1 files changed, 251 insertions, 0 deletions
diff --git a/src/input/gc/RelModule.cpp b/src/input/gc/RelModule.cpp
new file mode 100644
index 0000000..de263af
--- /dev/null
+++ b/src/input/gc/RelModule.cpp
@@ -0,0 +1,251 @@
+#include "RelModule.h"
+#include "BlockReader.h"
+
+#include <cstdlib>
+#include <cstring>
+#include <stdexcept>
+
+extern "C" {
+#include <libyaz0/yaz0.h>
+}
+
+namespace GC {
+
+static constexpr uint32_t REL_HEADER_V1_SIZE = 0x40;
+
+RelModule::RelModule(std::vector<uint8_t> data) : mData(std::move(data)) {
+    if (mData.size() < REL_HEADER_V1_SIZE) {
+        throw std::runtime_error("REL: file too small");
+    }
+    const uint8_t* h = mData.data();
+    mId = ReadBE32(h + 0x00);
+    const uint32_t numSections = ReadBE32(h + 0x0C);
+    const uint32_t sectionInfoOffset = ReadBE32(h + 0x10);
+    mVersion = ReadBE32(h + 0x1C);
+    mBssSize = ReadBE32(h + 0x20);
+    mRelOffset = ReadBE32(h + 0x24);
+    mImpOffset = ReadBE32(h + 0x28);
+    mImpSize = ReadBE32(h + 0x2C);
+
+    if (static_cast<uint64_t>(sectionInfoOffset) + numSections * 8ULL > mData.size()) {
+        throw std::runtime_error("REL: section table out of range");
+    }
+    for (uint32_t i = 0; i < numSections; i++) {
+        const uint8_t* s = h + sectionInfoOffset + i * 8;
+        const uint32_t raw = ReadBE32(s);
+        RelSectionInfo info = { raw & ~1u, ReadBE32(s + 4), (raw & 1) != 0 };
+        if (info.offset != 0 && static_cast<uint64_t>(info.offset) + info.size > mData.size()) {
+            throw std::runtime_error("REL: section " + std::to_string(i) + " out of range");
+        }
+        mSections.push_back(info);
+    }
+
+    if (static_cast<uint64_t>(mImpOffset) + mImpSize > mData.size()) {
+        throw std::runtime_error("REL: import table out of range");
+    }
+    for (uint32_t off = 0; off + 8 <= mImpSize; off += 8) {
+        mImports.push_back({ ReadBE32(h + mImpOffset + off), ReadBE32(h + mImpOffset + off + 4) });
+    }
+}
+
+std::vector<uint8_t> RelModule::Decompress(const std::vector<uint8_t>& data) {
+    if (data.size() < 16 || std::memcmp(data.data(), "Yaz0", 4) != 0) {
+        return data;
+    }
+    uint32_t size = 0;
+    uint8_t* decoded = yaz0_decode(data.data(), &size);
+    if (decoded == nullptr) {
+        throw std::runtime_error("Failed to decode Yaz0");
+    }
+    std::vector<uint8_t> out(decoded, decoded + size);
+    free(decoded);
+    return out;
+}
+
+std::vector<RelRelocation> RelModule::GetRelocations(const RelImport& imp) const {
+    std::vector<RelRelocation> out;
+    for (uint64_t off = imp.offset; off + 8 <= mData.size(); off += 8) {
+        const uint8_t* r = mData.data() + off;
+        RelRelocation rel = { ReadBE16(r), r[2], r[3], ReadBE32(r + 4) };
+        out.push_back(rel);
+        if (rel.type == R_DOLPHIN_END) {
+            return out;
+        }
+    }
+    throw std::runtime_error("REL: relocation list without R_DOLPHIN_END");
+}
+
+std::vector<std::string> RelModule::GetSectionNames() const {
+    static const char* standard[] = { "", ".text", ".ctors", ".dtors", ".rodata", ".data", ".bss" };
+    std::vector<std::string> names(mSections.size());
+
+    const bool isStandard = mSections.size() == 7 && mSections[1].exec && !mSections[6].exec &&
+                            (mSections[6].IsBss() || mSections[6].size == 0);
+    if (isStandard) {
+        for (size_t i = 0; i < names.size(); i++) {
+            names[i] = standard[i];
+        }
+        return names;
+    }
+
+    std::vector<size_t> data;
+    int texts = 0;
+    for (size_t i = 0; i < mSections.size(); i++) {
+        const auto& s = mSections[i];
+        if (s.offset == 0 && s.size == 0) {
+            continue;
+        }
+        if (s.IsBss()) {
+            names[i] = ".bss";
+        } else if (s.exec) {
+            names[i] = texts++ == 0 ? ".text" : ".text" + std::to_string(texts - 1);
+        } else {
+            data.push_back(i);
+        }
+    }
+    static const char* dataNames[] = { ".ctors", ".dtors", ".rodata", ".data" };
+    for (size_t j = 0; j < data.size(); j++) {
+        names[data[j]] = data.size() == 4 ? dataNames[j] : ".data" + std::to_string(j);
+    }
+    return names;
+}
+
+std::optional<uint32_t> RelModule::FindSection(const std::string& name) const {
+    const auto names = GetSectionNames();
+    for (size_t i = 0; i < names.size(); i++) {
+        if (names[i] == name) {
+            return static_cast<uint32_t>(i);
+        }
+    }
+    char* end = nullptr;
+    const unsigned long index = std::strtoul(name.c_str(), &end, 0);
+    if (!name.empty() && end != nullptr && *end == '\0' && index < mSections.size()) {
+        return static_cast<uint32_t>(index);
+    }
+    return std::nullopt;
+}
+
+std::vector<std::vector<uint8_t>> RelModule::GetSectionData() const {
+    std::vector<std::vector<uint8_t>> out;
+    for (const auto& s : mSections) {
+        if (s.offset == 0) {
+            out.emplace_back(s.size, 0);
+        } else {
+            out.emplace_back(mData.begin() + s.offset, mData.begin() + s.offset + s.size);
+        }
+    }
+    return out;
+}
+
+RelLinkStats RelModule::Link(const std::vector<std::optional<uint32_t>>& bases,
+                             std::vector<std::vector<uint8_t>>& sections) const {
+    RelLinkStats stats;
+
+    for (const auto& imp : this->mImports) {
+        const bool self = imp.moduleId == this->mId;
+        if (!self && imp.moduleId != 0) {
+            for (const auto& rel : GetRelocations(imp)) {
+                if (rel.type < R_DOLPHIN_NOP) {
+                    stats.unknownModule++;
+                }
+            }
+            continue;
+        }
+
+        std::optional<uint32_t> section;
+        uint32_t cursor = 0;
+
+        for (const auto& rel : GetRelocations(imp)) {
+            cursor += rel.offset;
+
+            if (rel.type == R_DOLPHIN_END) {
+                break;
+            }
+            if (rel.type == R_DOLPHIN_NOP) {
+                continue;
+            }
+            if (rel.type == R_DOLPHIN_SECTION) {
+                section = rel.section;
+                cursor = 0;
+                continue;
+            }
+            if (rel.type == R_PPC_NONE) {
+                continue;
+            }
+
+            if (!section.has_value() || section.value() >= sections.size() || section.value() >= bases.size() ||
+                !bases[section.value()].has_value()) {
+                stats.skippedUnplaced++;
+                continue;
+            }
+
+            uint32_t offset = 0;
+            if (self) {
+                if (rel.section >= bases.size() || !bases[rel.section].has_value()) {
+                    stats.unresolvedTarget++;
+                    stats.unresolved.push_back({ section.value(), cursor, rel.type, rel.section, rel.addend });
+                    continue;
+                }
+                offset = bases[rel.section].value();
+            }
+
+            auto& data = sections[section.value()];
+            const uint32_t width = rel.type == R_PPC_ADDR32 || rel.type == R_PPC_ADDR24 ||
+                                           rel.type == R_PPC_REL24 || rel.type == R_PPC_ADDR14 ||
+                                           rel.type == R_PPC_ADDR14_BRTAKEN || rel.type == R_PPC_ADDR14_BRNTAKEN ||
+                                           rel.type == R_PPC_REL14 || rel.type == R_PPC_REL14_BRTAKEN ||
+                                           rel.type == R_PPC_REL14_BRNTAKEN
+                                       ? 4
+                                       : 2;
+            if (static_cast<uint64_t>(cursor) + width > data.size()) {
+                throw std::runtime_error("REL: relocation writes past the end of section " +
+                                         std::to_string(section.value()));
+            }
+
+            uint8_t* p = data.data() + cursor;
+            const uint32_t where = bases[section.value()].value() + cursor;
+            const uint32_t x = offset + rel.addend;
+
+            switch (rel.type) {
+                case R_PPC_ADDR32:
+                    WriteBE32(p, x);
+                    break;
+                case R_PPC_ADDR24:
+                    WriteBE32(p, (ReadBE32(p) & ~0x03FFFFFCu) | (x & 0x03FFFFFCu));
+                    break;
+                case R_PPC_ADDR16:
+                case R_PPC_ADDR16_LO:
+                    WriteBE16(p, x & 0xFFFF);
+                    break;
+                case R_PPC_ADDR16_HI:
+                    WriteBE16(p, (x >> 16) & 0xFFFF);
+                    break;
+                case R_PPC_ADDR16_HA:
+                    WriteBE16(p, ((x >> 16) + ((x & 0x8000) ? 1 : 0)) & 0xFFFF);
+                    break;
+                case R_PPC_REL24:
+                    WriteBE32(p, (ReadBE32(p) & ~0x03FFFFFCu) | ((x - where) & 0x03FFFFFCu));
+                    break;
+                case R_PPC_ADDR14:
+                case R_PPC_ADDR14_BRTAKEN:
+                case R_PPC_ADDR14_BRNTAKEN:
+                    WriteBE32(p, (ReadBE32(p) & ~0xFFFCu) | (x & 0xFFFCu));
+                    break;
+                case R_PPC_REL14:
+                case R_PPC_REL14_BRTAKEN:
+                case R_PPC_REL14_BRNTAKEN:
+                    WriteBE32(p, (ReadBE32(p) & ~0xFFFCu) | ((x - where) & 0xFFFCu));
+                    break;
+                default:
+                    stats.unknownType++;
+                    continue;
+            }
+            stats.applied++;
+            stats.byType[rel.type]++;
+        }
+    }
+
+    return stats;
+}
+
+} // namespace GC