amdgcn: Switch to HSACO v3 binary format

amdgcn: Switch to HSACO v3 binary format

This upgrades the compiler to emit HSA Code Object v3 binaries.  This means
changing the assembler directives, and linker command line options.

The gcn-run and libgomp loaders need corresponding alterations.  The
relocations no longer need to be fixed up manually, and the kernel symbol
names have changed slightly.

This move makes the binaries compatible with the new rocgdb from ROCm 3.5.

2020-06-17  Andrew Stubbs  <ams@codesourcery.com>

	gcc/
	* config/gcn/gcn-hsa.h (TEXT_SECTION_ASM_OP): Use ".text".
	(BSS_SECTION_ASM_OP): Use ".bss".
	(ASM_SPEC): Remove "-mattr=-code-object-v3".
	(LINK_SPEC): Add "--export-dynamic".
	* config/gcn/gcn-opts.h (processor_type): Replace PROCESSOR_VEGA with
	PROCESSOR_VEGA10 and PROCESSOR_VEGA20.
	* config/gcn/gcn-run.c (HSA_RUNTIME_LIB): Use ".so.1" variant.
	(load_image): Remove obsolete relocation handling.
	Add ".kd" suffix to the symbol names.
	* config/gcn/gcn.c (MAX_NORMAL_SGPR_COUNT): Set to 62.
	(gcn_option_override): Update gcn_isa test.
	(gcn_kernel_arg_types): Update all the assembler directives.
	Remove the obsolete options.
	(gcn_conditional_register_usage): Update MAX_NORMAL_SGPR_COUNT usage.
	(gcn_omp_device_kind_arch_isa): Handle PROCESSOR_VEGA10 and
	PROCESSOR_VEGA20.
	(output_file_start): Rework assembler file header.
	(gcn_hsa_declare_function_name): Rework kernel metadata.
	* config/gcn/gcn.h (GCN_KERNEL_ARG_TYPES): Set to 16.
	* config/gcn/gcn.opt (PROCESSOR_VEGA): Remove enum.
	(PROCESSOR_VEGA10): New enum value.
	(PROCESSOR_VEGA20): New enum value.

	libgomp/
	* plugin/plugin-gcn.c (init_environment_variables): Use ".so.1"
	variant for HSA_RUNTIME_LIB name.
	(find_executable_symbol_1): Delete.
	(find_executable_symbol): Delete.
	(init_kernel_properties): Add ".kd" suffix to symbol names.
	(find_load_offset): Delete.
	(create_and_finalize_hsa_program): Remove relocation handling.