From 1547a2d3394d7ec87350ab8ca4022d5e0f20db01 Mon Sep 17 00:00:00 2001 From: Taylor Simpson Date: Mon, 15 Jan 2024 15:14:41 -0700 Subject: Hexagon (target/hexagon) Use QEMU decodetree (32-bit instructions) The Decodetree Specification can be found here https://www.qemu.org/docs/master/devel/decodetree.html Covers all 32-bit instructions, including HVX We generate separate decoders for each instruction class. The reason will be more apparent in the next patch in this series. We add 2 new scripts gen_decodetree.py Generate the input to decodetree.py gen_trans_funcs.py Generate the trans_* functions used by the output of decodetree.py Since the functions generated by decodetree.py take DisasContext * as an argument, we add the argument to a couple of functions that didn't need it previously. We also set the insn field in DisasContext during decode because it is used by the trans_* functions. There is a g_assert_not_reached() in decode_insns() in decode.c to verify we never try to use the old decoder on 32-bit instructions Signed-off-by: Taylor Simpson Reviewed-by: Brian Cain Message-Id: <20240115221443.365287-2-ltaylorsimpson@gmail.com> Signed-off-by: Brian Cain --- target/hexagon/README | 13 ++- target/hexagon/decode.c | 54 +++++++++-- target/hexagon/decode.h | 5 +- target/hexagon/gen_decodetree.py | 190 ++++++++++++++++++++++++++++++++++++++ target/hexagon/gen_trans_funcs.py | 132 ++++++++++++++++++++++++++ target/hexagon/meson.build | 55 +++++++++++ target/hexagon/translate.c | 4 +- 7 files changed, 439 insertions(+), 14 deletions(-) create mode 100755 target/hexagon/gen_decodetree.py create mode 100755 target/hexagon/gen_trans_funcs.py diff --git a/target/hexagon/README b/target/hexagon/README index 69b2ffe..1b2a4d0 100644 --- a/target/hexagon/README +++ b/target/hexagon/README @@ -189,11 +189,16 @@ the packet, and we mark the implicit writes. After the analysis is performed, we initialize the result register for each of the predicated assignments. In addition to instruction semantics, we use a generator to create the decode -tree. This generation is also a two step process. The first step is to run -target/hexagon/gen_dectree_import.c to produce +tree. This generation is a four step process. +Step 1 is to run target/hexagon/gen_dectree_import.c to produce /target/hexagon/iset.py -This file is imported by target/hexagon/dectree.py to produce - /target/hexagon/dectree_generated.h.inc +Step 2 is to import iset.py into target/hexagon/gen_decodetree.py to produce + /target/hexagon/normal_decode_generated + /target/hexagon/hvx_decode_generated +Step 3 is to process the above files with QEMU's decodetree.py to produce + /target/hexagon/decode_*_generated.c.inc +Step 4 is to import iset.py into target/hexagon/gen_trans_funcs.py to produce + /target/hexagon/decodetree_trans_funcs_generated.c.inc *** Key Files *** diff --git a/target/hexagon/decode.c b/target/hexagon/decode.c index 946c55c..bddad1f 100644 --- a/target/hexagon/decode.c +++ b/target/hexagon/decode.c @@ -52,6 +52,34 @@ DEF_REGMAP(R_8, 8, 0, 1, 2, 3, 4, 5, 6, 7) #define DECODE_MAPPED_REG(OPNUM, NAME) \ insn->regno[OPNUM] = DECODE_REGISTER_##NAME[insn->regno[OPNUM]]; +/* Helper functions for decode_*_generated.c.inc */ +#define DECODE_MAPPED(NAME) \ +static int decode_mapped_reg_##NAME(DisasContext *ctx, int x) \ +{ \ + return DECODE_REGISTER_##NAME[x]; \ +} +DECODE_MAPPED(R_16) +DECODE_MAPPED(R_8) + +/* Helper function for decodetree_trans_funcs_generated.c.inc */ +static int shift_left(DisasContext *ctx, int x, int n, int immno) +{ + int ret = x; + Insn *insn = ctx->insn; + if (!insn->extension_valid || + insn->which_extended != immno) { + ret <<= n; + } + return ret; +} + +/* Include the generated decoder for 32 bit insn */ +#include "decode_normal_generated.c.inc" +#include "decode_hvx_generated.c.inc" + +/* Include the generated helpers for the decoder */ +#include "decodetree_trans_funcs_generated.c.inc" + typedef struct { const struct DectreeTable *table_link; const struct DectreeTable *table_link_b; @@ -550,7 +578,8 @@ apply_extender(Packet *pkt, int i, uint32_t extender) int immed_num; uint32_t base_immed; - immed_num = opcode_which_immediate_is_extended(pkt->insn[i].opcode); + immed_num = pkt->insn[i].which_extended; + g_assert(immed_num == opcode_which_immediate_is_extended(pkt->insn[i].opcode)); base_immed = pkt->insn[i].immed[immed_num]; pkt->insn[i].immed[immed_num] = extender | fZXTN(6, 32, base_immed); @@ -762,12 +791,19 @@ decode_insns_tablewalk(Insn *insn, const DectreeTable *table, } static unsigned int -decode_insns(Insn *insn, uint32_t encoding) +decode_insns(DisasContext *ctx, Insn *insn, uint32_t encoding) { const DectreeTable *table; if (parse_bits(encoding) != 0) { + if (decode_normal(ctx, encoding) || + decode_hvx(ctx, encoding)) { + insn->generate = opcode_genptr[insn->opcode]; + insn->iclass = iclass_bits(encoding); + return 1; + } /* Start with PP table - 32 bit instructions */ table = &dectree_table_DECODE_ROOT_32; + g_assert_not_reached(); } else { /* start with EE table - duplex instructions */ table = &dectree_table_DECODE_ROOT_EE; @@ -916,8 +952,8 @@ decode_set_slot_number(Packet *pkt) * or number of words used on success */ -int decode_packet(int max_words, const uint32_t *words, Packet *pkt, - bool disas_only) +int decode_packet(DisasContext *ctx, int max_words, const uint32_t *words, + Packet *pkt, bool disas_only) { int num_insns = 0; int words_read = 0; @@ -930,9 +966,11 @@ int decode_packet(int max_words, const uint32_t *words, Packet *pkt, memset(pkt, 0, sizeof(*pkt)); /* Try to build packet */ while (!end_of_packet && (words_read < max_words)) { + Insn *insn = &pkt->insn[num_insns]; + ctx->insn = insn; encoding32 = words[words_read]; end_of_packet = is_packet_end(encoding32); - new_insns = decode_insns(&pkt->insn[num_insns], encoding32); + new_insns = decode_insns(ctx, insn, encoding32); g_assert(new_insns > 0); /* * If we saw an extender, mark next word extended so immediate @@ -1006,9 +1044,13 @@ int decode_packet(int max_words, const uint32_t *words, Packet *pkt, int disassemble_hexagon(uint32_t *words, int nwords, bfd_vma pc, GString *buf) { + DisasContext ctx; Packet pkt; - if (decode_packet(nwords, words, &pkt, true) > 0) { + memset(&ctx, 0, sizeof(DisasContext)); + ctx.pkt = &pkt; + + if (decode_packet(&ctx, nwords, words, &pkt, true) > 0) { snprint_a_pkt_disas(buf, &pkt, words, pc); return pkt.encod_pkt_size_in_bytes; } else { diff --git a/target/hexagon/decode.h b/target/hexagon/decode.h index c66f5ea..3f3012b 100644 --- a/target/hexagon/decode.h +++ b/target/hexagon/decode.h @@ -21,12 +21,13 @@ #include "cpu.h" #include "opcodes.h" #include "insn.h" +#include "translate.h" void decode_init(void); void decode_send_insn_to(Packet *packet, int start, int newloc); -int decode_packet(int max_words, const uint32_t *words, Packet *pkt, - bool disas_only); +int decode_packet(DisasContext *ctx, int max_words, const uint32_t *words, + Packet *pkt, bool disas_only); #endif diff --git a/target/hexagon/gen_decodetree.py b/target/hexagon/gen_decodetree.py new file mode 100755 index 0000000..9634554 --- /dev/null +++ b/target/hexagon/gen_decodetree.py @@ -0,0 +1,190 @@ +#!/usr/bin/env python3 + +## +## Copyright (c) 2024 Taylor Simpson +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 2 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program; if not, see . +## + +import io +import re + +import sys +import textwrap +import iset +import hex_common + +encs = { + tag: "".join(reversed(iset.iset[tag]["enc"].replace(" ", ""))) + for tag in iset.tags + if iset.iset[tag]["enc"] != "MISSING ENCODING" +} + + +regre = re.compile(r"((? 1: + raise Exception(f"{tag} has split register field!") + reg_enc_field = reg_enc_fields[0] + if 2 ** len(reg_enc_field) != reg_num_choices: + raise Exception(f"{tag} has incorrect register field width!") + + f.write(f"%{tag}_{reg_type}{reg_id}\t" + f"{enc.index(reg_enc_field)}:{len(reg_enc_field)}") + + if (reg_type in num_registers and + reg_num_choices != num_registers[reg_type]): + f.write(f"\t!function=decode_mapped_reg_{reg_mapping}") + f.write("\n") + + # Write the field definitions for the immediates + for imm in imms: + immno = 1 if imm[0].isupper() else 0 + imm_type = imm[0] + imm_width = int(imm[1]) + imm_letter = "i" if imm_type.islower() else "I" + fields = [] + sign_mark = "s" if imm_type.lower() in "sr" else "" + for m in reversed(list(re.finditer(imm_letter + "+", enc))): + fields.append(f"{m.start()}:{sign_mark}{m.end() - m.start()}") + sign_mark = "" + field_str = " ".join(fields) + f.write(f"%{tag}_{imm_type}{imm_letter}\t{field_str}\n") + + ## Handle instructions with unused encoding letters + ## Change the unused letters to ignored + if tag in tags_with_unused_d_encoding: + enc_str = enc_str.replace("d", "-") + if tag in tags_with_unused_t_encoding: + enc_str = enc_str.replace("t", "-") + + # Replace the operand letters with . + for x in operand_letters: + enc_str = enc_str.replace(x, ".") + + # Write the instruction format + f.write(f"@{tag}\t{enc_str}") + for reg in regs: + reg_type = reg[0] + reg_id = reg[1] + f.write(f" {reg_type}{reg_id}=%{tag}_{reg_type}{reg_id}") + for imm in imms: + imm_type = imm[0] + imm_letter = "i" if imm_type.islower() else "I" + f.write(f" {imm_type}{imm_letter}=%{tag}_{imm_type}{imm_letter}") + + f.write(" %PP\n") + + # Replace the 0s and 1s with . + enc_str = enc_str.replace("0", ".").replace("1", ".") + + # Write the instruction pattern + f.write(f"{tag}\t{enc_str} @{tag}\n") + + +if __name__ == "__main__": + hex_common.read_semantics_file(sys.argv[1]) + class_to_decode = sys.argv[2] + with open(sys.argv[3], "w") as f: + gen_decodetree_file(f, class_to_decode) diff --git a/target/hexagon/gen_trans_funcs.py b/target/hexagon/gen_trans_funcs.py new file mode 100755 index 0000000..c907131 --- /dev/null +++ b/target/hexagon/gen_trans_funcs.py @@ -0,0 +1,132 @@ +#!/usr/bin/env python3 + +## +## Copyright (c) 2024 Taylor Simpson +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 2 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program; if not, see . +## + +import io +import re + +import sys +import textwrap +import iset +import hex_common + +encs = { + tag: "".join(reversed(iset.iset[tag]["enc"].replace(" ", ""))) + for tag in iset.tags + if iset.iset[tag]["enc"] != "MISSING ENCODING" +} + + +regre = re.compile(r"((?which_extended = {0 if letter.islower() else 1}; + """)) + +## +## Generate the QEMU decodetree trans_ function for each instruction +## For A2_add: Rd32=add(Rs32,Rt32) +## We produce: +## static bool trans_A2_add(DisasContext *ctx, arg_A2_add *args) +## { +## Insn *insn = ctx->insn; +## insn->opcode = A2_add; +## insn->regno[0] = args->Rd; +## insn->regno[1] = args->Rs; +## insn->regno[2] = args->Rt; +## return true; +## } +## +def gen_trans_funcs(f, classes): + f.write(f"/* DO NOT MODIFY - This file is generated by {sys.argv[0]} */\n\n") + for tag in sorted(encs.keys(), key=iset.tags.index): + if skip_tag(tag, classes): + continue + + regs = ordered_unique(regre.findall(iset.iset[tag]["syntax"])) + imms = ordered_unique(immre.findall(iset.iset[tag]["syntax"])) + + f.write(textwrap.dedent(f"""\ + static bool trans_{tag}(DisasContext *ctx, arg_{tag} *args) + {open_curly} + Insn *insn = ctx->insn; + insn->opcode = {tag}; + """)) + + regno = 0 + for reg in regs: + reg_type = reg[0] + reg_id = reg[1] + f.write(code_fmt(f"""\ + insn->regno[{regno}] = args->{reg_type}{reg_id}; + """)) + regno += 1 + + if len(imms) != 0: + mark_which_imm_extended(f, tag) + + for imm in imms: + imm_type = imm[0] + imm_letter = "i" if imm_type.islower() else "I" + immno = 0 if imm_type.islower() else 1 + imm_shift = int(imm[2]) if imm[2] else 0 + if imm_shift: + f.write(code_fmt(f"""\ + insn->immed[{immno}] = + shift_left(ctx, args->{imm_type}{imm_letter}, + {imm_shift}, {immno}); + """)) + else: + f.write(code_fmt(f"""\ + insn->immed[{immno}] = args->{imm_type}{imm_letter}; + """)) + + f.write(textwrap.dedent(f"""\ + return true; + {close_curly} + """)) + + +if __name__ == "__main__": + hex_common.read_semantics_file(sys.argv[1]) + with open(sys.argv[2], "w") as f: + gen_trans_funcs(f, { "NORMAL", "EXT_mmvec" }) diff --git a/target/hexagon/meson.build b/target/hexagon/meson.build index da8e608..831bd57 100644 --- a/target/hexagon/meson.build +++ b/target/hexagon/meson.build @@ -133,6 +133,61 @@ dectree_generated = custom_target( ) hexagon_ss.add(dectree_generated) +# +# Generate the input to the QEMU decodetree.py script +# +normal_decode_generated = custom_target( + 'normal_decode_generated', + output: 'normal_decode_generated', + depends: [iset_py, semantics_generated], + env: {'PYTHONPATH': meson.current_build_dir()}, + command: [python, files('gen_decodetree.py'), semantics_generated, 'NORMAL', '@OUTPUT@'], +) +hexagon_ss.add(normal_decode_generated) + +hvx_decode_generated = custom_target( + 'hvx_decode_generated', + output: 'hvx_decode_generated', + depends: [iset_py, semantics_generated], + env: {'PYTHONPATH': meson.current_build_dir()}, + command: [python, files('gen_decodetree.py'), semantics_generated, 'EXT_mmvec', '@OUTPUT@'], +) +hexagon_ss.add(hvx_decode_generated) + +# +# Run the QEMU decodetree.py script to produce the instruction decoder +# +decodetree_py = meson.current_source_dir() / '../../scripts/decodetree.py' +decode_normal_generated = custom_target( + 'decode_normal_generated.c.inc', + output: 'decode_normal_generated.c.inc', + input: normal_decode_generated, + env: {'PYTHONPATH': meson.current_build_dir()}, + command: [python, files(decodetree_py), normal_decode_generated, '--static-decode=decode_normal', '-o', '@OUTPUT@'], +) +hexagon_ss.add(decode_normal_generated) + +decode_hvx_generated = custom_target( + 'decode_hvx_generated.c.inc', + output: 'decode_hvx_generated.c.inc', + input: hvx_decode_generated, + env: {'PYTHONPATH': meson.current_build_dir()}, + command: [python, files(decodetree_py), hvx_decode_generated, '--static-decode=decode_hvx', '-o', '@OUTPUT@'], +) +hexagon_ss.add(decode_hvx_generated) + +# +# Generate the trans_* functions that the decoder will use +# +decodetree_trans_funcs_generated = custom_target( + 'decodetree_trans_funcs_generated.c.inc', + output: 'decodetree_trans_funcs_generated.c.inc', + depends: [iset_py, semantics_generated], + env: {'PYTHONPATH': meson.current_build_dir()}, + command: [python, files('gen_trans_funcs.py'), semantics_generated, '@OUTPUT@'], +) +hexagon_ss.add(decodetree_trans_funcs_generated) + hexagon_ss.add(files( 'cpu.c', 'translate.c', diff --git a/target/hexagon/translate.c b/target/hexagon/translate.c index 666c061..95579ae 100644 --- a/target/hexagon/translate.c +++ b/target/hexagon/translate.c @@ -1033,10 +1033,10 @@ static void decode_and_translate_packet(CPUHexagonState *env, DisasContext *ctx) return; } - if (decode_packet(nwords, words, &pkt, false) > 0) { + ctx->pkt = &pkt; + if (decode_packet(ctx, nwords, words, &pkt, false) > 0) { pkt.pc = ctx->base.pc_next; HEX_DEBUG_PRINT_PKT(&pkt); - ctx->pkt = &pkt; gen_start_packet(ctx); for (i = 0; i < pkt.num_insns; i++) { ctx->insn = &pkt.insn[i]; -- cgit v1.1