binutils/binutils-ppc-gas-machine-directive.patch

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From cebc89b9328eab994f6b0314c263f94e7949a553 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Mon, 21 Feb 2022 10:58:57 +1030
Subject: [PATCH] binutils 2.38 vs. ppc32 linux kernel
Commit b25f942e18d6 made .machine more strict. Weaken it again.
* config/tc-ppc.c (ppc_machine): Treat an early .machine specially,
keeping sticky options to work around gcc bugs.
---
gas/config/tc-ppc.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/gas/config/tc-ppc.c b/gas/config/tc-ppc.c
index 054f9c72161..89bc7d3f9b9 100644
--- a/gas/config/tc-ppc.c
+++ b/gas/config/tc-ppc.c
@@ -5965,7 +5965,30 @@ ppc_machine (int ignore ATTRIBUTE_UNUSED)
options do not count as a new machine, instead they add
to currently selected opcodes. */
ppc_cpu_t machine_sticky = 0;
- new_cpu = ppc_parse_cpu (ppc_cpu, &machine_sticky, cpu_string);
+ /* Unfortunately, some versions of gcc emit a .machine
+ directive very near the start of the compiler's assembly
+ output file. This is bad because it overrides user -Wa
+ cpu selection. Worse, there are versions of gcc that
+ emit the *wrong* cpu, not even respecting the -mcpu given
+ to gcc. See gcc pr101393. And to compound the problem,
+ as of 20220222 gcc doesn't pass the correct cpu option to
+ gas on the command line. See gcc pr59828. Hack around
+ this by keeping sticky options for an early .machine. */
+ asection *sec;
+ for (sec = stdoutput->sections; sec != NULL; sec = sec->next)
+ {
+ segment_info_type *info = seg_info (sec);
+ /* Are the frags for this section perturbed from their
+ initial state? Even .align will count here. */
+ if (info != NULL
+ && (info->frchainP->frch_root != info->frchainP->frch_last
+ || info->frchainP->frch_root->fr_type != rs_fill
+ || info->frchainP->frch_root->fr_fix != 0))
+ break;
+ }
+ new_cpu = ppc_parse_cpu (ppc_cpu,
+ sec == NULL ? &sticky : &machine_sticky,
+ cpu_string);
if (new_cpu != 0)
ppc_cpu = new_cpu;
else
--
2.37.1