2011/10/28 Georg-Johann Lay <a...@gjlay.de>: > Georg-Johann Lay schrieb: > >> This patch adds named address space support to read data from flash (aka. >> progmem) to target AVR. >> >> The patch has two parts: >> >> The first part is a repost of Ulrich's work from >> http://gcc.gnu.org/ml/gcc/2011-08/msg00131.html >> with the needed changes to ./gcc and ./gcc/doc >> >> This patch is needed because the target hooks MODE_CODE_BASE_REG_CLASS and >> REGNO_MODE_CODE_OK_FOR_BASE_P don't distinguish between different address >> spaces. Ulrich's patch adds respective support to these hooks. >> >> The second part is the AVR dependent part that adds __pgm as address space >> qualifier for address space AS1. >> >> The AVR part is just the worker code. If there is agreement that AS support >> for AVR is okay in principle and Ulrich's work will go into GCC, I will >> supply >> test programs and updates to the user manual, of course. >> >> The major drawbacks of the current AS implementation are: >> >> - It works only for C. >> For C++, a language extension would be needed as indicated in >> ISO/IEC DTR 18037 >> Annex F - C++ Compatibility and Migration issues >> F.2 Multiple Address Spaces Support >> >> - Register allocation does not a good job. AS1 can only be addressed >> byte-wise by one single address register (Z) as per *Z or *Z++. > > This flaw from register allocator are filed as PR50775 now. > >> The AVR part does several things: >> >> - It locates data in AS1 into appropriate section, i.e. somewhere in >> .progmem >> >> - It does early sanity checks to ensure that __pgm is always accompanied >> with const so that writing to AS1 in not possible. >> >> - It prints LPM instructions to access flash memory. > > The attached patch is an update merge so that it fits without conflicts. > > The patch requires Ulrich's works which is still in review > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50775 > > The regression tests run with this patch and the new ChangeLog enttry si > written as if Ulrich's patch was applied. > > Tests pass without regression. > > Besides the update to a nor up-to-date SVN version, the patch sets a built-in > define __PGM so that it is easy for users to test if or if not the feature is > available. > > Documentation and test cases will follow in separate patch. > > Ok for trunk after Ulrich's work has been approved? > > Johann > > PR target/49868 > * config/avr/avr.h (ADDR_SPACE_PGM): New define for address space AS1. > (REGISTER_TARGET_PRAGMAS): New define. > * config/avr/avr-protos.h (avr_mem_pgm_p): New prototype. > (avr_register_target_pragmas): New prototype. > (avr_log_t): Add field "progmem". Order alphabetically. > * config/avr/avr-log.c (avr_log_set_avr_log): Set avr_log.progmem. > * config/avr/avr-c.c (langhooks.h): New include. > (avr_register_target_pragmas): New function. Register address > space AS1 as "__pgm". > (avr_cpu_cpp_builtins): Add built-in define __PGM. > * config/avr/avr.c: Include "c-family/c-common.h". > (TARGET_LEGITIMATE_ADDRESS_P): Remove define. > (TARGET_LEGITIMIZE_ADDRESS): Remove define. > (TARGET_ADDR_SPACE_SUBSET_P): Define to... > (avr_addr_space_subset_p): ...this new static function. > (TARGET_ADDR_SPACE_CONVERT): Define to... > (avr_addr_space_convert): ...this new static function. > (TARGET_ADDR_SPACE_ADDRESS_MODE): Define to... > (avr_addr_space_address_mode): ...this new static function. > (TARGET_ADDR_SPACE_POINTER_MODE): Define to... > (avr_addr_space_pointer_mode): ...this new static function. > (TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P): Define to... > (avr_addr_space_legitimate_address_p): ...this new static function. > (TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS): Define to... > (avr_addr_space_legitimize_address): ...this new static function. > (avr_mode_code_base_reg_class): Handle AS1. > (avr_regno_mode_code_ok_for_base_p): Handle AS1. > (lpm_addr_reg_rtx, lpm_reg_rtx): New static GTYed variables. > (avr_decl_pgm_p): New static function. > (avr_mem_pgm_p): New function. > (avr_asm_len): Return always "" instead of void. > (avr_out_lpm_no_lpmx): New static function. > (avr_out_lpm): New static function. > (output_movqi, output_movhi, output_movsisf): Call avr_out_lpm to > handle loads from progmem. > (avr_progmem_p): Test if decl is in AS1. > (avr_pgm_pointer_const_p): New static function. > (avr_pgm_check_var_decl): New static function. > (avr_insert_attributes): Use it. Change error message to report > cause (progmem or AS1) when code wants to write to AS1. > (avr_section_type_flags): Unset section flag SECTION_BSS for > data in progmem. > * config/avr/avr.md (LPM_REGNO): New define_constants. > (movqi, movhi, movsi, movsf): Skip if code would write to AS1. > (movmemhi): Ditto. Propagate address space information to newly > created MEM. > (split-lpmx): New split. >
Approved. Denis.
