From b94a6cf695191d96c6546b87710900cfbb419b52 Mon Sep 17 00:00:00 2001 From: angie Date: Tue, 14 May 2024 17:03:16 -0400 Subject: [PATCH] Implement tail calls handled by conditional branches --- src/main.cpp | 7 +++-- src/recompilation.cpp | 63 ++++++++++++++++++++++++++----------------- 2 files changed, 42 insertions(+), 28 deletions(-) diff --git a/src/main.cpp b/src/main.cpp index 88e11ae..6cb8fd2 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -501,10 +501,6 @@ std::unordered_set ignored_funcs { "kdebugserver", "send", - // libgcc math routines (these throw off the recompiler) - "__divdi3", - "__moddi3", - // ido math routines "__ll_div", "__ll_lshift", @@ -624,11 +620,14 @@ std::unordered_set renamed_funcs{ "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) { diff --git a/src/recompilation.cpp b/src/recompilation.cpp index 2a14cd8..474f72f 100644 --- a/src/recompilation.cpp +++ b/src/recompilation.cpp @@ -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 @@ -104,26 +106,6 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C } }; - auto print_branch = [&](uint32_t target_vram) { - 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}", target_vram); - 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, bool link_branch = true) { const auto matching_funcs_find = context.functions_by_vram.find(target_func_vram); std::string jal_target_name; @@ -195,6 +177,41 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C 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); @@ -519,7 +534,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C } // 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); + fmt::print("Tail call in {} to 0x{:08X}\n", func.name, branch_target); print_func_call(branch_target); } // This may be a tail call in the middle of the control flow due to a previous check @@ -535,7 +550,7 @@ bool process_instruction(const RecompPort::Context& context, const RecompPort::C // ``` // 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 {}\n", func.name); + fmt::print("Tail call in {} to 0x{:08X}\n", func.name, branch_target); print_func_call(branch_target, false); print_line("return"); }