JitArm64: Keep track of free code regions and reuse space when possible

JitArm64 port of 306a5e6.

Source/Core/Core/PowerPC/JitArm64/Jit.cpp

@@ -9,6 +9,7 @@
 #include "Common/CommonTypes.h"
 #include "Common/Logging/Log.h"
 #include "Common/MathUtil.h"
+#include "Common/MsgHandler.h"
 #include "Common/PerformanceCounter.h"
 #include "Common/StringUtil.h"
 
@@ -68,6 +69,8 @@ void JitArm64::Init()
 
   AllocStack();
   GenerateAsm();
+
+  ResetFreeMemoryRanges();
 }
 
 bool JitArm64::HandleFault(uintptr_t access_address, SContext* ctx)
@@ -125,12 +128,24 @@ void JitArm64::ClearCache()
   m_fault_to_handler.clear();
 
   blocks.Clear();
+  blocks.ClearRangesToFree();
   const Common::ScopedJITPageWriteAndNoExecute enable_jit_page_writes;
   ClearCodeSpace();
   m_far_code.ClearCodeSpace();
   UpdateMemoryAndExceptionOptions();
 
   GenerateAsm();
+
+  ResetFreeMemoryRanges();
+}
+
+void JitArm64::ResetFreeMemoryRanges()
+{
+  // Set the near and far code regions as unused.
+  m_free_ranges_near.clear();
+  m_free_ranges_near.insert(GetWritableCodePtr(), GetWritableCodeEnd());
+  m_free_ranges_far.clear();
+  m_free_ranges_far.insert(m_far_code.GetWritableCodePtr(), m_far_code.GetWritableCodeEnd());
 }
 
 void JitArm64::Shutdown()
@@ -576,7 +591,12 @@ void JitArm64::SingleStep()
   pExecAddr();
 }
 
-void JitArm64::Jit(u32)
+void JitArm64::Jit(u32 em_address)
+{
+  Jit(em_address, true);
+}
+
+void JitArm64::Jit(u32 em_address, bool clear_cache_and_retry_on_failure)
 {
   if (m_cleanup_after_stackfault)
   {
@@ -588,14 +608,31 @@ void JitArm64::Jit(u32)
 #endif
   }
 
-  if (IsAlmostFull() || m_far_code.IsAlmostFull() || SConfig::GetInstance().bJITNoBlockCache)
-  {
+  if (SConfig::GetInstance().bJITNoBlockCache)
     ClearCache();
+
+  // Check if any code blocks have been freed in the block cache and transfer this information to
+  // the local rangesets to allow overwriting them with new code.
+  for (auto range : blocks.GetRangesToFreeNear())
+  {
+    auto first_fastmem_area = m_fault_to_handler.upper_bound(range.first);
+    auto last_fastmem_area = first_fastmem_area;
+    auto end = m_fault_to_handler.end();
+    while (last_fastmem_area != end && last_fastmem_area->first <= range.second)
+      ++last_fastmem_area;
+    m_fault_to_handler.erase(first_fastmem_area, last_fastmem_area);
+
+    m_free_ranges_near.insert(range.first, range.second);
   }
+  for (auto range : blocks.GetRangesToFreeFar())
+  {
+    m_free_ranges_far.insert(range.first, range.second);
+  }
+  blocks.ClearRangesToFree();
+
   const Common::ScopedJITPageWriteAndNoExecute enable_jit_page_writes;
 
   std::size_t block_size = m_code_buffer.size();
-  const u32 em_address = PowerPC::ppcState.pc;
 
   if (SConfig::GetInstance().bEnableDebugging)
   {
@@ -618,12 +655,75 @@ void JitArm64::Jit(u32)
     return;
   }
 
-  JitBlock* b = blocks.AllocateBlock(em_address);
-  DoJit(em_address, b, nextPC);
-  blocks.FinalizeBlock(*b, jo.enableBlocklink, code_block.m_physical_addresses);
+  if (SetEmitterStateToFreeCodeRegion())
+  {
+    u8* near_start = GetWritableCodePtr();
+    u8* far_start = m_far_code.GetWritableCodePtr();
+
+    JitBlock* b = blocks.AllocateBlock(em_address);
+    if (DoJit(em_address, b, nextPC))
+    {
+      // Code generation succeeded.
+
+      // Mark the memory regions that this code block uses as used in the local rangesets.
+      u8* near_end = GetWritableCodePtr();
+      if (near_start != near_end)
+        m_free_ranges_near.erase(near_start, near_end);
+      u8* far_end = m_far_code.GetWritableCodePtr();
+      if (far_start != far_end)
+        m_free_ranges_far.erase(far_start, far_end);
+
+      // Store the used memory regions in the block so we know what to mark as unused when the
+      // block gets invalidated.
+      b->near_begin = near_start;
+      b->near_end = near_end;
+      b->far_begin = far_start;
+      b->far_end = far_end;
+
+      blocks.FinalizeBlock(*b, jo.enableBlocklink, code_block.m_physical_addresses);
+      return;
+    }
+  }
+
+  if (clear_cache_and_retry_on_failure)
+  {
+    // Code generation failed due to not enough free space in either the near or far code regions.
+    // Clear the entire JIT cache and retry.
+    WARN_LOG(POWERPC, "flushing code caches, please report if this happens a lot");
+    ClearCache();
+    Jit(em_address, false);
+    return;
+  }
+
+  PanicAlertT("JIT failed to find code space after a cache clear. This should never happen. Please "
+              "report this incident on the bug tracker. Dolphin will now exit.");
+  exit(-1);
 }
 
-void JitArm64::DoJit(u32 em_address, JitBlock* b, u32 nextPC)
+bool JitArm64::SetEmitterStateToFreeCodeRegion()
+{
+  // Find the largest free memory blocks and set code emitters to point at them.
+  // If we can't find a free block return false instead, which will trigger a JIT cache clear.
+  auto free_near = m_free_ranges_near.by_size_begin();
+  if (free_near == m_free_ranges_near.by_size_end())
+  {
+    WARN_LOG(POWERPC, "Failed to find free memory region in near code region.");
+    return false;
+  }
+  SetCodePtr(free_near.from(), free_near.to());
+
+  auto free_far = m_free_ranges_far.by_size_begin();
+  if (free_far == m_free_ranges_far.by_size_end())
+  {
+    WARN_LOG(POWERPC, "Failed to find free memory region in far code region.");
+    return false;
+  }
+  m_far_code.SetCodePtr(free_far.from(), free_far.to());
+
+  return true;
+}
+
+bool JitArm64::DoJit(u32 em_address, JitBlock* b, u32 nextPC)
 {
   js.isLastInstruction = false;
   js.firstFPInstructionFound = false;
@@ -870,9 +970,21 @@ void JitArm64::DoJit(u32 em_address, JitBlock* b, u32 nextPC)
     WriteExit(nextPC);
   }
 
+  if (HasWriteFailed() || m_far_code.HasWriteFailed())
+  {
+    if (HasWriteFailed())
+      WARN_LOG(POWERPC, "JIT ran out of space in near code region during code generation.");
+    if (m_far_code.HasWriteFailed())
+      WARN_LOG(POWERPC, "JIT ran out of space in far code region during code generation.");
+
+    return false;
+  }
+
   b->codeSize = (u32)(GetCodePtr() - start);
   b->originalSize = code_block.m_num_instructions;
 
   FlushIcache();
   m_far_code.FlushIcache();
+
+  return true;
 }

Source/Core/Core/PowerPC/JitArm64/Jit.h

@@ -7,6 +7,8 @@
 #include <map>
 #include <tuple>
 
+#include <rangeset/rangesizeset.h>
+
 #include "Common/Arm64Emitter.h"
 
 #include "Core/PowerPC/CPUCoreBase.h"
@@ -39,7 +41,8 @@ public:
   void Run() override;
   void SingleStep() override;
 
-  void Jit(u32) override;
+  void Jit(u32 em_address) override;
+  void Jit(u32 em_address, bool clear_cache_and_retry_on_failure);
 
   const char* GetName() const override { return "JITARM64"; }
 
@@ -226,7 +229,11 @@ protected:
   Arm64Gen::FixupBranch CheckIfSafeAddress(Arm64Gen::ARM64Reg addr, Arm64Gen::ARM64Reg tmp1,
                                            Arm64Gen::ARM64Reg tmp2);
 
-  void DoJit(u32 em_address, JitBlock* b, u32 nextPC);
+  bool DoJit(u32 em_address, JitBlock* b, u32 nextPC);
+
+  // Finds a free memory region and sets the near and far code emitters to point at that region.
+  // Returns false if no free memory region can be found for either of the two.
+  bool SetEmitterStateToFreeCodeRegion();
 
   void DoDownCount();
   void Cleanup();
@@ -234,6 +241,8 @@ protected:
   void AllocStack();
   void FreeStack();
 
+  void ResetFreeMemoryRanges();
+
   // AsmRoutines
   void GenerateAsm();
   void GenerateCommonAsm();
@@ -304,4 +313,7 @@ protected:
   u8* m_stack_base = nullptr;
   u8* m_stack_pointer = nullptr;
   u8* m_saved_stack_pointer = nullptr;
+
+  HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_near;
+  HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_far;
 };

Source/Core/Core/PowerPC/JitArm64/JitArm64Cache.cpp

@@ -12,6 +12,12 @@ JitArm64BlockCache::JitArm64BlockCache(JitBase& jit) : JitBaseBlockCache{jit}
 {
 }
 
+void JitArm64BlockCache::Init()
+{
+  JitBaseBlockCache::Init();
+  ClearRangesToFree();
+}
+
 void JitArm64BlockCache::WriteLinkBlock(Arm64Gen::ARM64XEmitter& emit,
                                         const JitBlock::LinkData& source, const JitBlock* dest)
 {
@@ -75,3 +81,29 @@ void JitArm64BlockCache::WriteDestroyBlock(const JitBlock& block)
     emit.BRK(0x123);
   emit.FlushIcache();
 }
+
+void JitArm64BlockCache::DestroyBlock(JitBlock& block)
+{
+  JitBaseBlockCache::DestroyBlock(block);
+
+  if (block.near_begin != block.near_end)
+    m_ranges_to_free_on_next_codegen_near.emplace_back(block.near_begin, block.near_end);
+  if (block.far_begin != block.far_end)
+    m_ranges_to_free_on_next_codegen_far.emplace_back(block.far_begin, block.far_end);
+}
+
+const std::vector<std::pair<u8*, u8*>>& JitArm64BlockCache::GetRangesToFreeNear() const
+{
+  return m_ranges_to_free_on_next_codegen_near;
+}
+
+const std::vector<std::pair<u8*, u8*>>& JitArm64BlockCache::GetRangesToFreeFar() const
+{
+  return m_ranges_to_free_on_next_codegen_far;
+}
+
+void JitArm64BlockCache::ClearRangesToFree()
+{
+  m_ranges_to_free_on_next_codegen_near.clear();
+  m_ranges_to_free_on_next_codegen_far.clear();
+}

Source/Core/Core/PowerPC/JitArm64/JitArm64Cache.h

@@ -3,6 +3,8 @@
 
 #pragma once
 
+#include <vector>
+
 #include "Common/Arm64Emitter.h"
 #include "Core/PowerPC/JitCommon/JitCache.h"
 
@@ -15,10 +17,22 @@ class JitArm64BlockCache : public JitBaseBlockCache
 public:
   explicit JitArm64BlockCache(JitBase& jit);
 
+  void Init() override;
+
+  void DestroyBlock(JitBlock& block) override;
+
+  const std::vector<std::pair<u8*, u8*>>& GetRangesToFreeNear() const;
+  const std::vector<std::pair<u8*, u8*>>& GetRangesToFreeFar() const;
+
+  void ClearRangesToFree();
+
   void WriteLinkBlock(Arm64Gen::ARM64XEmitter& emit, const JitBlock::LinkData& source,
                       const JitBlock* dest = nullptr);
 
 private:
   void WriteLinkBlock(const JitBlock::LinkData& source, const JitBlock* dest) override;
   void WriteDestroyBlock(const JitBlock& block) override;
+
+  std::vector<std::pair<u8*, u8*>> m_ranges_to_free_on_next_codegen_near;
+  std::vector<std::pair<u8*, u8*>> m_ranges_to_free_on_next_codegen_far;
 };