>From 283110f7979af5404dffa87265ab4c6ee33f8104 Mon Sep 17 00:00:00 2001 From: Olivier Hainque Date: Wed, 12 Dec 2018 07:15:13 -0800 Subject: [PATCH 4/4] Allow target (OS) configuration to state R18 as reserved on aarch64 * config/aarch64/aarch64.h (FIXED_R18): New internal configuration macro, defaulted to 0. (FIXED_REGISTERS): Use it. --- gcc/config/aarch64/aarch64.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index a8063c2..89eb0c5 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -287,11 +287,17 @@ extern unsigned aarch64_architecture_version; /* Standard register usage. */ +/* Whether R18, the "platform register", is used as such by the target + environment, and may thus not be used as a scratch register. This may + be redefined to 1 by os specific configurations. */ +#define FIXED_R18 0 + /* 31 64-bit general purpose registers R0-R30: R30 LR (link register) R29 FP (frame pointer) R19-R28 Callee-saved registers - R18 The platform register; use as temporary register. + R18 The platform register; available as temporary register + unless FIXED_R18 is set. R17 IP1 The second intra-procedure-call temporary register (can be used by call veneers and PLT code); otherwise use as a temporary register @@ -327,7 +333,7 @@ extern unsigned aarch64_architecture_version; { \ 0, 0, 0, 0, 0, 0, 0, 0, /* R0 - R7 */ \ 0, 0, 0, 0, 0, 0, 0, 0, /* R8 - R15 */ \ - 0, 0, 0, 0, 0, 0, 0, 0, /* R16 - R23 */ \ + 0, 0, FIXED_R18, 0, 0, 0, 0, 0, /* R16 - R23 */ \ 0, 0, 0, 0, 0, 1, 0, 1, /* R24 - R30, SP */ \ 0, 0, 0, 0, 0, 0, 0, 0, /* V0 - V7 */ \ 0, 0, 0, 0, 0, 0, 0, 0, /* V8 - V15 */ \ -- 1.9.1