Add the LP64E ABI, to support RV64E #299
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This is just a quick copy of ILP32E, not sure if I missed something. Signed-off-by: Palmer Dabbelt <[email protected]>
| IMPORTANT: RV32E and RV64E are not ratified base ISAs and so we cannot | ||
| guarantee the stability of ILP32E or LP64E, in contrast with the rest of this | ||
| document. This documents the current ILP32E implementation in GCC as of the | ||
| time of writing, but may be subject to change. |
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| IMPORTANT: RV32E and RV64E are not ratified base ISAs and so we cannot | |
| guarantee the stability of ILP32E or LP64E, in contrast with the rest of this | |
| document. This documents the current ILP32E implementation in GCC as of the | |
| time of writing, but may be subject to change. | |
| IMPORTANT: RV32E and RV64E are not ratified base ISAs and so we cannot | |
| guarantee their stability, in contrast with the rest of this | |
| document. This documents the current ILP32E implementation in GCC as of the | |
| time of writing, but may be subject to change. |
| the following differences. The stack pointer need only be aligned to a 32-bit | ||
| boundary. | ||
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| The LP64E calling convention is designed to be usable with the RV32E ISA. This |
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| The LP64E calling convention is designed to be usable with the RV32E ISA. This | |
| The LP64E calling convention is designed to be usable with the RV64E ISA. This |
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Generally LGTM, but this will pending until 1.0 release :) |
| @@ -246,17 +246,24 @@ provided they hold values no more than FLEN bits wide. | |||
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| === ILP32E Calling Convention | |||
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| === ILP32E Calling Convention | |
| === ILP32E and LP64E Calling Conventions |
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Quick drive-by comment: The sentence "Tag_RISCV_stack_align records the N-byte stack alignment for this object. The default value is 16 for RV32I or RV64I, and 4 for RV32E." in riscv-elf.adoc should be expanded to cover RV64E. |
Thanks. I guess it'd be 8-byte aligned for RV64E, as that's the same tradeoff we made for RV32E (ie, penalize Q in favor of everything else). Did the RV64E stuff actually happen? The original announcement was kind of weird, I'm not sure if it was on purpose. |
Per the recently ratified extension list it was ratified in January, so it looks like it's official, opening the question of what's next for the RV32E and RV64E ABIs! |
I guess we should probably get this finished, then. Have you guys had any interest in RV64E on the LLVM side of things? |
I've been giving some guidance to a colleague who saw it was a gap vs the ratified extensions and thought it might be interesting to sort it (initially just RV64E at the MC/assembler layer). But no external demand. |
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Since RV32E and RV64E are ratified and psABI 1.0 is already released, I think it's a good time to merge this. Also, we should move forward to ratify ILP32E and LP64E ABIs. |
| IMPORTANT: RV32E and RV64E are not ratified base ISAs and so we cannot | ||
| guarantee the stability of ILP32E or LP64E, in contrast with the rest of this | ||
| document. This documents the current ILP32E implementation in GCC as of the | ||
| time of writing, but may be subject to change. |
There was a problem hiding this comment.
| IMPORTANT: RV32E and RV64E are not ratified base ISAs and so we cannot | |
| guarantee the stability of ILP32E or LP64E, in contrast with the rest of this | |
| document. This documents the current ILP32E implementation in GCC as of the | |
| time of writing, but may be subject to change. |
Since RV32E and RV64E are ratified, this section is no longer necessary.
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RV32E and RV64E are ratified, but we shouldn't instantly mark ILP32E and LP64E as being finalised. For instance, it looks like we don't properly document the alignment on ILP32E for 2xlen types - where I believe only on the stack these types are 4-byte aligned in GCC? (The note about the stack being 4-byte aligned and the D extension not being compatible is relevant - but you could have a 4 byte stack and require it to be realigned for stack objects that need greater alignment).
Along with RV32E, RV64E is ratified. Though ILP32E and LP64E ABIs are still draft, it's worth supporting it. This commit should not be merged until two proposals below are going to proceed. LP64E proposal (including suggested changes): <riscv-non-isa/riscv-elf-psabi-doc#299> New "__riscv_64e" proposal by the author of this commit: <riscv-non-isa/riscv-c-api-doc#52> gcc/ChangeLog: * common/config/riscv/riscv-common.cc (riscv_subset_list::parse_std_ext): Allow RV64E. * config.gcc: Parse base ISA RV64E and ABI LP64E. * config/riscv/arch-canonicalize: Parse base ISA 'rv64e'. * config/riscv/riscv-c.cc (riscv_cpu_cpp_builtins): Build different macro per RV32E/RV64E. Add handling for ABI_LP64E. * config/riscv/riscv-d.cc (riscv_d_handle_target_float_abi): Add handling for ABI_LP64E. * config/riscv/riscv-opts.h (enum riscv_abi_type): Add ABI_LP64E. * config/riscv/riscv.cc (riscv_option_override): Enhance error handling to support RV64E and LP64E. (riscv_conditional_register_usage): Change "RV32E" in a comment to "RV32E/RV64E". * config/riscv/riscv.h (UNITS_PER_FP_ARG): Add handling for ABI_LP64E. (STACK_BOUNDARY): Ditto. (ABI_STACK_BOUNDARY): Ditto. (MAX_ARGS_IN_REGISTERS): Ditto. (ABI_SPEC): Add support for "lp64e". * config/riscv/riscv.opt: Parse -mabi=lp64e as ABI_LP64E. * doc/invoke.texi: Add documentation of the LP64E ABI. gcc/testsuite/ChangeLog: * gcc.target/riscv/predef-1.c: Test for __riscv_64e. * gcc.target/riscv/predef-2.c: Ditto. * gcc.target/riscv/predef-3.c: Ditto. * gcc.target/riscv/predef-4.c: Ditto. * gcc.target/riscv/predef-5.c: Ditto. * gcc.target/riscv/predef-6.c: Ditto. * gcc.target/riscv/predef-7.c: Ditto. * gcc.target/riscv/predef-8.c: Ditto. * gcc.target/riscv/predef-9.c: New test for RV32E and LP64E, based on predef-7.c.
Along with RV32E, RV64E is ratified. Though ILP32E and LP64E ABIs are still draft, it's worth supporting it. This commit should not be merged until two proposals below are going to proceed. LP64E proposal (including suggested changes): <riscv-non-isa/riscv-elf-psabi-doc#299> New "__riscv_64e" proposal by the author of this commit: <riscv-non-isa/riscv-c-api-doc#52> gcc/ChangeLog: * common/config/riscv/riscv-common.cc (riscv_subset_list::parse_std_ext): Allow RV64E. * config.gcc: Parse base ISA 'rv64e' and ABI 'lp64e'. * config/riscv/arch-canonicalize: Parse base ISA 'rv64e'. * config/riscv/riscv-c.cc (riscv_cpu_cpp_builtins): Define different macro per XLEN. Add handling for ABI_LP64E. * config/riscv/riscv-d.cc (riscv_d_handle_target_float_abi): Add handling for ABI_LP64E. * config/riscv/riscv-opts.h (enum riscv_abi_type): Add ABI_LP64E. * config/riscv/riscv.cc (riscv_option_override): Enhance error handling to support RV64E and LP64E. (riscv_conditional_register_usage): Change "RV32E" in a comment to "RV32E/RV64E". * config/riscv/riscv.h (UNITS_PER_FP_ARG): Add handling for ABI_LP64E. (STACK_BOUNDARY): Ditto. (ABI_STACK_BOUNDARY): Ditto. (MAX_ARGS_IN_REGISTERS): Ditto. (ABI_SPEC): Add support for "lp64e". * config/riscv/riscv.opt: Parse -mabi=lp64e as ABI_LP64E. * doc/invoke.texi: Add documentation of the LP64E ABI. gcc/testsuite/ChangeLog: * gcc.target/riscv/predef-1.c: Test for __riscv_64e. * gcc.target/riscv/predef-2.c: Ditto. * gcc.target/riscv/predef-3.c: Ditto. * gcc.target/riscv/predef-4.c: Ditto. * gcc.target/riscv/predef-5.c: Ditto. * gcc.target/riscv/predef-6.c: Ditto. * gcc.target/riscv/predef-7.c: Ditto. * gcc.target/riscv/predef-8.c: Ditto. * gcc.target/riscv/predef-9.c: New test for RV64E and LP64E, based on predef-7.c.
This is just a quick copy of ILP32E, not sure if I missed something.
Signed-off-by: Palmer Dabbelt [email protected]