jak-project/decompiler/analysis/variable_naming.cpp
Tyler Wilding 60db0e5ef9
deps: update fmt to latest version (#3403)
This updates `fmt` to the latest version and moves to just being a copy
of their repo to make updating easier (no editing their cmake / figuring
out which files to minimally include).

The motivation for this is now that we switched to C++ 20, there were a
ton of deprecated function usages that is going away in future compiler
versions. This gets rid of all those warnings.
2024-03-05 22:11:52 -05:00

1127 lines
34 KiB
C++

#include "variable_naming.h"
#include <set>
#include "reg_usage.h"
#include "common/log/log.h"
#include "decompiler/Function/Function.h"
#include "decompiler/IR2/Env.h"
#include "decompiler/util/DecompilerTypeSystem.h"
#include "fmt/core.h"
namespace decompiler {
namespace {
template <typename T>
std::string reg_to_string(const T& regs) {
std::string result;
for (auto reg : regs) {
result += reg.to_charp();
result += ' ';
}
return result;
}
} // namespace
/*!
* Allocate a new SSA variable for the given register.
* This should only be used to allocate the result of a non-phi instruction (a real instruction)
*/
VarSSA VarMapSSA::allocate(Register reg) {
Entry new_entry;
new_entry.reg = reg;
new_entry.entry_id = int(m_entries.size());
new_entry.var_id = get_next_var_id(reg);
VarSSA result(reg, new_entry.entry_id);
m_entries.push_back(new_entry);
return result;
}
/*!
* Allocate a new SSA variable for the given register as a result of a phi.
* This should only be used to allocate the result of a phi-function.
*/
VarSSA VarMapSSA::allocate_init_phi(Register reg, int block_id) {
Entry new_entry;
new_entry.reg = reg;
new_entry.entry_id = int(m_entries.size());
new_entry.var_id = -block_id;
VarSSA result(reg, new_entry.entry_id);
m_entries.push_back(new_entry);
return result;
}
/*!
* Get the next unused variable id for the given register.
*/
int VarMapSSA::get_next_var_id(Register reg) {
return ++m_reg_next_id[reg];
}
/*!
* Combine the two variables into one. The final name is:
* - B0, if either is B0
* - otherwise b's name.
*/
void VarMapSSA::merge(const VarSSA& var_a, const VarSSA& var_b) {
auto& a = m_entries.at(var_a.m_entry_id);
auto b = m_entries.at(var_b.m_entry_id);
ASSERT(a.reg == b.reg);
if (b.var_id == 0) {
// lg::print("Merge {} <- {}\n", to_string(var_b), to_string(var_a));
for (auto& entry : m_entries) {
if (entry.var_id == a.var_id && entry.reg == a.reg) {
entry.var_id = b.var_id;
}
}
a.var_id = b.var_id;
} else {
// lg::print("Merge {} <- {}\n", to_string(var_a), to_string(var_b));
for (auto& entry : m_entries) {
if (entry.var_id == b.var_id && entry.reg == b.reg) {
entry.var_id = a.var_id;
}
}
b.var_id = a.var_id;
}
}
void VarMapSSA::merge_reg(Register reg) {
for (auto& entry : m_entries) {
if (entry.reg == reg) {
entry.var_id = 0;
}
}
}
/*!
* Make all Bs A.
*/
void VarMapSSA::merge_to_first(const VarSSA& var_a, const VarSSA& var_b) {
auto& a = m_entries.at(var_a.m_entry_id);
auto b = m_entries.at(var_b.m_entry_id);
// lg::print("Merge-to-first {} <- {}\n", to_string(var_a), to_string(var_b));
ASSERT(a.reg == b.reg);
// for (auto& entry : m_entries) {
for (size_t i = 0; i < m_entries.size(); i++) {
auto& entry = m_entries.at(i);
if (entry.var_id == b.var_id && entry.reg == b.reg) {
// lg::print("remap extra {} var_id from {} to {}\n", i, entry.var_id, a.var_id);
entry.var_id = a.var_id;
} else {
// lg::print("no remap at {} (prev is {} {})\n", i, entry.reg.to_charp(), entry.var_id);
}
}
b.var_id = a.var_id;
}
std::string VarMapSSA::to_string(const VarSSA& var) const {
auto var_id = m_entries.at(var.m_entry_id).var_id;
if (var_id > 0) {
return fmt::format("{}-{}", var.m_reg.to_charp(), var_id);
} else {
return fmt::format("{}-B{}", var.m_reg.to_charp(), -var_id);
}
}
/*!
* Do these two SSA variables represent the same "program variable"
*/
bool VarMapSSA::same(const VarSSA& var_a, const VarSSA& var_b) const {
return var_a.m_reg == var_b.m_reg &&
m_entries.at(var_a.m_entry_id).var_id == m_entries.at(var_b.m_entry_id).var_id;
}
/*!
* Get program variable ID from an SSA variable.
*/
int VarMapSSA::var_id(const VarSSA& var) const {
return m_entries.at(var.m_entry_id).var_id;
}
/*!
* For a given register and map, remap using var_id = remap[var_id]
* For variables not in the map, set ID to INT32_MIN.
*
* This allows you to do a full remapping, without worrying new/old mappings aliasing part way
* through the remapping.
*/
void VarMapSSA::remap_reg(Register reg, const std::unordered_map<int, int>& remap) {
for (auto& entry : m_entries) {
if (entry.reg == reg) {
auto kv = remap.find(entry.var_id);
if (kv == remap.end()) {
entry.var_id = INT32_MIN;
} else {
entry.var_id = kv->second;
}
}
}
}
void VarMapSSA::debug_print_map() const {
for (auto& entry : m_entries) {
lg::print("[{:02d}] {} {}\n", entry.entry_id, entry.reg.to_charp(), entry.var_id);
}
}
std::string SSA::Phi::print(const VarMapSSA& var_map) const {
std::string result = var_map.to_string(dest);
result += " <- phi(";
for (auto& s : sources) {
result += var_map.to_string(s);
result += ' ';
}
if (!sources.empty()) {
result.pop_back();
}
result += ')';
return result;
}
std::string SSA::Ins::print(const VarMapSSA& var_map) const {
std::string result;
if (dst.has_value()) {
result += var_map.to_string(*dst) + " <- (";
} else {
result += "read(";
}
for (auto& s : src) {
result += var_map.to_string(s);
result += ' ';
}
if (!src.empty()) {
result.pop_back();
}
result += ')';
return result;
}
std::string SSA::Block::print(const VarMapSSA& var_map) const {
std::string result;
for (auto& phi : phis) {
result += " ";
result += phi.second.print(var_map);
result += '\n';
}
for (auto& i : ins) {
result += " ";
result += i.print(var_map);
result += '\n';
}
return result;
}
/*!
* Get the phi function that sets the initial value of the given register in this block
* If no phi function exists, it will be created.
*/
SSA::Phi& SSA::get_phi(int block, Register dest_reg) {
auto& phi_map = blocks.at(block).phis;
auto kv = phi_map.find(dest_reg);
if (kv == phi_map.end()) {
// printf("Allocate new get_phi for %s B%d\n", dest_reg.to_charp(), block);
auto dest_var = map.allocate_init_phi(dest_reg, block);
phi_map.insert(std::make_pair(dest_reg, dest_var));
}
return phi_map.at(dest_reg);
}
/*!
* Get the result (SSA variable) of the phi function that sets the value of the given register in
* this block. If there is no phi which sets this, creates one (empty)
*/
VarSSA SSA::get_phi_dest(int block, Register dest_reg) {
return get_phi(block, dest_reg).dest;
}
/*!
* Add a source SSA variable to the phi setting the initial value of dest reg at the top of the
* given block. If there is no phi which sets dest_reg, creates one.
*/
void SSA::add_source_to_phi(int block, Register dest_reg, const VarSSA& src_var) {
auto& phi = get_phi(block, dest_reg);
phi.sources.push_back(src_var);
}
namespace {
bool is_arg_reg(Register r) {
if (r.get_kind() == Reg::GPR) {
return r.get_gpr() >= Reg::A0 && r.get_gpr() <= Reg::T3;
} else {
return false;
}
}
int arg_reg_idx(Register r) {
ASSERT(is_arg_reg(r));
return (int)r.get_gpr() - (int)Reg::A0;
}
bool is_saved_reg(Register r) {
if (r.get_kind() == Reg::GPR) {
if (r.get_gpr() == Reg::GP) {
return true;
}
return r.get_gpr() >= Reg::S0 && r.get_gpr() <= Reg::S6;
} else {
return false;
}
}
bool is_possible_coloring_move(Register dst, Register src) {
if (is_arg_reg(src) && is_saved_reg(dst)) {
return true;
}
if (dst.get_kind() == Reg::FPR && dst.get_fpr() < 20 && is_arg_reg(src)) {
return true;
}
return false;
}
namespace {
int arg_count(const Function& f) {
if (f.type.arg_count() > 0) {
return f.type.arg_count() - 1;
} else {
return 0;
}
}
} // namespace
/*!
* Create a "really crude" SSA, as described in
* "Aycock and Horspool Simple Generation of Static Single-Assignment Form"
*
* Note - we do a few tricks to make this more efficient, inspired by "improvement 1", but
* implemented slightly differently. (I couldn't figure out how to efficiently implement their
* improvement 1). We also take advantage of precomputed register usage info to avoid creating
* totally useless phis that propagate unused values through to the end of the function.
*/
SSA make_rc_ssa(const Function& function, const RegUsageInfo& rui, const FunctionAtomicOps& ops) {
SSA ssa(rui.block_count());
bool got_not_arg_coloring = false;
for (int block_id = 0; block_id < rui.block_count(); block_id++) {
const auto& block = function.basic_blocks.at(block_id);
int start_op = ops.block_id_to_first_atomic_op.at(block_id);
int end_op = ops.block_id_to_end_atomic_op.at(block_id);
if (start_op == end_op) {
// later we rely on having > 0 ops in our block, so we must reject 0 size blocks.
if (block_id + 1 == rui.block_count()) {
// if it's the last block, just ignore it. The expression propagator will ignore it too,
// so the return value will safely make it to the end.
continue;
}
// otherwise give up. This is something that should be fixed upstream (#196).
throw std::runtime_error("Zero size blocks not yet supported");
}
// local map: current register names at the current op.
std::unordered_map<Register, VarSSA, Register::hash> current_regs;
// if we're block zero, write function arguments:
// initialize phis. this is only done on:
// - variables live out at the first op
// - variables read by the first op
// which should contain at least all live variables at the beginning of the block.
// this may accidentally add a phi for a variable that's dead at the block entry but is
// defined by the first op. This is no big deal, as it will be trivially eliminated later on.
const auto& start_op_info = rui.op.at(start_op);
const auto& start_op_op = ops.ops.at(start_op);
auto init_regs = start_op_info.live;
for (auto reg : start_op_op->read_regs()) {
if (reg.get_kind() == Reg::FPR || reg.get_kind() == Reg::GPR) {
init_regs.insert(reg);
}
}
for (auto reg : init_regs) {
// to avoid operator[]
auto it = current_regs.find(reg);
if (it != current_regs.end()) {
ASSERT(false);
it->second = ssa.get_phi_dest(block_id, reg);
} else {
current_regs.insert(std::make_pair(reg, ssa.get_phi_dest(block_id, reg)));
}
}
if (block_id == 0) {
SSA::Ins ins(-1);
for (int i = 0; i < arg_count(function); i++) {
auto dest_reg = Register::get_arg_reg(i);
auto it = current_regs.find(dest_reg);
if (it == current_regs.end()) {
current_regs.insert(std::make_pair(dest_reg, ssa.get_phi_dest(block_id, dest_reg)));
}
ins.src.push_back(current_regs.at(dest_reg));
}
ssa.blocks.at(block_id).ins.push_back(ins);
}
// loop over ops, creating and reading from variables as needed.
for (int op_id = start_op; op_id < end_op; op_id++) {
const auto& op = ops.ops.at(op_id);
SSA::Ins ssa_i(op_id);
if (block_id == 0 && !got_not_arg_coloring) {
got_not_arg_coloring = true;
auto as_set = dynamic_cast<const SetVarOp*>(op.get());
if (as_set) {
auto dst = as_set->dst().reg();
if ((as_set->src().kind() == SimpleExpression::Kind::GPR_TO_FPR ||
as_set->src().is_identity()) &&
as_set->src().get_arg(0).is_var()) {
auto src = as_set->src().get_arg(0).var().reg();
if (is_possible_coloring_move(dst, src) &&
rui.op.at(op_id).consumes.find(src) != rui.op.at(op_id).consumes.end()) {
// an integer argument going into a fpr for int->float conversion shouldn't
// be recognized as a coloring move.
if (function.type.arg_count() > 0) {
auto arg_idx = arg_reg_idx(src);
if (dst.get_kind() != Reg::FPR ||
function.type.get_arg(arg_idx) == TypeSpec("float")) {
ssa_i.is_arg_coloring_move = true;
if (dst.get_kind() == Reg::FPR) {
ssa_i.is_gpr_fpr_coloring_move = true;
}
got_not_arg_coloring = false;
}
}
}
}
}
}
auto as_set = dynamic_cast<const SetVarOp*>(op.get());
if (as_set) {
auto dst = as_set->dst().reg();
if (as_set->src().is_var() ||
(as_set->src().kind() == SimpleExpression::Kind::FPR_TO_GPR)) {
auto src = as_set->src().get_arg(0).var().reg();
auto& ri = rui.op.at(op_id);
if (ri.consumes.find(src) != ri.consumes.end() &&
ri.written_and_unused.find(dst) != ri.written_and_unused.end()) {
ssa_i.is_dead_set = true;
}
}
}
// todo - verify no duplicates here?
ASSERT(op->write_regs().size() <= 1);
// reads:
for (auto r : op->read_regs()) {
if (r.get_kind() == Reg::FPR || r.get_kind() == Reg::GPR) {
ssa_i.src.push_back(current_regs.at(r));
}
}
// writes:
if (!op->write_regs().empty()) {
auto w = op->write_regs().front();
if (w.get_kind() == Reg::FPR || w.get_kind() == Reg::GPR) {
auto var = ssa.map.allocate(w);
ssa_i.dst = var;
// avoid operator[] again
auto it = current_regs.find(w);
if (it != current_regs.end()) {
it->second = var;
} else {
current_regs.insert(std::make_pair(w, var));
}
}
}
ssa.blocks.at(block_id).ins.push_back(ssa_i);
}
// process succs:
// auto& end_op_info = rui.op.at(end_op - 1);
for (auto succ : {block.succ_branch, block.succ_ft}) {
if (succ != -1) {
auto first_op_in_succ_id = ops.block_id_to_first_atomic_op.at(succ);
const auto& first_op_info = rui.op.at(first_op_in_succ_id);
const auto& first_op = ops.ops.at(first_op_in_succ_id);
// these are the registers that will actually be used in the successor block.
RegSet regs;
for (auto& reg : first_op->read_regs()) {
regs.insert(reg);
}
for (auto& reg : first_op_info.live) {
if (std::find(first_op->write_regs().begin(), first_op->write_regs().end(), reg) ==
first_op->write_regs().end()) {
regs.insert(reg);
}
}
for (auto reg : regs) {
// only update phis for variables that are actually live at the next block.
if (reg.get_kind() == Reg::FPR || reg.get_kind() == Reg::GPR) {
ssa.add_source_to_phi(succ, reg, current_regs.at(reg));
}
}
/*
for (auto reg : end_op_info.live) {
// only update phis for variables that are actually live at the next block.
if (reg.get_kind() == Reg::FPR || reg.get_kind() == Reg::GPR) {
ssa.add_source_to_phi(succ, reg, current_regs.at(reg));
}
}
*/
}
}
}
return ssa;
}
} // namespace
std::string SSA::print() const {
std::string result;
for (int block_id = 0; block_id < int(blocks.size()); block_id++) {
result += fmt::format("B-{}\n", block_id);
result += blocks.at(block_id).print(map);
result += "\n";
}
return result;
}
/*!
* Merge all variables in the same register to the given register.
*/
void SSA::merge_reg_to_single_variable(Register reg) {
map.merge_reg(reg);
}
/*!
* Simplify the SSA while still keeping it in SSA form.
* This does only a single pass of simplifications and returns true if it made changes.
*/
bool SSA::simplify() {
bool changed = false;
for (auto& block : blocks) {
auto it = block.phis.begin();
while (it != block.phis.end()) {
// first case: all sources are the same as the destination.
// note - this will remove all phis with 1 or 0 arguments.
bool remove = true;
auto& dst = it->second.dest;
for (auto& src : it->second.sources) {
if (!map.same(src, dst)) {
remove = false;
break;
}
}
if (!remove) {
// second case. V_i = phi(combo of i, j)
remove = true;
auto v_i = it->second.dest;
std::optional<VarSSA> v_j;
for (auto& src : it->second.sources) {
if (!map.same(v_i, src)) {
// three cases:
if (!v_j.has_value()) {
// this is the first time we see j
v_j = src;
} else {
// we know j...
if (!map.same(*v_j, src)) {
// but it's not a match. three different vars, so give up.
remove = false;
break;
}
// else, we know j and matched it, continue checking
}
}
}
if (remove) {
ASSERT(v_j.has_value());
map.merge(*v_j, v_i);
}
}
if (remove) {
changed = true;
it = block.phis.erase(it);
} else {
it++;
}
}
}
return changed;
}
/*!
* Convert from SSA to a form without phis. This takes advantage of the following properties:
* - All phis have all sources and dest in the same HW register.
* - Merging variables in the same register is safe because they can't have overlapping use.
* - As a bonus, this never merges variables that we _know_ are distinct GOAL variables.
*/
void SSA::merge_all_phis() {
for (auto& block : blocks) {
for (auto& phi : block.phis) {
for (auto& src : phi.second.sources) {
map.merge_to_first(phi.second.dest, src);
}
}
block.phis.clear();
}
}
/*!
* Remaps all SSA variable ids to final variable IDs.
* This forces you to have all positive, consecutive IDs, with 0 being the entry value.
*/
void SSA::remap(int) {
// this keeps the order of variable assignments in the instruction order, not var_id order.
struct VarIdRecord {
std::unordered_set<int> set;
std::vector<int> order;
void insert(int x) {
if (set.find(x) == set.end()) {
set.insert(x);
order.push_back(x);
}
}
};
std::unordered_map<Register, VarIdRecord, Register::hash> used_vars;
// we do this in two passes. the first pass collects only the B0 variables and adds those first,
// so these remain index 0 (expected by later decompiler passes)
for (auto& block : blocks) {
ASSERT(block.phis.empty());
for (auto& instr : block.ins) {
if (instr.dst.has_value() && map.var_id(*instr.dst) == 0) {
used_vars[instr.dst->reg()].insert(map.var_id(*instr.dst));
}
for (auto& src : instr.src) {
if (map.var_id(src) == 0) {
used_vars[src.reg()].insert(map.var_id(src));
}
}
}
}
// and the second pass grabs all of them
for (auto& block : blocks) {
ASSERT(block.phis.empty());
for (auto& instr : block.ins) {
if (instr.dst.has_value()) {
used_vars[instr.dst->reg()].insert(map.var_id(*instr.dst));
}
for (auto& src : instr.src) {
used_vars[src.reg()].insert(map.var_id(src));
}
}
}
for (auto& reg_vars : used_vars) {
std::unordered_map<int, int> var_remap;
int i = 0;
for (auto var_id : reg_vars.second.order) {
var_remap[var_id] = i++;
}
// paranoid
ASSERT(var_remap.size() == reg_vars.second.order.size());
std::unordered_set<int> check;
for (auto kv : var_remap) {
check.insert(kv.second);
}
ASSERT(check.size() == var_remap.size());
map.remap_reg(reg_vars.first, var_remap);
program_read_vars[reg_vars.first].resize(i);
program_write_vars[reg_vars.first].resize(i);
}
}
namespace {
TP_Type lca_for_var_types(const TP_Type& existing,
const TP_Type& add,
const DecompilerTypeSystem& dts) {
bool changed;
auto normal = dts.tp_lca(existing, add, &changed);
return normal;
}
void update_var_info(VariableNames::VarInfo* info,
Register reg,
const TypeState& ts,
int var_id,
const DecompilerTypeSystem& dts) {
auto& type = ts.get(reg);
if (info->initialized) {
ASSERT(info->reg_id.id == var_id);
ASSERT(info->reg_id.reg == reg);
info->type = lca_for_var_types(info->type, type, dts);
} else {
info->reg_id.id = var_id;
info->reg_id.reg = reg;
info->type = type;
info->initialized = true;
}
}
bool merge_infos(VariableNames::VarInfo* info1,
VariableNames::VarInfo* info2,
const DecompilerTypeSystem& dts) {
if (info1->initialized && info2->initialized) {
auto new_type = lca_for_var_types(info1->type, info2->type, dts);
info1->type = new_type;
info2->type = new_type;
return true;
}
return false;
}
void merge_infos(
std::unordered_map<Register, std::vector<VariableNames::VarInfo>, Register::hash>& info1,
std::unordered_map<Register, std::vector<VariableNames::VarInfo>, Register::hash>& info2,
const DecompilerTypeSystem& dts) {
for (auto& [reg, infos] : info1) {
auto other = info2.find(reg);
if (other != info2.end()) {
for (size_t i = 0; i < std::min(other->second.size(), infos.size()); i++) {
merge_infos(&infos.at(i), &other->second.at(i), dts);
}
}
}
}
} // namespace
/*!
* Create variable info for each variable.
* Note: the "event_handler_hack" is supposed to help with the use of "none" typed variables
* that are actually used. It's a hack because we don't really have enough information to know if
* the none variables
*/
void SSA::make_vars(const Function& function, const DecompilerTypeSystem& dts) {
for (int block_id = 0; block_id < int(blocks.size()); block_id++) {
const auto& block = blocks.at(block_id);
const TypeState* init_types = &function.ir2.env.get_types_at_block_entry(block_id);
for (auto& instr : block.ins) {
auto op_id = instr.op_id;
if (op_id < 0) {
continue;
}
const TypeState* end_types = &function.ir2.env.get_types_after_op(op_id);
if (instr.dst.has_value()) {
auto var_id = map.var_id(*instr.dst);
auto* info = &program_write_vars[instr.dst->reg()].at(var_id);
update_var_info(info, instr.dst->reg(), *end_types, var_id, dts);
}
for (auto& src : instr.src) {
auto var_id = map.var_id(src);
auto* info = &program_read_vars[src.reg()].at(var_id);
update_var_info(info, src.reg(), *init_types, var_id, dts);
}
init_types = end_types;
}
}
// override the types of the variables for function arguments:
ASSERT(function.type.arg_count() > 0);
for (int arg_idx = 0; arg_idx < int(function.type.arg_count()) - 1; arg_idx++) {
auto arg_reg = Register::get_arg_reg(arg_idx);
if (!program_read_vars[arg_reg].empty()) {
program_read_vars[arg_reg].at(0).type = TP_Type::make_from_ts(function.type.get_arg(arg_idx));
}
if (!program_write_vars[arg_reg].empty()) {
program_write_vars[arg_reg].at(0).type =
TP_Type::make_from_ts(function.type.get_arg(arg_idx));
}
}
merge_infos(program_write_vars, program_read_vars, dts);
// copy types from input argument coloring moves:
for (auto& instr : blocks.at(0).ins) {
if (instr.is_arg_coloring_move) {
auto src_ssa = instr.src.at(0);
for (int arg_idx = 0; arg_idx < int(function.type.arg_count()) - 1; arg_idx++) {
if (Register::get_arg_reg(arg_idx) == src_ssa.reg()) {
// copy the type from here.
auto dst = instr.dst;
ASSERT(dst);
auto dst_reg = instr.dst->reg();
auto dst_varid = map.var_id(*dst);
if ((int)program_read_vars[dst_reg].size() > dst_varid) {
program_read_vars[dst_reg].at(dst_varid).type =
TP_Type::make_from_ts(function.type.get_arg(arg_idx));
}
if ((int)program_write_vars[dst_reg].size() > dst_varid) {
program_write_vars[dst_reg].at(dst_varid).type =
TP_Type::make_from_ts(function.type.get_arg(arg_idx));
}
}
}
}
}
}
void remap_color_move(
std::unordered_map<Register, std::vector<VariableNames::VarInfo>, Register::hash>& mapping,
const RegId& old_var,
const RegId& new_var) {
auto old_kv = mapping.find(old_var.reg);
if (old_kv == mapping.end()) {
return;
}
if (int(old_kv->second.size()) <= old_var.id) {
return;
}
old_kv->second.at(old_var.id).reg_id = new_var;
}
VariableNames SSA::get_vars() const {
VariableNames result;
result.read_vars = program_read_vars;
result.write_vars = program_write_vars;
for (int block_id = 0; block_id < int(blocks.size()); block_id++) {
const auto& block = blocks.at(block_id);
for (auto& instr : block.ins) {
auto op_id = instr.op_id;
if (op_id < 0) {
continue;
}
if (instr.dst.has_value()) {
auto& ids = result.write_opid_to_varid[instr.dst->reg()];
if (int(ids.size()) <= op_id) {
ids.resize(op_id + 1);
}
ids.at(op_id) = map.var_id(*instr.dst);
}
}
}
for (int block_id = 0; block_id < int(blocks.size()); block_id++) {
const auto& block = blocks.at(block_id);
for (auto& instr : block.ins) {
auto op_id = instr.op_id;
if (op_id < 0) {
continue;
}
for (auto& src : instr.src) {
auto& ids = result.read_opid_to_varid[src.reg()];
if (int(ids.size()) <= op_id) {
ids.resize(op_id + 1);
}
ids.at(op_id) = map.var_id(src);
}
}
}
for (auto& instr : blocks.at(0).ins) {
if (instr.is_arg_coloring_move) {
result.eliminated_move_op_ids.insert(instr.op_id);
ASSERT(instr.dst.has_value());
ASSERT(instr.src.size() == 1);
RegId new_regid, old_regid;
new_regid.reg = instr.src.at(0).reg();
new_regid.id = map.var_id(instr.src.at(0));
old_regid.reg = instr.dst->reg();
old_regid.id = map.var_id(*instr.dst);
remap_color_move(result.read_vars, old_regid, new_regid);
remap_color_move(result.write_vars, old_regid, new_regid);
}
}
return result;
}
/*!
* Get a map from access to SSA variable.
*/
RegAccessMap<int> SSA::get_ssa_mapping() {
RegAccessMap<int> result;
for (const auto& block : blocks) {
for (const auto& instr : block.ins) {
if (instr.dst.has_value()) {
RegisterAccess access(AccessMode::WRITE, instr.dst->reg(), instr.op_id, true);
result[access] = map.var_id(*instr.dst);
}
for (const auto& src : instr.src) {
RegisterAccess access(AccessMode::READ, src.reg(), instr.op_id, true);
result[access] = map.var_id(src);
}
}
}
return result;
}
/*!
* Find Program Variables that can safely be propagated.
*/
std::unordered_map<RegId, UseDefInfo, RegId::hash> SSA::get_use_def_info(
const RegAccessMap<int>& ssa_info) const {
std::unordered_map<RegId, UseDefInfo, RegId::hash> result;
// now, iterate through instruction
// for (const auto& block : blocks) {
for (size_t block_id = 0; block_id < blocks.size(); block_id++) {
const auto& block = blocks[block_id];
for (const auto& instr : block.ins) {
if (instr.is_dead_set) {
continue;
}
if (instr.dst.has_value()) {
// get the SSA var:
auto ssa_var_id =
ssa_info.at(RegisterAccess(AccessMode::WRITE, instr.dst->reg(), instr.op_id, true));
// get the info
auto& info = result[RegId(instr.dst->reg(), map.var_id(*instr.dst))];
// remember which SSA variable was in use here
info.defs.push_back({instr.op_id, (int)block_id, AccessMode::WRITE});
info.ssa_vars.insert(ssa_var_id);
}
for (const auto& src : instr.src) {
// get the SSA var:
auto ssa_var_id =
ssa_info.at(RegisterAccess(AccessMode::READ, src.reg(), instr.op_id, true));
// get the info
auto& info = result[RegId(src.reg(), map.var_id(src))];
// remember the variable
info.ssa_vars.insert(ssa_var_id);
info.uses.push_back({instr.op_id, (int)block_id, AccessMode::READ});
}
}
}
return result;
}
namespace {
VariableNames::VarInfo* try_lookup_read(VariableNames* in, RegId var_id) {
auto kv = in->read_vars.find(var_id.reg);
if (kv != in->read_vars.end()) {
if ((int)kv->second.size() > var_id.id) {
auto& entry = kv->second.at(var_id.id);
if (entry.initialized) {
return &entry;
}
}
}
return nullptr;
}
VariableNames::VarInfo* try_lookup_write(VariableNames* in, RegId var_id) {
auto kv = in->write_vars.find(var_id.reg);
if (kv != in->write_vars.end()) {
if ((int)kv->second.size() > var_id.id) {
auto& entry = kv->second.at(var_id.id);
if (entry.initialized) {
return &entry;
}
}
}
return nullptr;
}
bool is_128bit(const TP_Type& type, const DecompilerTypeSystem& dts) {
if (dts.ts.tc(TypeSpec("uint128"), type.typespec())) {
return true;
}
if (dts.ts.tc(TypeSpec("int128"), type.typespec())) {
return true;
}
if (type.kind == TP_Type::Kind::PCPYUD_BITFIELD) {
return true;
}
if (type.kind == TP_Type::Kind::PCPYUD_BITFIELD_AND) {
return true;
}
return false;
}
void promote_register_class(const Function& func,
VariableNames* result,
const DecompilerTypeSystem& dts) {
enum class PromotionType { PROMOTE_64, PROMOTE_128 };
std::unordered_map<RegId, PromotionType, RegId::hash> promote_map;
// here we loop through ops and find cases where we need to adjust types.
auto& ao = func.ir2.atomic_ops;
for (size_t op_idx = 0; op_idx < ao->ops.size() - 1; op_idx++) {
auto* op = ao->ops.at(op_idx).get();
auto op_as_asm = dynamic_cast<AsmOp*>(op);
if (op_as_asm) {
auto& instr = op_as_asm->instruction();
if (gOpcodeInfo[(int)instr.kind].gpr_128) {
for (auto& reg : op_as_asm->write_regs()) {
if (reg.get_kind() == Reg::GPR) {
auto& info = result->lookup(reg, op_idx, AccessMode::WRITE);
promote_map[info.reg_id] = PromotionType::PROMOTE_128;
}
}
for (auto& reg : op_as_asm->read_regs()) {
if (reg.get_kind() == Reg::GPR) {
auto& info = result->lookup(reg, op_idx, AccessMode::READ);
promote_map[info.reg_id] = PromotionType::PROMOTE_128;
}
}
}
}
}
for (const auto& promotion : promote_map) {
// lg::print("Promote {} to {}\n", promotion.first.print(), "uint128");
// first reads:
auto read_info = try_lookup_read(result, promotion.first);
auto write_info = try_lookup_write(result, promotion.first);
ASSERT(read_info || write_info);
if (read_info && !is_128bit(read_info->type, dts)) {
read_info->type = TP_Type::make_from_ts("uint128");
}
if (write_info && !is_128bit(write_info->type, dts)) {
write_info->type = TP_Type::make_from_ts("uint128");
}
}
}
} // namespace
std::optional<VariableNames> run_variable_renaming(const Function& function,
const RegUsageInfo& rui,
const FunctionAtomicOps& ops,
const DecompilerTypeSystem& dts,
bool debug_prints) {
if (debug_prints) {
std::string debug_in;
for (int block_id = 0; block_id < rui.block_count(); block_id++) {
auto& block_info = rui.block.at(block_id);
// const auto& block = function.basic_blocks.at(block_id);
int start_op = ops.block_id_to_first_atomic_op.at(block_id);
int end_op = ops.block_id_to_end_atomic_op.at(block_id);
debug_in += fmt::format("Block {}\n", block_id);
debug_in += fmt::format(" use: {}\n", reg_to_string(block_info.use));
debug_in += fmt::format(" in : {}\n", reg_to_string(block_info.input));
debug_in += "pred: ";
for (auto p : function.basic_blocks.at(block_id).pred) {
debug_in += std::to_string(p);
debug_in += ' ';
}
debug_in += '\n';
for (int op_id = start_op; op_id < end_op; op_id++) {
debug_in +=
fmt::format(" [{:03d}] {} : ", op_id, ops.ops.at(op_id)->to_string(function.ir2.env));
auto& op_info = rui.op.at(op_id);
for (auto reg : op_info.live) {
debug_in += reg.to_charp();
debug_in += ' ';
}
debug_in += '\n';
}
debug_in += fmt::format(" def: {}\n", reg_to_string(block_info.defs));
debug_in += fmt::format(" out: {}\n\n", reg_to_string(block_info.output));
}
lg::print("Debug Input\n{}\n----------------------------------\n", debug_in);
}
// Create and convert to SSA
auto ssa = make_rc_ssa(function, rui, ops);
if (debug_prints) {
lg::print("Basic SSA\n{}\n------------------------------------\n", ssa.print());
}
// eliminate PHIs that are not needed, still keeping us in SSA.
while (ssa.simplify()) {
}
if (debug_prints) {
lg::print("Simplified SSA\n{}-------------------------------\n", ssa.print());
}
// merge special registers
ssa.merge_reg_to_single_variable(Register(Reg::GPR, Reg::SP));
ssa.merge_reg_to_single_variable(Register(Reg::GPR, Reg::S6));
// remember what the SSA mapping was:
auto ssa_mapping = ssa.get_ssa_mapping();
// Merge phis to return to executable code and exit SSA.
if (debug_prints) {
ssa.map.debug_print_map();
}
ssa.merge_all_phis();
if (debug_prints) {
lg::print("{}", ssa.print());
}
if (debug_prints) {
ssa.map.debug_print_map();
}
// merge same vars (decided this made things worse)
// do rename
ssa.remap(arg_count(function));
if (debug_prints) {
lg::print("{}", ssa.print());
}
if (function.ir2.env.has_type_analysis()) {
// make vars
ssa.make_vars(function, dts);
//
auto result = ssa.get_vars();
result.use_def_info = ssa.get_use_def_info(ssa_mapping);
promote_register_class(function, &result, dts);
return result;
} else {
return std::nullopt;
}
}
} // namespace decompiler