From: Taylor R Campbell <campbell@mumble.net>
Date: Fri, 1 Feb 2019 05:29:29 +0000 (+0000)
Subject: Comment out bogus ADRP-ADD pseudo-instruction definition.
X-Git-Tag: mit-scheme-pucked-10.1.20~11^2~66^2~15
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=3bdab315ad39bdd86470a23c12d8a3588c68cc04;p=mit-scheme.git

Comment out bogus ADRP-ADD pseudo-instruction definition.

This will cause the compiler to fail noisily if it tries to assemble
code with sufficiently distant PC-relative addresses, which is better
than silently assembling garbage.

Need to find a proper fix.
---

diff --git a/src/compiler/machines/aarch64/instr1.scm b/src/compiler/machines/aarch64/instr1.scm
index f55a1ad5e..995d86cde 100644
--- a/src/compiler/machines/aarch64/instr1.scm
+++ b/src/compiler/machines/aarch64/instr1.scm
@@ -1305,7 +1305,12 @@ USA.
 ;; page-aligned), or we need to generate extra code to find and add PC
 ;; mod 2^12, which looks like it'll require another temporary register.
 ;; Ugh!
+;;
+;; The way that assemblers usually get around this is either by always
+;; relying on relocations or by always aligning code on page boundaries
+;; so that we know PC mod 2^12 anyway.
 
+#;
 (define-instruction ADRP-ADD
   ((X (? Rd) (@PCO (? offset signed-33)))
    (MACRO 32 (ADRP X ,Rd (@PCO (LSL ,(shift-right offset 12) 12)))) ;(*)