read-cache: fix an -Wmaybe-uninitialized warning

diff --git a/grep.c b/grep.c
index a69c05edc2e4fc6787076531b43a49c7ccdc1113..3d7cd0e96f1ee160a66dd500c58d4026bf24e34c 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -477,6 +477,8 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
        int options = PCRE2_MULTILINE;
        const uint8_t *character_tables = NULL;
        int jitret;
+       int patinforet;
+       size_t jitsizearg;
 
        assert(opt->pcre2);
 
@@ -511,6 +513,30 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
                jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE);
                if (jitret)
                        die("Couldn't JIT the PCRE2 pattern '%s', got '%d'\n", p->pattern, jitret);
+
+               /*
+                * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just
+                * tells us whether the library itself supports JIT,
+                * but to see whether we're going to be actually using
+                * JIT we need to extract PCRE2_INFO_JITSIZE from the
+                * pattern *after* we do pcre2_jit_compile() above.
+                *
+                * This is because if the pattern contains the
+                * (*NO_JIT) verb (see pcre2syntax(3))
+                * pcre2_jit_compile() will exit early with 0. If we
+                * then proceed to call pcre2_jit_match() further down
+                * the line instead of pcre2_match() we'll either
+                * segfault (pre PCRE 10.31) or run into a fatal error
+                * (post PCRE2 10.31)
+                */
+               patinforet = pcre2_pattern_info(p->pcre2_pattern, PCRE2_INFO_JITSIZE, &jitsizearg);
+               if (patinforet)
+                       BUG("pcre2_pattern_info() failed: %d", patinforet);
+               if (jitsizearg == 0) {
+                       p->pcre2_jit_on = 0;
+                       return;
+               }
+
                p->pcre2_jit_stack = pcre2_jit_stack_create(1, 1024 * 1024, NULL);
                if (!p->pcre2_jit_stack)
                        die("Couldn't allocate PCRE2 JIT stack");