re PR debug/48220 (DW_OP_GNU_entry_value/DW_TAG_GNU_call_site_parameter vs register window)

	PR target/48220
	* doc/md.texi (Standard Names): Document window_save.
	* cfgexpand.c (expand_debug_parm_decl): New function extracted from
	expand_debug_expr and expand_debug_source_expr.  If the target has
	a window_save instruction, adjust the ENTRY_VALUE_EXP.
	(expand_debug_expr) <SSA_NAME>: Call expand_debug_parm_decl if the
	SSA_NAME_VAR is a parameter.
	(expand_debug_source_expr) <PARM_DECL>: Call expand_debug_parm_decl.
	* var-tracking.c (parm_reg_t): New type and associated vector type.
	(windowed_parm_regs): New variable.
	(adjust_insn): If the target has a window_save instruction and this
	is the instruction, make its effect on parameter registers explicit.
	(next_non_note_insn_var_location): New function.
	(emit_notes_in_bb): Use it instead of NEXT_INSN throughout.
	(vt_add_function_parameter): If the target has a window_save insn,
	adjust the incoming RTL and record that in windowed_parm_regs.
	(vt_finalize): Free windowed_parm_regs.

From-SVN: r176318

1 files changed, 8 insertions, 0 deletions

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 23047ca..1f08dae 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -5333,6 +5333,14 @@ Using a prologue pattern is generally preferred over defining
 The @code{prologue} pattern is particularly useful for targets which perform
 instruction scheduling.
 
+@cindex @code{window_save} instruction pattern
+@anchor{window_save instruction pattern}
+@item @samp{window_save}
+This pattern, if defined, emits RTL for a register window save.  It should
+be defined if the target machine has register windows but the window events
+are decoupled from calls to subroutines.  The canonical example is the SPARC
+architecture.
+
 @cindex @code{epilogue} instruction pattern
 @anchor{epilogue instruction pattern}
 @item @samp{epilogue}