Backend/A64: Add Dolphin's ARM emitter

src/CMakeLists.txt

@@ -322,6 +322,13 @@ if (ARCHITECTURE_x86_64)
     else()
         target_sources(dynarmic PRIVATE backend/x64/exception_handler_generic.cpp)
     endif()
+elseif(ARCHITECTURE_Aarch64)
+    target_sources(dynarmic PRIVATE
+         backend/A64/emitter/a64_emitter.cpp
+         backend/A64/emitter/a64_emitter.h
+         backend/A64/emitter/arm_common.h
+         backend/A64/emitter/code_block.h
+    )
 else()
     message(FATAL_ERROR "Unsupported architecture")
 endif()

src/backend/A64/emitter/arm_common.h

@@ -0,0 +1,28 @@
+// Copyright 2014 Dolphin Emulator Project / 2018 dynarmic project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "common/common_types.h"
+
+namespace Dynarmic::BackendA64 {
+enum CCFlags {
+    CC_EQ = 0,     // Equal
+    CC_NEQ,        // Not equal
+    CC_CS,         // Carry Set
+    CC_CC,         // Carry Clear
+    CC_MI,         // Minus (Negative)
+    CC_PL,         // Plus
+    CC_VS,         // Overflow
+    CC_VC,         // No Overflow
+    CC_HI,         // Unsigned higher
+    CC_LS,         // Unsigned lower or same
+    CC_GE,         // Signed greater than or equal
+    CC_LT,         // Signed less than
+    CC_GT,         // Signed greater than
+    CC_LE,         // Signed less than or equal
+    CC_AL,         // Always (unconditional) 14
+    CC_HS = CC_CS, // Alias of CC_CS  Unsigned higher or same
+    CC_LO = CC_CC, // Alias of CC_CC  Unsigned lower
+};
+const u32 NO_COND = 0xE0000000;
+} // namespace Dynarmic::BackendA64

src/backend/A64/emitter/code_block.h

@@ -0,0 +1,126 @@
+// Copyright 2014 Dolphin Emulator Project / 2018 dynarmic project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstddef>
+#include <vector>
+
+#include <sys/mman.h>
+
+#include "common/assert.h"
+#include "common/common_types.h"
+
+namespace Dynarmic::BackendA64 {
+// Everything that needs to generate code should inherit from this.
+// You get memory management for free, plus, you can use all emitter functions
+// without having to prefix them with gen-> or something similar. Example
+// implementation: class JIT : public CodeBlock<ARMXEmitter> {}
+template <class T>
+class CodeBlock : public T {
+private:
+    // A privately used function to set the executable RAM space to something
+    // invalid. For debugging usefulness it should be used to set the RAM to a
+    // host specific breakpoint instruction
+    virtual void PoisonMemory() = 0;
+
+protected:
+    u8* region = nullptr;
+    // Size of region we can use.
+    size_t region_size = 0;
+    // Original size of the region we allocated.
+    size_t total_region_size = 0;
+
+    bool m_is_child = false;
+    std::vector<CodeBlock*> m_children;
+
+public:
+    CodeBlock() = default;
+    virtual ~CodeBlock() {
+        if (region)
+            FreeCodeSpace();
+    }
+    CodeBlock(const CodeBlock&) = delete;
+    CodeBlock& operator=(const CodeBlock&) = delete;
+    CodeBlock(CodeBlock&&) = delete;
+    CodeBlock& operator=(CodeBlock&&) = delete;
+
+    // Call this before you generate any code.
+    void AllocCodeSpace(size_t size) {
+        region_size = size;
+        total_region_size = size;
+        void* ptr =
+            mmap(nullptr, size, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANON | MAP_PRIVATE, -1, 0);
+        if (ptr == MAP_FAILED)
+            ptr = nullptr;
+        region = static_cast<u8*>(ptr);
+        T::SetCodePtr(region);
+    }
+
+    // Always clear code space with breakpoints, so that if someone accidentally
+    // executes uninitialized, it just breaks into the debugger.
+    void ClearCodeSpace() {
+        PoisonMemory();
+        ResetCodePtr();
+    }
+
+    // Call this when shutting down. Don't rely on the destructor, even though
+    // it'll do the job.
+    void FreeCodeSpace() {
+        ASSERT(!m_is_child);
+        ASSERT(munmap(region, total_region_size) != 0);
+        region = nullptr;
+        region_size = 0;
+        total_region_size = 0;
+        for (CodeBlock* child : m_children) {
+            child->region = nullptr;
+            child->region_size = 0;
+            child->total_region_size = 0;
+        }
+    }
+
+    bool IsInSpace(const u8* ptr) const {
+        return ptr >= region && ptr < (region + region_size);
+    }
+    // Cannot currently be undone. Will write protect the entire code region.
+    // Start over if you need to change the code (call FreeCodeSpace(),
+    // AllocCodeSpace()).
+    void WriteProtect() {
+        ASSERT(mprotect(region, region_size, PROT_READ | PROT_EXEC) != 0);
+    }
+    void ResetCodePtr() {
+        T::SetCodePtr(region);
+    }
+    size_t GetSpaceLeft() const {
+        ASSERT(static_cast<size_t>(T::GetCodePtr() - region) < region_size);
+        return region_size - (T::GetCodePtr() - region);
+    }
+
+    bool IsAlmostFull() const {
+        // This should be bigger than the biggest block ever.
+        return GetSpaceLeft() < 0x10000;
+    }
+
+    bool HasChildren() const {
+        return region_size != total_region_size;
+    }
+
+    u8* AllocChildCodeSpace(size_t child_size) {
+        ASSERT_MSG(child_size < GetSpaceLeft(), "Insufficient space for child allocation.");
+        u8* child_region = region + region_size - child_size;
+        region_size -= child_size;
+        return child_region;
+    }
+
+    void AddChildCodeSpace(CodeBlock* child, size_t child_size) {
+        u8* child_region = AllocChildCodeSpace(child_size);
+        child->m_is_child = true;
+        child->region = child_region;
+        child->region_size = child_size;
+        child->total_region_size = child_size;
+        child->ResetCodePtr();
+        m_children.emplace_back(child);
+    }
+};
+} // namespace Dynarmic::BackendA64

src/common/math_util.h

@@ -44,4 +44,9 @@ u8 RecipEstimate(u64 a);
  */
 u8 RecipSqrtEstimate(u64 a);
 
+template <typename T>
+constexpr bool IsPow2(T imm){
+    return imm > 0 && (imm & (imm - 1)) == 0;
+}
+
 } // namespace Dynarmic::Common

src/frontend/A64/translate/impl/impl.cpp

@@ -3,9 +3,9 @@
  * SPDX-License-Identifier: 0BSD
  */
 
+#include "frontend/A64/translate/impl/impl.h"
 #include "common/bit_util.h"
 #include "frontend/ir/terminal.h"
-#include "frontend/A64/translate/impl/impl.h"
 
 namespace Dynarmic::A64 {