[Patch, darwin] do not generate branch islands when the linker can do it.

[IainS <developer at sandoe-acoustics dot co dot uk>]

Hi,
This hugely  tidies up *-*-darwin{9,10} asm by omitting the branch  
islands where they are not needed.

I've had it in my local tree for a month or so .. and it's been  
bootstrapped on x86_64-unknown-linux-gnu as well as a number of cross- 
targets.

I don't have a second rs6000 target but, by inspection, the changes  
are within code already wrapped by #ifdef MACH_O.

We must not put the "darwin_emit_branch_islands" declaration into  
darwin.h or I think it will mess up the (small amount of) binutils  
stuff that currently works for darwin.  Hence the reason it appears in  
both i386/darwin.h and rs6000/darwin.h

OK for trunk?
Iain


	* config/i386/darwin.h: Define darwin_emit_branch_islands.
	(FUNCTION_PROFILER): Do not emit branch islands unless
	darwin_emit_branch_islands is set.
	* config/i386/i386.c (output_pic_addr_const): Do not emit
	branch islands unless darwin_emit_branch_islands is set.
	(x86_output_mi_thunk): Adjust symbol creation.
	* config/rs6000/darwin.h: Define darwin_emit_branch_islands.
	Remove out of date comment.
	* config/rs6000/rs6000.c (print_operand): Adjust symbol.
	DARWIN_LINKER_GENERATES_ISLANDS: Remove.
	DARWIN_GENERATE_ISLANDS: Ditto.
	(output_call):  Do not emit branch islands unless
	darwin_emit_branch_islands is set.
	* config/darwin.c: Declare darwin_emit_branch_islands.
	(machopic_indirect_data_reference): Do not emit unless
	darwin_emit_branch_islands is set.
	(darwin_override_options): Set darwin_emit_branch_islands
	where it is needed.
	* config/darwin9.h
	DARWIN_LINKER_GENERATES_ISLANDS: Remove.

Attachment: 162209-darwin-branch-islands.txt
Description: Text document