src: ignore maybe-uninitialized warning string_search

danbev · danbev · commit b520c74dfd3c · 2020-01-27T14:14:50.000+01:00
Currently, the following compilation warning is generated with GCC
version 8.2.1:

In file included from ../src/node_buffer.cc:29:
../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector&lt;const Char&gt;,
    node::stringsearch::Vector&lt;const Char&gt;,
    size_t) [with Char = short unsigned int]’:
../src/string_search.h:113:30: warning:
‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this-&gt;*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

../src/string_search.h:
In function ‘size_t node::stringsearch::SearchString(
    node::stringsearch::Vector&lt;const Char&gt;,
    node::stringsearch::Vector&lt;const Char&gt;,
    size_t) [with Char = unsigned char]’:
../src/string_search.h:113:30:
warning: ‘search’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
     return (this-&gt;*strategy_)(subject, index);
            ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

The issue here seems to be with the `strategy_` field which is a pointer
to a member function, and it is set in the constructor of StringSearch.
It is always set and I've not been able to work around this warning
so this commit suggests adding a pragma for GCC to ignore the warning.
diff --git a/src/string_search.h b/src/string_search.h
@@ -110,7 +110,14 @@ class StringSearch : private StringSearchBase {
   }
 
   size_t Search(Vector subject, size_t index) {
+#if (__GNUC__ >= 8) && !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
     return (this->*strategy_)(subject, index);
+#if (__GNUC__ >= 8) && !defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
   }
 
   static inline int AlphabetSize() {

Original file line number	Diff line number	Diff line change
`@@ -110,7 +110,14 @@ class StringSearch : private StringSearchBase {`
`110`	`110`	`}`
`111`	`111`
`112`	`112`	`size_t Search(Vector subject, size_t index) {`
	`113`	`+#if (__GNUC__ >= 8) && !defined(__clang__)`
	`114`	`+#pragma GCC diagnostic push`
	`115`	`+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"`
	`116`	`+#endif`
`113`	`117`	`return (this->*strategy_)(subject, index);`
	`118`	`+#if (__GNUC__ >= 8) && !defined(__clang__)`
	`119`	`+#pragma GCC diagnostic pop`
	`120`	`+#endif`
`114`	`121`	`}`
`115`	`122`
`116`	`123`	`static inline int AlphabetSize() {`