ggc: Reduce GGC_QUIRE_SIZE on Solaris/SPARC [PR115031]

g++.dg/modules/pr99023_b.X currently FAILs on 32-bit Solaris/SPARC:

FAIL: g++.dg/modules/pr99023_b.X -std=c++2a  1 blank line(s) in output
FAIL: g++.dg/modules/pr99023_b.X -std=c++2a (test for excess errors)

Excess errors:
cc1plus: out of memory allocating 1048344 bytes after a total of 7913472 bytes

It turns out that this exhaustion of the 32-bit address space happens
due to a combination of three issues:

* the SPARC pagesize of 8 kB,

* ggc-page.cc's chunk size of 512 * pagesize, i.e. 4 MB, and

* mmap adding two 8 kB unmapped red-zone pages to each mapping

which result in the 4 MB mappings to actually consume 4.5 MB of address
space.

To avoid this, this patch reduces the chunk size so it remains at 4 MB
even when combined with the red-zone pages, as recommended by mmap(2).

Tested on sparc-sun-solaris2.11 and sparcv9-sun-solaris2.11.

2024-05-29  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc:
	PR c++/115031
	* config/sparc/sol2.h (GGC_QUIRE_SIZE): Define as 510.

diff --git a/gcc/config/sparc/sol2.h b/gcc/config/sparc/sol2.h
index 552f58b2cc87c99a42342688e42383dcbff005cc..530e681aaee127ba386e87749b0220698d061a7f 100644 (file)
--- a/gcc/config/sparc/sol2.h
+++ b/gcc/config/sparc/sol2.h
@@ -38,6 +38,9 @@ along with GCC; see the file COPYING3.  If not see
 #undef SPARC_DEFAULT_CMODEL
 #define SPARC_DEFAULT_CMODEL CM_MEDMID
 
+/* Redue ggc-page.cc's chunk size to account for mmap red-zone pages.  */
+#define GGC_QUIRE_SIZE 510
+
 /* Select a format to encode pointers in exception handling data.  CODE
    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
    true if the symbol may be affected by dynamic relocations.