regcomp.c: Don't read uninitialized data

I keep forgetting that the OP of a regnode is not defined in Pass 1 of
the regex compiler.  This is likely the cause of inconsistent results in
lib/locale.t, as valgrind shows there to be a read of uninitialized
data before this patch, and the result is randomly tainting when there
shouldn't be, consistent with the test failures.

diff --git a/embed.fnc b/embed.fnc
index d0943e8..f747aae 100644 (file)
--- a/embed.fnc
+++ b/embed.fnc
@@ -2079,7 +2079,7 @@ EsRn      |char * |regpatws       |NN RExC_state_t *pRExC_state \
                                |NN char *p|const bool recognize_comment
 Ei     |void   |alloc_maybe_populate_EXACT|NN RExC_state_t *pRExC_state \
                                |NN regnode *node|NN I32 *flagp|STRLEN len \
-                               |UV code_point|const bool downgradable
+                               |UV code_point|bool downgradable
 Ei     |U8   |compute_EXACTish|NN RExC_state_t *pRExC_state
 Es     |char * |nextchar       |NN RExC_state_t *pRExC_state
 Es     |bool   |reg_skipcomment|NN RExC_state_t *pRExC_state

diff --git a/proto.h b/proto.h
index 4832535..e032ad6 100644 (file)
--- a/proto.h
+++ b/proto.h
@@ -6607,7 +6607,7 @@ STATIC U32        S_add_data(RExC_state_t* const pRExC_state, const char* const s, cons
 #define PERL_ARGS_ASSERT_ADD_DATA      \
        assert(pRExC_state); assert(s)
 
-PERL_STATIC_INLINE void        S_alloc_maybe_populate_EXACT(pTHX_ RExC_state_t *pRExC_state, regnode *node, I32 *flagp, STRLEN len, UV code_point, const bool downgradable)
+PERL_STATIC_INLINE void        S_alloc_maybe_populate_EXACT(pTHX_ RExC_state_t *pRExC_state, regnode *node, I32 *flagp, STRLEN len, UV code_point, bool downgradable)
                        __attribute__nonnull__(pTHX_1)
                        __attribute__nonnull__(pTHX_2)
                        __attribute__nonnull__(pTHX_3);

diff --git a/regcomp.c b/regcomp.c
index b3a4845..efd0a47 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -10882,7 +10882,7 @@ S_compute_EXACTish(pTHX_ RExC_state_t *pRExC_state)
 PERL_STATIC_INLINE void
 S_alloc_maybe_populate_EXACT(pTHX_ RExC_state_t *pRExC_state,
                          regnode *node, I32* flagp, STRLEN len, UV code_point,
-                         const bool downgradable)
+                         bool downgradable)
 {
     /* This knows the details about sizing an EXACTish node, setting flags for
      * it (by setting <*flagp>, and potentially populating it with a single
@@ -10916,6 +10916,12 @@ S_alloc_maybe_populate_EXACT(pTHX_ RExC_state_t *pRExC_state,
 
     PERL_ARGS_ASSERT_ALLOC_MAYBE_POPULATE_EXACT;
 
+    /* Don't bother to check for downgrading in PASS1, as it doesn't make any
+     * sizing difference, and is extra work that is thrown away */
+    if (downgradable && ! PASS2) {
+        downgradable = FALSE;
+    }
+
     if (! len_passed_in) {
         if (UTF) {
             if (UNI_IS_INVARIANT(code_point)) {
@@ -11020,7 +11026,8 @@ S_alloc_maybe_populate_EXACT(pTHX_ RExC_state_t *pRExC_state,
         *flagp |= SIMPLE;
     }
 
-    if (OP(node) == EXACTFL) {
+    /* The OP may not be well defined in PASS1 */
+    if (PASS2 && OP(node) == EXACTFL) {
         RExC_contains_locale = 1;
     }
 }