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Implement tail calls in the middle of functions and allow recomping libgcc math routines (#43)

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Anghelo Carvajal 2024-05-14 18:56:23 -04:00 committed by GitHub
parent 5d46de6de0
commit 26c5c2cbb8
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GPG key ID: B5690EEEBB952194
3 changed files with 77 additions and 47 deletions
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1
.gitignore vendored
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@ -1,5 +1,6 @@
# VSCode file settings
.vscode/settings.json
.vscode/c_cpp_properties.json
# Input elf and rom files
*.elf

18
src/main.cpp
View file

@ -500,14 +500,7 @@ std::unordered_set<std::string> ignored_funcs {
"rmonGetRcpRegister",
"kdebugserver",
"send",
// libgcc math routines (these throw off the recompiler)
"__muldi3",
"__divdi3",
"__udivdi3",
"__umoddi3",
"div64_64",
"div64_32",
"__moddi3",
// ido math routines
"__ll_div",
"__ll_lshift",
@ -626,6 +619,15 @@ std::unordered_set<std::string> renamed_funcs{
"clear_bufs",
"fill_inbuf",
"flush_window",
// libgcc math routines
"__muldi3",
"__divdi3",
"__udivdi3",
"__umoddi3",
"div64_64",
"div64_32",
"__moddi3",
};
bool read_symbols(RecompPort::Context& context, const ELFIO::elfio& elf_file, ELFIO::section* symtab_section, uint32_t entrypoint, bool has_entrypoint, bool use_absolute_symbols) {

105
src/recompilation.cpp
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@ -47,6 +47,8 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
uint32_t reloc_section = 0;
uint32_t reloc_target_section_offset = 0;
uint32_t func_vram_end = func.vram + func.words.size() * sizeof(func.words[0]);
// Check if this instruction has a reloc.
if (section.relocatable && section.relocs.size() > 0 && section.relocs[reloc_index].address == instr_vram) {
// Get the reloc data for this instruction
@ -104,27 +106,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
}
};
auto print_branch = [&]<typename... Ts>(fmt::format_string<Ts...> fmt_str, Ts ...args) {
fmt::print(output_file, "{{\n ");
if (instr_index < instructions.size() - 1) {
bool dummy_needs_link_branch;
bool dummy_is_branch_likely;
size_t next_reloc_index = reloc_index;
uint32_t next_vram = instr_vram + 4;
if (reloc_index + 1 < section.relocs.size() && next_vram > section.relocs[reloc_index].address) {
next_reloc_index++;
}
process_instruction(context, config, func, stats, skipped_insns, instr_index + 1, instructions, output_file, true, false, link_branch_index, next_reloc_index, dummy_needs_link_branch, dummy_is_branch_likely, static_funcs_out);
}
fmt::print(output_file, " ");
fmt::vprint(output_file, fmt_str, fmt::make_format_args(args...));
if (needs_link_branch) {
fmt::print(output_file, ";\n goto after_{}", link_branch_index);
}
fmt::print(output_file, ";\n }}\n");
};
auto print_func_call = [&](uint32_t target_func_vram) {
auto print_func_call = [&](uint32_t target_func_vram, bool link_branch = true) {
const auto matching_funcs_find = context.functions_by_vram.find(target_func_vram);
std::string jal_target_name;
uint32_t section_vram_start = section.ram_addr;
@ -190,11 +172,46 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
return false;
}
}
needs_link_branch = true;
needs_link_branch = link_branch;
print_unconditional_branch("{}(rdram, ctx)", jal_target_name);
return true;
};
auto print_branch = [&](uint32_t branch_target) {
if (branch_target < func.vram || branch_target >= func_vram_end) {
// FIXME: how to deal with static functions?
if (context.functions_by_vram.find(branch_target) != context.functions_by_vram.end()) {
fmt::print(output_file, "{{\n ");
fmt::print("Tail call in {} to 0x{:08X}\n", func.name, branch_target);
print_func_call(branch_target, false);
print_line("return");
fmt::print(output_file, ";\n }}\n");
return;
}
fmt::print(stderr, "[Warn] Function {} is branching outside of the function (to 0x{:08X})\n", func.name, branch_target);
}
fmt::print(output_file, "{{\n ");
if (instr_index < instructions.size() - 1) {
bool dummy_needs_link_branch;
bool dummy_is_branch_likely;
size_t next_reloc_index = reloc_index;
uint32_t next_vram = instr_vram + 4;
if (reloc_index + 1 < section.relocs.size() && next_vram > section.relocs[reloc_index].address) {
next_reloc_index++;
}
process_instruction(context, config, func, stats, skipped_insns, instr_index + 1, instructions, output_file, true, false, link_branch_index, next_reloc_index, dummy_needs_link_branch, dummy_is_branch_likely, static_funcs_out);
}
fmt::print(output_file, " ");
fmt::print(output_file, "goto L_{:08X}", branch_target);
if (needs_link_branch) {
fmt::print(output_file, ";\n goto after_{}", link_branch_index);
}
fmt::print(output_file, ";\n }}\n");
};
if (indent) {
print_indent();
}
@ -216,8 +233,6 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
std::string unsigned_imm_string;
std::string signed_imm_string;
uint32_t func_vram_end = func.vram + func.words.size() * sizeof(func.words[0]);
if (!at_reloc) {
unsigned_imm_string = fmt::format("{:#X}", imm);
signed_imm_string = fmt::format("{:#X}", (int16_t)imm);
@ -492,7 +507,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_swr:
print_line("do_swr(rdram, {}, {}{}, {}{})", signed_imm_string, ctx_gpr_prefix(base), base, ctx_gpr_prefix(rt), rt);
break;
// Branches
case InstrId::cpu_jal:
print_func_call(instr.getBranchVramGeneric());
@ -511,16 +526,28 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
{
uint32_t branch_target = instr.getBranchVramGeneric();
if (branch_target == instr_vram) {
print_line("void pause_self(uint8_t *rdram); pause_self(rdram)");
print_line("pause_self(rdram)");
}
// Check if the branch is within this function
else if (branch_target >= func.vram && branch_target < func_vram_end) {
print_unconditional_branch("goto L_{:08X}", branch_target);
}
// Otherwise, check if it's a tail call
else if (instr_vram == func_vram_end - 2 * sizeof(func.words[0])) {
fmt::print("Tail call in {}\n", func.name);
print_func_call(branch_target);
// This may be a tail call in the middle of the control flow due to a previous check
// For example:
// ```c
// void test() {
// if (SOME_CONDITION) {
// do_a();
// } else {
// do_b();
// }
// }
// ```
// FIXME: how to deal with static functions?
else if (context.functions_by_vram.find(branch_target) != context.functions_by_vram.end()) {
fmt::print("Tail call in {} to 0x{:08X}\n", func.name, branch_target);
print_func_call(branch_target, false);
print_line("return");
}
else {
fmt::print(stderr, "Unhandled branch in {} at 0x{:08X} to 0x{:08X}\n", func.name, instr_vram, branch_target);
@ -536,7 +563,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
[instr_vram](const RecompPort::JumpTable& jtbl) {
return jtbl.jr_vram == instr_vram;
});
if (jtbl_find_result != stats.jump_tables.end()) {
const RecompPort::JumpTable& cur_jtbl = *jtbl_find_result;
bool dummy_needs_link_branch, dummy_is_branch_likely;
@ -593,7 +620,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bne:
print_indent();
print_branch_condition("if ({}{} != {}{})", ctx_gpr_prefix(rs), rs, ctx_gpr_prefix(rt), rt);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_beql:
is_branch_likely = true;
@ -601,7 +628,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_beq:
print_indent();
print_branch_condition("if ({}{} == {}{})", ctx_gpr_prefix(rs), rs, ctx_gpr_prefix(rt), rt);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_bgezl:
is_branch_likely = true;
@ -609,7 +636,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bgez:
print_indent();
print_branch_condition("if (SIGNED({}{}) >= 0)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_bgtzl:
is_branch_likely = true;
@ -617,7 +644,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bgtz:
print_indent();
print_branch_condition("if (SIGNED({}{}) > 0)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_blezl:
is_branch_likely = true;
@ -625,7 +652,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_blez:
print_indent();
print_branch_condition("if (SIGNED({}{}) <= 0)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_bltzl:
is_branch_likely = true;
@ -633,7 +660,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bltz:
print_indent();
print_branch_condition("if (SIGNED({}{}) < 0)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_break:
print_line("do_break({})", instr_vram);
@ -814,7 +841,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bc1t:
print_indent();
print_branch_condition("if (c1cs)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
case InstrId::cpu_bc1fl:
is_branch_likely = true;
@ -822,7 +849,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C
case InstrId::cpu_bc1f:
print_indent();
print_branch_condition("if (!c1cs)", ctx_gpr_prefix(rs), rs);
print_branch("goto L_{:08X}", (uint32_t)instr.getBranchVramGeneric());
print_branch((uint32_t)instr.getBranchVramGeneric());
break;
// Cop1 arithmetic