From 62fbdb5da05f6f11fc6bdeaefa178fe08eaaec86 Mon Sep 17 00:00:00 2001
From: Zoltan Herczeg <hzmester@freemail.hu>
Date: Mon, 2 Sep 2024 09:28:42 +0000
Subject: [PATCH] Support *THEN for non-atomic assertions

---
 src/pcre2_jit_compile.c | 67 +++++++++++++++++++++++++----------------
 testdata/testinput2     | 15 +++++++++
 testdata/testoutput2    | 34 +++++++++++++++++++++
 3 files changed, 90 insertions(+), 26 deletions(-)

diff --git a/src/pcre2_jit_compile.c b/src/pcre2_jit_compile.c
index b8913474d..f04e165b9 100644
--- a/src/pcre2_jit_compile.c
+++ b/src/pcre2_jit_compile.c
@@ -3160,50 +3160,66 @@ static SLJIT_INLINE PCRE2_SPTR set_then_offsets(compiler_common *common, PCRE2_S
 PCRE2_SPTR end = bracketend(cc);
 BOOL has_alternatives = cc[GET(cc, 1)] == OP_ALT;
 
-/* Assert captures then. */
-if (*cc >= OP_ASSERT && *cc <= OP_ASSERTBACK_NA)
+/* Assert captures *THEN verb even if it has no alternatives. */
+if (*cc >= OP_ASSERT && *cc <= OP_ASSERTBACK_NOT)
   current_offset = NULL;
-/* Conditional block does not. */
-if (*cc == OP_COND || *cc == OP_SCOND)
+else if (*cc >= OP_ASSERT_NA && *cc <= OP_ASSERT_SCS)
+  has_alternatives = TRUE;
+/* Conditional block does never capture. */
+else if (*cc == OP_COND || *cc == OP_SCOND)
   has_alternatives = FALSE;
 
 cc = next_opcode(common, cc);
 
 if (has_alternatives)
   {
-  if (*cc == OP_REVERSE)
-    cc += 1 + IMM2_SIZE;
-  else if (*cc == OP_VREVERSE)
-    cc += 1 + 2 * IMM2_SIZE;
+  switch (*cc)
+    {
+    case OP_REVERSE:
+    case OP_CREF:
+      cc += 1 + IMM2_SIZE;
+      break;
+    case OP_VREVERSE:
+    case OP_DNCREF:
+      cc += 1 + 2 * IMM2_SIZE;
+      break;
+    }
 
   current_offset = common->then_offsets + (cc - common->start);
   }
 
 while (cc < end)
   {
-  if ((*cc >= OP_ASSERT && *cc <= OP_ASSERTBACK_NA) || (*cc >= OP_ONCE && *cc <= OP_SCOND))
-    cc = set_then_offsets(common, cc, current_offset);
-  else
+  if (*cc >= OP_ASSERT && *cc <= OP_SCOND)
     {
-    if (*cc == OP_ALT && has_alternatives)
-      {
-      cc += 1 + LINK_SIZE;
+    cc = set_then_offsets(common, cc, current_offset);
+    continue;
+    }
 
-      if (*cc == OP_REVERSE)
-        cc += 1 + IMM2_SIZE;
-      else if (*cc == OP_VREVERSE)
-        cc += 1 + 2 * IMM2_SIZE;
+  if (*cc == OP_ALT && has_alternatives)
+    {
+    cc += 1 + LINK_SIZE;
 
-      current_offset = common->then_offsets + (cc - common->start);
-      continue;
-      }
+    if (*cc == OP_REVERSE)
+      cc += 1 + IMM2_SIZE;
+    else if (*cc == OP_VREVERSE)
+      cc += 1 + 2 * IMM2_SIZE;
 
-    if (*cc >= OP_THEN && *cc <= OP_THEN_ARG && current_offset != NULL)
-      *current_offset = 1;
-    cc = next_opcode(common, cc);
+    current_offset = common->then_offsets + (cc - common->start);
+    continue;
     }
+
+  if (*cc >= OP_THEN && *cc <= OP_THEN_ARG && current_offset != NULL)
+    *current_offset = 1;
+  cc = next_opcode(common, cc);
   }
 
+cc = end - 1 - LINK_SIZE;
+
+/* Ignore repeats. */
+if (*cc == OP_KET && PRIVATE_DATA(cc) != 0)
+  end += PRIVATE_DATA(cc + 1);
+
 return end;
 }
 
@@ -6789,8 +6805,7 @@ jump = JUMP(SLJIT_NOT_ZERO /* SIG_LESS */);
 OP_SRC(SLJIT_FAST_RETURN, RETURN_ADDR, 0);
 
 JUMPHERE(jump);
-OP2(SLJIT_SUB, TMP2, 0, SLJIT_IMM, 0, TMP2, 0);
-OP2(SLJIT_ADD, TMP2, 0, TMP2, 0, TMP1, 0);
+OP2(SLJIT_SUB, TMP2, 0, TMP1, 0, TMP2, 0);
 if (HAS_VIRTUAL_REGISTERS)
   {
   OP1(SLJIT_MOV, SLJIT_MEM1(TMP2), 0, SLJIT_MEM1(STACK_TOP), -(2 * SSIZE_OF(sw)));
diff --git a/testdata/testinput2 b/testdata/testinput2
index 702d0c256..f83af896e 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -6330,6 +6330,21 @@ a)"xI
 /^([a-z]++)#(*scs:(1)a|ab|abc|abcd|abcde|abcdef|(abcdefg))\2/
     abcdefg#abcdefg
 
+/^([a-z]++)(*scs:(1)(a+)(*THEN)b|(a+)(*THEN)c|(aa))/
+    aaaax
+
+/^([a-z]++)(*scs:(1)((a+)(*THEN)b)|(a+)(*THEN)c|(aa))/
+    aaaax
+
+/^([a-z]++)(*scs:(1)((a+)(*THEN)b))?/
+    aaaax
+
+/^([a-z]++)(*scs:(1)(abc|(a+)(*THEN)b))?/
+    aaaax
+
+/^([a-z]++)(*scs:(1)(a+)(*THEN)b){20,30}#|(.){20,30}/
+    aaaaaaaaaaaaaaaaaaaaaaaaab!
+
 # --------------
 
 # End of testinput2
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index db9c7a7c1..c9849d3e5 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -18787,6 +18787,40 @@ No match
  1: abcdefg
  2: abcdefg
 
+/^([a-z]++)(*scs:(1)(a+)(*THEN)b|(a+)(*THEN)c|(aa))/
+    aaaax
+ 0: aaaax
+ 1: aaaax
+ 2: <unset>
+ 3: <unset>
+ 4: aa
+
+/^([a-z]++)(*scs:(1)((a+)(*THEN)b)|(a+)(*THEN)c|(aa))/
+    aaaax
+ 0: aaaax
+ 1: aaaax
+ 2: <unset>
+ 3: <unset>
+ 4: <unset>
+ 5: aa
+
+/^([a-z]++)(*scs:(1)((a+)(*THEN)b))?/
+    aaaax
+ 0: aaaax
+ 1: aaaax
+
+/^([a-z]++)(*scs:(1)(abc|(a+)(*THEN)b))?/
+    aaaax
+ 0: aaaax
+ 1: aaaax
+
+/^([a-z]++)(*scs:(1)(a+)(*THEN)b){20,30}#|(.){20,30}/
+    aaaaaaaaaaaaaaaaaaaaaaaaab!
+ 0: aaaaaaaaaaaaaaaaaaaaaaaaab!
+ 1: <unset>
+ 2: <unset>
+ 3: !
+
 # --------------
 
 # End of testinput2