[gcc r10-9189] Darwin: Adjust the PCH area to allow for 16384byte page size.

[Iain D Sandoe]

https://gcc.gnu.org/g:d0bae0b218d54aedb439381e5e4480e862f42f8b

commit r10-9189-gd0bae0b218d54aedb439381e5e4480e862f42f8b
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat Aug 8 12:15:09 2020 +0100

    Darwin: Adjust the PCH area to allow for 16384byte page size.
    
    Newer versions of Darwin report pagesize 20 which means that we
    need to adjust the aligment of the PCH area.
    
    gcc/ChangeLog:
    
            * config/host-darwin.c: Align pch_address_space to 16384.
    
    (cherry picked from commit 590febb5f6624f78b36402a7c9a9c318978f1efa)

Diff:
---
 gcc/config/host-darwin.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/gcc/config/host-darwin.c b/gcc/config/host-darwin.c
index 0face6c450f..c862935dcf3 100644
--- a/gcc/config/host-darwin.c
+++ b/gcc/config/host-darwin.c
@@ -24,7 +24,10 @@
 #include "config/host-darwin.h"
 
 /* Yes, this is really supposed to work.  */
-static char pch_address_space[1024*1024*1024] __attribute__((aligned (4096)));
+/* This allows for a pagesize of 16384, which we have on Darwin20, but should
+   continue to work OK for pagesize 4096 which we have on earlier versions.
+   The size is 1 (binary) Gb.  */
+static char pch_address_space[65536*16384] __attribute__((aligned (16384)));
 
 /* Return the address of the PCH address space, if the PCH will fit in it.  */