psxrecomp/recompiler/tests/reachable_discovery_test.cpp

#include "function_analysis.h"
#include "ps1_exe_parser.h"

#include <cstdint>
#include <cstdio>
#include <cstring>
#include <set>
#include <string>
#include <vector>

namespace {

constexpr uint32_t kLoad = 0x80010000u;
int failures = 0;

#define CHECK(cond, message) do {                                              \
    if (!(cond)) {                                                             \
        std::fprintf(stderr, "FAIL: %s\n", (message));                        \
        failures++;                                                            \
    }                                                                          \
} while (0)

void put32(std::vector<uint8_t>& data, size_t offset, uint32_t value) {
    data[offset + 0] = static_cast<uint8_t>(value);
    data[offset + 1] = static_cast<uint8_t>(value >> 8);
    data[offset + 2] = static_cast<uint8_t>(value >> 16);
    data[offset + 3] = static_cast<uint8_t>(value >> 24);
}

uint32_t jal(uint32_t target) {
    return 0x0C000000u | ((target >> 2) & 0x03FFFFFFu);
}

std::vector<uint8_t> make_exe_buffer(uint32_t image_size,
                                     uint32_t entry = kLoad) {
    std::vector<uint8_t> data(2048u + image_size, 0);
    std::memcpy(data.data(), "PS-X EXE", 8);
    put32(data, 0x10, entry);
    put32(data, 0x18, kLoad);
    put32(data, 0x1C, image_size);
    return data;
}

PSXRecomp::PS1Executable parse(std::vector<uint8_t> data) {
    std::string error;
    auto exe = PSXRecomp::PS1ExeParser::parse_buffer(data, error);
    CHECK(exe.has_value(), error.c_str());
    return exe.value();
}

std::set<uint32_t> starts(const PSXRecomp::FunctionAnalysisResult& result) {
    std::set<uint32_t> out;
    for (const auto& function : result.functions) out.insert(function.start_addr);
    return out;
}

} // namespace

int main() {
    auto image = make_exe_buffer(0x2000);
    const size_t text = 2048;

    // Root: direct call to a callable target, unresolved jalr, direct call
    // beyond the eventual bound, then return.
    put32(image, text + 0x00, jal(kLoad + 0x100));
    put32(image, text + 0x04, 0x00000000u);
    put32(image, text + 0x08, 0x0320F809u); // jalr $ra,$t9 (unresolved)
    put32(image, text + 0x0C, 0x00000000u);
    put32(image, text + 0x10, jal(kLoad + 0x1100));
    put32(image, text + 0x14, 0x00000000u);
    put32(image, text + 0x18, 0x03E00008u);
    put32(image, text + 0x1C, 0x00000000u);

    // Callable direct target.
    put32(image, text + 0x100, 0x27BDFFF0u);
    put32(image, text + 0x104, 0x03E00008u);
    put32(image, text + 0x108, 0x27BD0010u);

    // Valid-looking callback not referenced by a direct call.
    put32(image, text + 0x200, 0x27BDFFF0u);
    put32(image, text + 0x204, 0x03E00008u);
    put32(image, text + 0x208, 0x27BD0010u);

    // Callable target outside the verified static bound.
    put32(image, text + 0x1100, 0x27BDFFF0u);
    put32(image, text + 0x1104, 0x03E00008u);
    put32(image, text + 0x1108, 0x27BD0010u);

    auto exe = parse(image);
    std::string error;
    CHECK(PSXRecomp::apply_static_analysis_bound(exe, 0x1000, error),
          "valid page-aligned analysis bound is accepted");
    CHECK(exe.code_size() == 0x1000 && exe.code_data.size() == 0x1000,
          "accepted bound truncates header and analysis payload together");

    PSXRecomp::FunctionAnalyzer analyzer(exe);
    const auto reachable = starts(analyzer.analyze_exact_entries({kLoad}));
    CHECK(reachable == std::set<uint32_t>({kLoad, kLoad + 0x100}),
          "reachable analysis follows direct callable JAL only");
    CHECK(!reachable.count(kLoad + 0x200),
          "unseen indirect callback fails closed");
    CHECK(!reachable.count(kLoad + 0x1100),
          "direct target beyond verified bound fails closed");

    PSXRecomp::FunctionAnalyzer seeded_analyzer(exe);
    const auto seeded = starts(
        seeded_analyzer.analyze_exact_entries({kLoad, kLoad + 0x200}));
    CHECK(seeded.count(kLoad + 0x200),
          "evidence-backed explicit callback seed is compiled");

    auto bad = parse(image);
    const auto original_size = bad.code_data.size();
    CHECK(!PSXRecomp::apply_static_analysis_bound(bad, 0x1800, error),
          "non-page-aligned truncation is rejected");
    CHECK(bad.code_size() == 0x2000 && bad.code_data.size() == original_size,
          "invalid bound leaves parsed image unchanged");
    CHECK(!PSXRecomp::apply_static_analysis_bound(bad, 0x3000, error),
          "oversized noncanonical bound is rejected");
    CHECK(!PSXRecomp::apply_static_analysis_bound(bad, 0, error),
          "zero bound is rejected");

    auto excludes_entry = parse(image);
    excludes_entry.header.initial_pc = kLoad + 0x1000;
    CHECK(!PSXRecomp::apply_static_analysis_bound(excludes_entry, 0x1000, error),
          "bound excluding entry point is rejected");

    auto rounded = parse(make_exe_buffer(0x1800));
    CHECK(PSXRecomp::apply_static_analysis_bound(rounded, 0x2000, error),
          "canonical generated final-page reservation remains compatible");
    CHECK(rounded.code_size() == 0x1800,
          "page reservation does not widen static analysis payload");

    if (failures) {
        std::fprintf(stderr, "FAILED (%d)\n", failures);
        return 1;
    }
    std::puts("ALL PASS");
    return 0;
}