[llvm] [Support] Fix buffer overflow in regcomp (PR #76681)

[via llvm-commits]

github-actions[bot] wrote:

<!--LLVM CODE FORMAT COMMENT: {clang-format}-->


:warning: C/C++ code formatter, clang-format found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

``````````bash
git-clang-format --diff 463dad107f4cb60ae1d49138143d6797599fb1fb 22fcd1ef7e9a79a861313bc0f2d4c84767e2a0e8 -- llvm/lib/Support/regcomp.c
``````````

</details>

<details>
<summary>
View the diff from clang-format here.
</summary>

``````````diff
diff --git a/llvm/lib/Support/regcomp.c b/llvm/lib/Support/regcomp.c
index 1f68008d6a..08ef1adcc5 100644
--- a/llvm/lib/Support/regcomp.c
+++ b/llvm/lib/Support/regcomp.c
@@ -1601,9 +1601,9 @@ findmust(struct parse *p, struct re_guts *g)
 	sop s;
 	char *cp;
 	sopno i;
-	unsigned int skipsize;
+        unsigned int skipsize;
 
-	/* avoid making error situations worse */
+        /* avoid making error situations worse */
 	if (p->error != 0)
 		return;
 
@@ -1626,17 +1626,17 @@ findmust(struct parse *p, struct re_guts *g)
 		case OCH_:
 			scan--;
 			do {
-				/* Ensure end is not skipped */
-				skipsize = OPND(s);
-				while (skipsize > 0) {
-					if (OP(*scan) == OEND) {
-						g->iflags |= REGEX_BAD;
-						return;
-					}
-					scan++;
-					skipsize--;
-				}
-				s = *scan;
+                          /* Ensure end is not skipped */
+                          skipsize = OPND(s);
+                          while (skipsize > 0) {
+                            if (OP(*scan) == OEND) {
+                              g->iflags |= REGEX_BAD;
+                              return;
+                            }
+                            scan++;
+                            skipsize--;
+                          }
+                                s = *scan;
 				/* assert() interferes w debug printouts */
 				if (OP(s) != O_QUEST && OP(s) != O_CH &&
 							OP(s) != OOR2) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/76681