${DOCKER_IMAGE} \
 		make -f .travis.mk $(subst docker_,,$@)
 
@@ -37,7 +40,7 @@ deps_ubuntu:
 		libcurl4-openssl-dev libunwind-dev libicu-dev \
 		python python-pip python-setuptools python-dev \
 		python-msgpack python-yaml python-argparse python-six python-gevent \
-		lcov ruby
+		lcov ruby clang llvm llvm-dev
 
 test_ubuntu: deps_ubuntu
 	cmake . -DCMAKE_BUILD_TYPE=RelWithDebInfo -DENABLE_WERROR=ON ${CMAKE_EXTRA_PARAMS}

.travis.yml

@@ -37,10 +37,16 @@ jobs:
         if: branch = "master"
       # Special targets (only LTO for now).
       - name: "LTO build + test (Linux, gcc)"
-        env: TARGET=test CMAKE_EXTRA_PARAMS=-DENABLE_LTO=ON
+        env: >
+          TARGET=test
+          CMAKE_EXTRA_PARAMS=-DENABLE_LTO=ON
+          DOCKER_IMAGE=packpack/packpack:debian-buster
         if: branch = "master"
       - name: "LTO build + test (Linux, clang)"
-        env: TARGET=test CMAKE_EXTRA_PARAMS=-DENABLE_LTO=ON
+        env: >
+          TARGET=test
+          CMAKE_EXTRA_PARAMS=-DENABLE_LTO=ON
+          DOCKER_IMAGE=packpack/packpack:debian-buster
         if: branch = "master"
         compiler: clang
       - name: "LTO build + test (OS X Mojave 10.14)"

src/box/memtx_rtree.c

@@ -71,7 +71,7 @@ static inline int
 mp_decode_rect(struct rtree_rect *rect, unsigned dimension,
 	       const char *mp, unsigned count, const char *what)
 {
-	coord_t c;
+	coord_t c = 0;
 	if (count == dimension) { /* point */
 		for (unsigned i = 0; i < dimension; i++) {
 			if (mp_decode_num(&mp, i, &c) < 0)

src/box/sql/vdbeapi.c

@@ -206,31 +206,33 @@ sql_value_bytes(sql_value * pVal)
 double
 sql_value_double(sql_value * pVal)
 {
-	double v;
+	double v = 0.0;
 	sqlVdbeRealValue((Mem *) pVal, &v);
 	return v;
 }
 
 bool
 sql_value_boolean(sql_value *val)
 {
-	bool b;
-	mem_value_bool((struct Mem *) val, &b);
+	bool b = false;
+	int rc = mem_value_bool((struct Mem *) val, &b);
+	assert(rc == 0);
+	(void) rc;
 	return b;
 }
 
 int
 sql_value_int(sql_value * pVal)
 {
-	int64_t i;
+	int64_t i = 0;
 	sqlVdbeIntValue((Mem *) pVal, &i);
 	return (int)i;
 }
 
 sql_int64
 sql_value_int64(sql_value * pVal)
 {
-	int64_t i;
+	int64_t i = 0;
 	sqlVdbeIntValue((Mem *) pVal, &i);
 	return i;
 }

src/box/tuple_update.c

@@ -1011,7 +1011,7 @@ update_read_ops(struct tuple_update *update, const char *expr,
 				 "field id must be a number");
 			return -1;
 		}
-		int32_t field_no;
+		int32_t field_no = 0;
 		if (mp_read_i32(update->index_base, op, &expr, &field_no))
 			return -1;
 		if (field_no - update->index_base >= 0) {

src/httpc.c

@@ -267,7 +267,8 @@ httpc_set_low_speed_limit(struct httpc_request *req, long low_speed_limit)
 void
 httpc_set_verbose(struct httpc_request *req, bool curl_verbose)
 {
-	curl_easy_setopt(req->curl_request.easy, CURLOPT_VERBOSE, curl_verbose);
+	curl_easy_setopt(req->curl_request.easy, CURLOPT_VERBOSE,
+			 (long) curl_verbose);
 }
 
 void

src/lib/http_parser/http_parser.c

@@ -40,6 +40,16 @@
  * adaptation from nginx http parser module
  */
 
+void http_parser_create(struct http_parser *parser)
+{
+ parser->hdr_value_start = NULL;
+ parser->hdr_value_end = NULL;
+ parser->http_major = -1;
+ parser->http_minor = -1;
+ parser->hdr_name = NULL;
+ parser->hdr_name_idx = 0;
+}
+
 /**
  * Utility function used in headers parsing
  */

src/lib/http_parser/http_parser.h

@@ -49,7 +49,13 @@ struct http_parser {
 	int hdr_name_idx;
 };
 
-/*
+/**
+ * @brief Initialize an http parser.
+ * @param parser structure to initialize
+ */
+void http_parser_create(struct http_parser *parser);
+
+/**
  * @brief Parse line containing http header info
  * @param parser object
  * @param bufp pointer to buffer with data

src/lua/httpc.c

@@ -65,6 +65,7 @@ parse_headers(lua_State *L, char *buffer, size_t len,
 	      int max_header_name_len)
 {
 	struct http_parser parser;
+	http_parser_create(&parser);
 	parser.hdr_name = (char *) calloc(max_header_name_len, sizeof(char));
 	if (parser.hdr_name == NULL) {
 		diag_set(OutOfMemory, max_header_name_len * sizeof(char),