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Rename gp to got in various places to better reflect what's actually going on

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This commit is contained in:
Ethan Lafrenais 2025-01-12 23:50:16 -05:00
parent 361568071a
commit 875ea3f584
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GPG key ID: 928A0136009E2745
3 changed files with 15 additions and 20 deletions
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2
include/recompiler/context.h
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@ -102,7 +102,7 @@ namespace N64Recomp {
bool executable = false; bool executable = false;
bool relocatable = false; // TODO is this needed? relocs being non-empty should be an equivalent check. bool relocatable = false; // TODO is this needed? relocs being non-empty should be an equivalent check.
bool has_mips32_relocs = false; bool has_mips32_relocs = false;
std::optional<uint32_t> gp_ram_addr = std::nullopt; std::optional<uint32_t> got_ram_addr = std::nullopt;
}; };
struct ReferenceSection { struct ReferenceSection {

29
src/analysis.cpp
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@ -57,7 +57,7 @@ using InstrId = rabbitizer::InstrId::UniqueId;
using RegId = rabbitizer::Registers::Cpu::GprO32; using RegId = rabbitizer::Registers::Cpu::GprO32;
bool analyze_instruction(const rabbitizer::InstructionCpu& instr, const N64Recomp::Function& func, N64Recomp::FunctionStats& stats, bool analyze_instruction(const rabbitizer::InstructionCpu& instr, const N64Recomp::Function& func, N64Recomp::FunctionStats& stats,
RegState reg_states[32], std::vector<RegState>& stack_states, bool is_gp_reg_defined) { RegState reg_states[32], std::vector<RegState>& stack_states, bool is_got_addr_defined) {
// Temporary register state for tracking the register being operated on // Temporary register state for tracking the register being operated on
RegState temp{}; RegState temp{};
@ -118,9 +118,9 @@ bool analyze_instruction(const rabbitizer::InstructionCpu& instr, const N64Recom
&& reg_states[rs].valid_got_loaded != reg_states[rt].valid_got_loaded) { && reg_states[rs].valid_got_loaded != reg_states[rt].valid_got_loaded) {
// `addu rd, rs, $gp` or `addu rd, $gp, rt` after valid GOT load, this is the last part of a position independent // `addu rd, rs, $gp` or `addu rd, $gp, rt` after valid GOT load, this is the last part of a position independent
// jump table call. Keep the register state intact. // jump table call. Keep the register state intact.
int valid_gp_loaded_reg = reg_states[rs].valid_got_loaded ? rs : rt; int valid_got_loaded_reg = reg_states[rs].valid_got_loaded ? rs : rt;
temp = reg_states[valid_gp_loaded_reg]; temp = reg_states[valid_got_loaded_reg];
} }
// Exactly one of the two addend register states should have a valid lui at this time // Exactly one of the two addend register states should have a valid lui at this time
else if (reg_states[rs].valid_lui != reg_states[rt].valid_lui) { else if (reg_states[rs].valid_lui != reg_states[rt].valid_lui) {
@ -212,13 +212,8 @@ bool analyze_instruction(const rabbitizer::InstructionCpu& instr, const N64Recom
temp.loaded_addend_reg = reg_states[base].prev_addend_reg; temp.loaded_addend_reg = reg_states[base].prev_addend_reg;
temp.loaded_addu_vram = reg_states[base].prev_addu_vram; temp.loaded_addu_vram = reg_states[base].prev_addu_vram;
temp.prev_got_offset = reg_states[base].prev_got_offset; temp.prev_got_offset = reg_states[base].prev_got_offset;
} else if (base == (int)RegId::GPR_O32_gp) { } else if (base == (int)RegId::GPR_O32_gp && is_got_addr_defined) {
// lw from the $gp register implies a read from the global offset table // lw from the $gp register implies a read from the global offset table
if (!is_gp_reg_defined) {
fmt::print(stderr, "Found $gp register usage in section without a defined $gp value at 0x{:08X} in {}\n",
instr.getVram(), func.name);
return false;
}
temp.prev_got_offset = imm; temp.prev_got_offset = imm;
temp.valid_got_offset = true; temp.valid_got_offset = true;
} }
@ -272,7 +267,7 @@ bool analyze_instruction(const rabbitizer::InstructionCpu& instr, const N64Recom
bool N64Recomp::analyze_function(const N64Recomp::Context& context, const N64Recomp::Function& func, bool N64Recomp::analyze_function(const N64Recomp::Context& context, const N64Recomp::Function& func,
const std::vector<rabbitizer::InstructionCpu>& instructions, N64Recomp::FunctionStats& stats) { const std::vector<rabbitizer::InstructionCpu>& instructions, N64Recomp::FunctionStats& stats) {
const Section* section = &context.sections[func.section_index]; const Section* section = &context.sections[func.section_index];
std::optional<uint32_t> gp_ram_addr = section->gp_ram_addr; std::optional<uint32_t> got_ram_addr = section->got_ram_addr;
// Create a state to track each register (r0 won't be used) // Create a state to track each register (r0 won't be used)
RegState reg_states[32] {}; RegState reg_states[32] {};
@ -281,20 +276,20 @@ bool N64Recomp::analyze_function(const N64Recomp::Context& context, const N64Rec
// Look for jump tables // Look for jump tables
// A linear search through the func won't be accurate due to not taking control flow into account, but it'll work for finding jtables // A linear search through the func won't be accurate due to not taking control flow into account, but it'll work for finding jtables
for (const auto& instr : instructions) { for (const auto& instr : instructions) {
if (!analyze_instruction(instr, func, stats, reg_states, stack_states, gp_ram_addr.has_value())) { if (!analyze_instruction(instr, func, stats, reg_states, stack_states, got_ram_addr.has_value())) {
return false; return false;
} }
} }
// Calculate absolute addresses for position-independent jump tables // Calculate absolute addresses for position-independent jump tables
if (gp_ram_addr.has_value()) { if (got_ram_addr.has_value()) {
uint32_t gp_rom_addr = gp_ram_addr.value() + func.rom - func.vram; uint32_t got_rom_addr = got_ram_addr.value() + func.rom - func.vram;
for (size_t i = 0; i < stats.jump_tables.size(); i++) { for (size_t i = 0; i < stats.jump_tables.size(); i++) {
JumpTable& cur_jtbl = stats.jump_tables[i]; JumpTable& cur_jtbl = stats.jump_tables[i];
if (cur_jtbl.got_offset.has_value()) { if (cur_jtbl.got_offset.has_value()) {
uint32_t got_word = byteswap(*reinterpret_cast<const uint32_t*>(&context.rom[gp_rom_addr + cur_jtbl.got_offset.value()])); uint32_t got_word = byteswap(*reinterpret_cast<const uint32_t*>(&context.rom[got_rom_addr + cur_jtbl.got_offset.value()]));
cur_jtbl.vram += (section->ram_addr + got_word); cur_jtbl.vram += (section->ram_addr + got_word);
} }
@ -329,10 +324,10 @@ bool N64Recomp::analyze_function(const N64Recomp::Context& context, const N64Rec
uint32_t rom_addr = vram + func.rom - func.vram; uint32_t rom_addr = vram + func.rom - func.vram;
uint32_t jtbl_word = byteswap(*reinterpret_cast<const uint32_t*>(&context.rom[rom_addr])); uint32_t jtbl_word = byteswap(*reinterpret_cast<const uint32_t*>(&context.rom[rom_addr]));
if (cur_jtbl.got_offset.has_value() && gp_ram_addr.has_value()) { if (cur_jtbl.got_offset.has_value() && got_ram_addr.has_value()) {
// Position independent jump tables have values that are offsets from $gp, // Position independent jump tables have values that are offsets from the GOT,
// convert those to absolute addresses // convert those to absolute addresses
jtbl_word += gp_ram_addr.value(); jtbl_word += got_ram_addr.value();
} }
// Check if the entry is a valid address in the current function // Check if the entry is a valid address in the current function

4
src/config.cpp
View file

@ -509,7 +509,7 @@ bool N64Recomp::Context::from_symbol_file(const std::filesystem::path& symbol_fi
std::optional<uint32_t> vram_addr = el["vram"].template value<uint32_t>(); std::optional<uint32_t> vram_addr = el["vram"].template value<uint32_t>();
std::optional<uint32_t> size = el["size"].template value<uint32_t>(); std::optional<uint32_t> size = el["size"].template value<uint32_t>();
std::optional<std::string> name = el["name"].template value<std::string>(); std::optional<std::string> name = el["name"].template value<std::string>();
std::optional<uint32_t> gp_ram_addr = el["gp"].template value<uint32_t>(); std::optional<uint32_t> got_ram_addr = el["got_address"].template value<uint32_t>();
if (!rom_addr.has_value() || !vram_addr.has_value() || !size.has_value() || !name.has_value()) { if (!rom_addr.has_value() || !vram_addr.has_value() || !size.has_value() || !name.has_value()) {
throw toml::parse_error("Section entry missing required field(s)", el.source()); throw toml::parse_error("Section entry missing required field(s)", el.source());
@ -522,7 +522,7 @@ bool N64Recomp::Context::from_symbol_file(const std::filesystem::path& symbol_fi
section.ram_addr = vram_addr.value(); section.ram_addr = vram_addr.value();
section.size = size.value(); section.size = size.value();
section.name = name.value(); section.name = name.value();
section.gp_ram_addr = gp_ram_addr; section.got_ram_addr = got_ram_addr;
section.executable = true; section.executable = true;
// Read functions for the section. // Read functions for the section.