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Alan Modra [Thu, 29 Nov 2018 04:47:51 +0000 (15:17 +1030)]

[RS6000] Use standard call patterns for __tls_get_addr calls

The current code handling __tls_get_addr calls for powerpc*-linux
generates a call then overwrites the call insn with a special
tls_{gd,ld}_{aix,sysv} pattern.  It's done that way to support
!TARGET_TLS_MARKERS, where the arg setup insns need to be emitted
immediately before the branch and link.  When TARGET_TLS_MARKERS, the
arg setup insns are split from the actual call, but we then have a
non-standard call pattern that needs to be carried through to output.

This patch changes that scheme, to instead use the standard call
patterns for __tls_get_addr calls, except for the now rare
!TARGET_TLS_MARKERS case.  Doing it this way should be better for
maintenance as the !TARGET_TLS_MARKERS code can eventually disappear.
It also makes it possible to support longcalls (and in following
patches, inline plt calls) for __tls_get_addr without introducing yet
more special call patterns.

__tls_get_addr calls do however need to be different to standard
calls, because when TARGET_TLS_MARKERS the calls are decorated with an
argument specifier, eg. "bl __tls_get_addr(thread_var@tlsgd)" that
causes a reloc to be emitted by the assembler tying the call to its
arg setup insns.  I chose to smuggle the arg in the currently unused
stack size rtl.

I've also introduced rs6000_call_sysv to generate rtl for sysv calls,
as rs6000_call_aix does for aix and elfv2 calls.  This allows
rs6000_longcall_ref to be local to rs6000.c since the calls in the
expanders never did anything for darwin.

* config/rs6000/predicates.md (unspec_tls): New.
* config/rs6000/rs6000-protos.h (rs6000_call_template),
(rs6000_sibcall_template): Update prototype.
(rs6000_longcall_ref): Delete.
(rs6000_call_sysv): Declare.
* config/rs6000/rs6000.c (edit_tls_call_insn): New function.
(global_tlsarg): New variable.
(rs6000_legitimize_tls_address): Rewrite __tls_get_addr call
handling.
(print_operand): Extract UNSPEC_TLSGD address operand.
(rs6000_call_template, rs6000_sibcall_template): Remove arg
parameter, extract from second call operand instead.
(rs6000_longcall_ref): Make static, localize vars.
(rs6000_call_aix): Rename parameter to reflect new usage.  Take
tlsarg from global_tlsarg.  Don't create unused rtl or nop insns.
(rs6000_sibcall_aix): Rename parameter to reflect new usage.  Take
tlsarg from global_tlsarg.
(rs6000_call_sysv): New function.
* config/rs6000/rs6000.md: Adjust rs6000_call_template and
rs6000_sibcall_template throughout.
(tls_gd_aix, tls_gd_sysv, tls_gd_call_aix, tls_gd_call_sysv): Delete.
(tls_ld_aix, tls_ld_sysv, tls_ld_call_aix, tls_ld_call_sysv): Delete.
(tls_gdld_nomark): New insn.
(tls_gd): Swap operand order.  Simplify mode selection.
(tls_gd_high, tls_gd_low): Swap operand order.
(tls_ld): Remove const_int 0 vector element from UNSPEC_TLSLD.
Simplify mode selection.
(tls_ld_high, tls_ld_low): Similarly adjust UNSPEC_TLSLD.
(call, call_value): Don't assert for second call operand.
Use rs6000_call_sysv.

From-SVN: r266604