`ctf` plugin: Use CTF_SCOPE_PACKET_UNKNOWN in place of -1

Seen on clang-3.9, 4.0 and clang-1001.0.46.4.

  Comparison of constant -1 with expression of type 'enum *****'
  is always false [-Wtautological-constant-out-of-range-compare]

Note that the enum underlying type is implementation defined and left to
the choice of the compiler by the standard [1] (6.7.2.2 4). Most
compiler default to unsigned int. The use of -1 is not a problem per see
since wrap around of unsigned int behaviour is not undefined. Using -1
is the equivalent of assigning UINT_MAX here. This warning was removed
for later clang for these specific cases since the effect of always being
false is erroneous.

Still, it make more sense to use a specific enum for such case instead
of relying on the compiler type.

get_root_scope_from_absolute_pathstr depends on the fact that
CTF_SCOPE_PACKET_HEADER is 0 to work.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: Ie13f6c4dbab5038eb7a7fea6d58ce4451bc551d1
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1762
CI-Build: Philippe Proulx <eeppeliteloop@gmail.com>
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/plugins/ctf/common/metadata/ctf-meta-resolve.c b/src/plugins/ctf/common/metadata/ctf-meta-resolve.c
index e2e5b3f2a786ef834e97054af6ef81e4db84f8ce..630f14ed5e780ab11100c346f6df187260fa9d15 100644 (file)
--- a/src/plugins/ctf/common/metadata/ctf-meta-resolve.c
+++ b/src/plugins/ctf/common/metadata/ctf-meta-resolve.c
@@ -265,14 +265,14 @@ enum ctf_scope get_root_scope_from_absolute_pathstr(const char *pathstr,
                struct resolve_context *ctx)
 {
        enum ctf_scope scope;
-       enum ctf_scope ret = -1;
+       enum ctf_scope ret = CTF_SCOPE_PACKET_UNKNOWN;
        const size_t prefixes_count = sizeof(absolute_path_prefixes) /
                sizeof(*absolute_path_prefixes);
 
        for (scope = CTF_SCOPE_PACKET_HEADER; scope < CTF_SCOPE_PACKET_HEADER +
                        prefixes_count; scope++) {
                /*
-                * Chech if path string starts with a known absolute
+                * Check if path string starts with a known absolute
                 * path prefix.
                 *
                 * Refer to CTF 7.3.2 STATIC AND DYNAMIC SCOPES.
@@ -661,7 +661,7 @@ int pathstr_to_field_path(const char *pathstr,
        /* Absolute or relative path? */
        root_scope = get_root_scope_from_absolute_pathstr(pathstr, ctx);
 
-       if (root_scope == -1) {
+       if (root_scope == CTF_SCOPE_PACKET_UNKNOWN) {
                /* Relative path: start with current root scope */
                field_path->root = ctx->root_scope;
                BT_COMP_LOGD("Detected relative path: starting with current root scope: "

diff --git a/src/plugins/ctf/common/metadata/ctf-meta.h b/src/plugins/ctf/common/metadata/ctf-meta.h
index c5874ad1f5b4b5676065130f8f85114bc02b81d1..8db2dee4ea6588a94d2f47834d06930793125ed4 100644 (file)
--- a/src/plugins/ctf/common/metadata/ctf-meta.h
+++ b/src/plugins/ctf/common/metadata/ctf-meta.h
@@ -61,7 +61,8 @@ enum ctf_encoding {
 };
 
 enum ctf_scope {
-       CTF_SCOPE_PACKET_HEADER,
+       CTF_SCOPE_PACKET_UNKNOWN = -1,
+       CTF_SCOPE_PACKET_HEADER = 0,
        CTF_SCOPE_PACKET_CONTEXT,
        CTF_SCOPE_EVENT_HEADER,
        CTF_SCOPE_EVENT_COMMON_CONTEXT,