[dynarmic] Remove redundant constant pool ops

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/core/file_sys/fs_path.h

@@ -1,6 +1,3 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
 // SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -146,16 +143,20 @@ public:
         return m_str;
     }
 
-    size_t GetLength() const {
-        return std::strlen(this->GetString());
+    constexpr size_t GetLength() const {
+        if (std::is_constant_evaluated()) {
+            return Strlen(this->GetString());
+        } else {
+            return std::strlen(this->GetString());
+        }
     }
 
     constexpr bool IsEmpty() const {
         return *m_str == '\x00';
     }
 
-    bool IsMatchHead(const char* p, size_t len) const {
-        return std::strncmp(this->GetString(), p, len) == 0;
+    constexpr bool IsMatchHead(const char* p, size_t len) const {
+        return Strncmp(this->GetString(), p, len) == 0;
     }
 
     Result Initialize(const Path& rhs) {
@@ -168,7 +169,7 @@ public:
         R_TRY(this->Preallocate(len + 1));
 
         // Copy the path
-        const size_t copied = strlcpy(m_write_buffer.Get(), rhs.GetString(), len + 1);
+        const size_t copied = Strlcpy<char>(m_write_buffer.Get(), rhs.GetString(), len + 1);
         R_UNLESS(copied == len, ResultUnexpectedInPathA);
 
         // Set normalized
@@ -330,14 +331,14 @@ public:
         // Get our write buffer
         auto* dst = m_write_buffer.Get();
         if (old_write_buffer.Get() != nullptr && cur_len > 0) {
-            strlcpy(dst, old_write_buffer.Get(), cur_len + 1);
+            Strlcpy<char>(dst, old_write_buffer.Get(), cur_len + 1);
         }
 
         // Add separator
         dst[cur_len] = '/';
 
         // Copy the child path
-        const size_t copied = strlcpy(dst + cur_len + 1, c, child_len + 1);
+        const size_t copied = Strlcpy<char>(dst + cur_len + 1, c, child_len + 1);
         R_UNLESS(copied == child_len, ResultUnexpectedInPathA);
 
         R_SUCCEED();
@@ -374,7 +375,7 @@ public:
         if (m_write_buffer.Get() == nullptr) {
             if (const auto len = std::strlen(m_str); len > 0) {
                 R_TRY(this->Preallocate(len));
-                strlcpy(m_write_buffer.Get(), m_str, len + 1);
+                Strlcpy<char>(m_write_buffer.Get(), m_str, len + 1);
             }
         }
 
@@ -496,7 +497,7 @@ private:
             R_TRY(this->Preallocate(size + 1));
 
             // Copy the path
-            const size_t copied = strlcpy(m_write_buffer.Get(), path, size + 1);
+            const size_t copied = Strlcpy<char>(m_write_buffer.Get(), path, size + 1);
             R_UNLESS(copied >= size, ResultUnexpectedInPathA);
         } else {
             // We can just clear the buffer

src/core/file_sys/fs_path_utility.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 // SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
@@ -1217,7 +1217,7 @@ public:
                 replaced_src = static_cast<char*>(Allocate(replaced_src_len));
             }
 
-            strlcpy(replaced_src, src, replaced_src_len);
+            Strlcpy<char>(replaced_src, src, replaced_src_len);
 
             Replace(replaced_src, replaced_src_len, AlternateDirectorySeparator,
                     DirectorySeparator);

src/core/file_sys/fs_string_util.h

@@ -1,6 +1,3 @@
-// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
-// SPDX-License-Identifier: GPL-3.0-or-later
-
 // SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -10,6 +7,85 @@
 
 namespace FileSys {
 
+template <typename T>
+constexpr int Strlen(const T* str) {
+    ASSERT(str != nullptr);
+
+    int length = 0;
+    while (*str++) {
+        ++length;
+    }
+
+    return length;
+}
+
+template <typename T>
+constexpr int Strnlen(const T* str, std::size_t count) {
+    return Strnlen(str, static_cast<int>(count));
+}
+
+template <typename T>
+constexpr int Strnlen(const T* str, int count) {
+    ASSERT(str != nullptr);
+    ASSERT(count >= 0);
+
+    int length = 0;
+    while (count-- && *str++) {
+        ++length;
+    }
+
+    return length;
+}
+
+template <typename T>
+constexpr int Strncmp(const T* lhs, const T* rhs, std::size_t count) {
+    return Strncmp(lhs, rhs, static_cast<int>(count));
+}
+
+template <typename T>
+constexpr int Strncmp(const T* lhs, const T* rhs, int count) {
+    ASSERT(lhs != nullptr);
+    ASSERT(rhs != nullptr);
+    ASSERT(count >= 0);
+
+    if (count == 0) {
+        return 0;
+    }
+
+    T l, r;
+    do {
+        l = *(lhs++);
+        r = *(rhs++);
+    } while (l && (l == r) && (--count));
+
+    return l - r;
+}
+
+template <typename T>
+static constexpr int Strlcpy(T* dst, const T* src, std::size_t count) {
+    return Strlcpy<T>(dst, src, static_cast<int>(count));
+}
+
+template <typename T>
+static constexpr int Strlcpy(T* dst, const T* src, int count) {
+    ASSERT(dst != nullptr);
+    ASSERT(src != nullptr);
+
+    const T* cur = src;
+    if (count > 0) {
+        while ((--count) && *cur) {
+            *(dst++) = *(cur++);
+        }
+        *dst = 0;
+    }
+
+    while (*cur) {
+        cur++;
+    }
+
+    return static_cast<int>(cur - src);
+}
+
 enum CharacterEncodingResult {
     CharacterEncodingResult_Success = 0,
     CharacterEncodingResult_InsufficientLength = 1,

src/dynarmic/src/dynarmic/backend/x64/constant_pool.cpp

@@ -7,34 +7,27 @@
  */
 
 #include <cstring>
-
-#include "common/assert.h"
-
+#include <cassert>
 #include "dynarmic/backend/x64/block_of_code.h"
 #include "dynarmic/backend/x64/constant_pool.h"
 
 namespace Dynarmic::Backend::X64 {
 
-ConstantPool::ConstantPool(BlockOfCode& code, size_t size)
-    : insertion_point(0)
-{
-    code.EnsureMemoryCommitted(align_size + size);
-    code.int3();
+ConstantPool::ConstantPool(BlockOfCode& code, size_t size) noexcept {
+    auto const align_size = 64; //always align to cacheline
+    code.EnsureMemoryCommitted(2 * align_size + size);
     code.align(align_size);
-    pool = std::span<ConstantT>(reinterpret_cast<ConstantT*>(code.AllocateFromCodeSpace(size)), size / align_size);
+    pool = std::span<u128>(static_cast<u128*>(code.AllocateFromCodeSpace(size)), size / sizeof(u128));
 }
 
-Xbyak::Address ConstantPool::GetConstant(BlockOfCode& code, const Xbyak::AddressFrame& frame, u64 lower, u64 upper) {
-    const auto constant = ConstantT(lower, upper);
-    auto it = constant_info.find(constant);
-    if (it == constant_info.end()) {
-        ASSERT(insertion_point < pool.size());
-        ConstantT& target_constant = pool[insertion_point];
-        target_constant = constant;
-        it = constant_info.insert({constant, &target_constant}).first;
-        ++insertion_point;
-    }
-    return frame[code.rip + it->second];
+Xbyak::Address ConstantPool::GetConstant(BlockOfCode& code, const Xbyak::AddressFrame& frame, u64 lo, u64 hi) noexcept {
+    // offset grows iff new constant is added
+    auto const key = std::make_pair(lo, hi);
+    auto const val = u32(constant_info.size());
+    auto const [it, _] = constant_info.insert({key, val});
+    // if it != constant_info.end(): assume(pool[it->second] == c);
+    pool[it->second] = u128{lo, hi};
+    return frame[code.rip + std::addressof(pool[it->second])];
 }
 
 }  // namespace Dynarmic::Backend::X64

src/dynarmic/src/dynarmic/backend/x64/constant_pool.h

@@ -12,6 +12,7 @@
 #include <cstddef>
 #include <span>
 #include <utility>
+#include <boost/functional/hash.hpp>
 
 #include "common/common_types.h"
 #include "common/container/unordered_map.h"
@@ -21,31 +22,17 @@ namespace Dynarmic::Backend::X64 {
 
 class BlockOfCode;
 
-/// ConstantPool allocates a block of memory from BlockOfCode.
+/// @brief ConstantPool allocates a block of memory from BlockOfCode.
 /// It places constants into this block of memory, returning the address
 /// of the memory location where the constant is placed. If the constant
 /// already exists, its memory location is reused.
 class ConstantPool final {
 public:
-    ConstantPool(BlockOfCode& code, size_t size);
-
-    Xbyak::Address GetConstant(BlockOfCode& code, const Xbyak::AddressFrame& frame, u64 lower, u64 upper = 0);
-
-private:
-    static constexpr size_t align_size = 16;  // bytes
-
-    using ConstantT = std::pair<u64, u64>;
-    static_assert(sizeof(ConstantT) == align_size);
-
-    struct ConstantHash {
-        std::size_t operator()(const ConstantT& constant) const noexcept {
-            return constant.first ^ std::rotl<u64>(constant.second, 1);
-        }
-    };
-
-    ::Common::unordered_map<ConstantT, void*, ConstantHash> constant_info;
-    std::span<ConstantT> pool;
-    std::size_t insertion_point;
+    ConstantPool(BlockOfCode& code, size_t size) noexcept;
+    Xbyak::Address GetConstant(BlockOfCode& code, const Xbyak::AddressFrame& frame, u64 lower, u64 upper = 0) noexcept;
+    // key = identity hash, value = offset from pool.data()
+    ::Common::unordered_map<std::pair<u64, u64>, u32, boost::hash<std::pair<u64, u64>>> constant_info;
+    std::span<u128> pool;
 };
 
 }  // namespace Dynarmic::Backend::X64