The attached change implements a new -mcaller-copies option on hppa. The default 32-bit runtime
specifies that the callee copies arguments passed by hidden reference. This is optimal but it causes
problems with openmp. See PR middle-end/68733:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68733
It's not clear openmp can be fixed to work with callee copies targets.
This option provides a work around. The general consensus is that caller copies is better tested
and it seems probable that we will switch to caller copies on Debian when we switch to gcc-7.
Tested on hppa-unknown-linux-gnu, hppa2.0w-hp-hpux11.11 and hppa64-hp-hpux11.11 with no observed
regression. When enabled, it fixes the failures noted in PR 68733.
Committed to trunk.
Dave
--
John David Anglin dave.anglin@xxxxxxxx
2012-12-11 John David Anglin <danglin@xxxxxxxxxxx>
* config/pa/pa.c (pa_callee_copies): New function.
* config/pa/pa.opt (mcaller-copies): New option.
* doc/invoke.texi (mcaller-copies): Document option.
Index: config/pa/pa.c
===================================================================
--- config/pa/pa.c (revision 243232)
+++ config/pa/pa.c (working copy)
@@ -195,6 +195,8 @@
static bool pa_legitimate_constant_p (machine_mode, rtx);
static unsigned int pa_section_type_flags (tree, const char *, int);
static bool pa_legitimate_address_p (machine_mode, rtx, bool);
+static bool pa_callee_copies (cumulative_args_t, machine_mode,
+ const_tree, bool);
/* The following extra sections are only used for SOM. */
static GTY(()) section *som_readonly_data_section;
@@ -343,7 +345,7 @@
#undef TARGET_PASS_BY_REFERENCE
#define TARGET_PASS_BY_REFERENCE pa_pass_by_reference
#undef TARGET_CALLEE_COPIES
-#define TARGET_CALLEE_COPIES hook_bool_CUMULATIVE_ARGS_mode_tree_bool_true
+#define TARGET_CALLEE_COPIES pa_callee_copies
#undef TARGET_ARG_PARTIAL_BYTES
#define TARGET_ARG_PARTIAL_BYTES pa_arg_partial_bytes
#undef TARGET_FUNCTION_ARG
@@ -10720,4 +10722,19 @@
return NULL_RTX;
}
+/* Implement TARGET_CALLEE_COPIES. The callee is responsible for copying
+ arguments passed by hidden reference in the 32-bit HP runtime. Users
+ can override this behavior for better compatibility with openmp at the
+ risk of library incompatibilities. Arguments are always passed by value
+ in the 64-bit HP runtime. */
+
+static bool
+pa_callee_copies (cumulative_args_t cum ATTRIBUTE_UNUSED,
+ machine_mode mode ATTRIBUTE_UNUSED,
+ const_tree type ATTRIBUTE_UNUSED,
+ bool named ATTRIBUTE_UNUSED)
+{
+ return !TARGET_CALLER_COPIES;
+}
+
#include "gt-pa.h"
Index: config/pa/pa.opt
===================================================================
--- config/pa/pa.opt (revision 243232)
+++ config/pa/pa.opt (working copy)
@@ -41,6 +41,10 @@
Target Ignore
Does nothing. Preserved for backward compatibility.
+mcaller-copies
+Target Report Mask(CALLER_COPIES)
+Caller copies function arguments passed by hidden reference.
+
mdisable-fpregs
Target Report Mask(DISABLE_FPREGS)
Disable FP regs.
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi (revision 243232)
+++ doc/invoke.texi (working copy)
@@ -761,7 +761,7 @@
@emph{HPPA Options}
@gccoptlist{-march=@var{architecture-type} @gol
--mdisable-fpregs -mdisable-indexing @gol
+-mcaller-copies -mdisable-fpregs -mdisable-indexing @gol
-mfast-indirect-calls -mgas -mgnu-ld -mhp-ld @gol
-mfixed-range=@var{register-range} @gol
-mjump-in-delay -mlinker-opt -mlong-calls @gol
@@ -17363,6 +17363,14 @@
@opindex mpa-risc-2-0
Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively.
+@item -mcaller-copies
+@opindex mcaller-copies
+The caller copies function arguments passed by hidden reference. This
+option should be used with care as it is not compatible with the default
+32-bit runtime. However, only aggregates larger than eight bytes are
+passed by hidden reference and the option provides better compatibility
+with openmp.
+
@item -mjump-in-delay
@opindex mjump-in-delay
This option is ignored and provided for compatibility purposes only.
