From: Guy Harris <gharris@sonic.net>
Date: Sat, 5 Aug 2023 20:28:53 +0000 (-0700)
Subject: Make nd_trunc_longjmp() not static inline.
X-Git-Tag: tcpdump-4.99.5~179
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/59b65340e619f3d898ff2ca5b3a8b5d5df894d73

Make nd_trunc_longjmp() not static inline.

It should rarely be called (if it's called, either the packet was cut
short by snapshot-based slicing or it's malformed, or the dissector has
a bug), so inlining it doesn't help much, and, as it calls longjmp(),
which often expands to a call to __builtin_longjmp(), GCC won't inline
it anyway (see "An Inline Function is As Fast As a Macro" in the GCC
documentation), and Apple clang version 14.0.3 (clang-1403.0.22.14.1),
at least, doesn't inline it, either, so you get a bunch of inlined
definitions of it throughout the generated code.

Just make it a regular routine.

(cherry picked from commit 5faefb7542821b54193414fe03d7650c25d05380)
---

diff --git a/netdissect.c b/netdissect.c
index 000d1ffc..93e633a6 100644
--- a/netdissect.c
+++ b/netdissect.c
@@ -299,3 +299,17 @@ nd_pop_all_packet_info(netdissect_options *ndo)
 	while (ndo->ndo_packet_info_stack != NULL)
 		nd_pop_packet_info(ndo);
 }
+
+NORETURN void
+nd_trunc_longjmp(netdissect_options *ndo)
+{
+	longjmp(ndo->ndo_early_end, ND_TRUNCATED);
+#ifdef _AIX
+	/*
+	 * In AIX <setjmp.h> decorates longjmp() with "#pragma leaves", which tells
+	 * XL C that the function is noreturn, but GCC remains unaware of that and
+	 * yields a "'noreturn' function does return" warning.
+	 */
+	ND_UNREACHABLE
+#endif /* _AIX */
+}
diff --git a/netdissect.h b/netdissect.h
index 675af511..0eaf8eb2 100644
--- a/netdissect.h
+++ b/netdissect.h
@@ -269,19 +269,10 @@ extern void nd_change_snaplen(netdissect_options *, const u_char *, const u_int)
 extern void nd_pop_packet_info(netdissect_options *);
 extern void nd_pop_all_packet_info(netdissect_options *);
 
-static inline NORETURN void
-nd_trunc_longjmp(netdissect_options *ndo)
-{
-	longjmp(ndo->ndo_early_end, ND_TRUNCATED);
-#ifdef _AIX
-	/*
-	 * In AIX <setjmp.h> decorates longjmp() with "#pragma leaves", which tells
-	 * XL C that the function is noreturn, but GCC remains unaware of that and
-	 * yields a "'noreturn' function does return" warning.
-	 */
-	ND_UNREACHABLE
-#endif /* _AIX */
-}
+/*
+ * Report a packet truncation with a longjmp().
+ */
+NORETURN void nd_trunc_longjmp(netdissect_options *ndo);
 
 #define PT_VAT		1	/* Visual Audio Tool */
 #define PT_WB		2	/* distributed White Board */