From d5c99a5b48a6cce702a1aa1e2b105ffe558d9ac9 Mon Sep 17 00:00:00 2001
From: Ryan Houdek <Sonicadvance1@gmail.com>
Date: Fri, 7 Aug 2015 22:08:57 -0500
Subject: [PATCH] Add support for a CodeBlock holding a child.

This is required to make sure two code spaces are relatively close to one another.
In this case I need the AArch64 JIT codespace and its farcode space to be within 128MB of one another for branches.
---
 Source/Core/Common/CodeBlock.h | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/Source/Core/Common/CodeBlock.h b/Source/Core/Common/CodeBlock.h
index 5699fc5385..865c4513ca 100644
--- a/Source/Core/Common/CodeBlock.h
+++ b/Source/Core/Common/CodeBlock.h
@@ -22,9 +22,19 @@ private:
 protected:
 	u8 *region;
 	size_t region_size;
+	size_t parent_region_size;
+
+	bool m_has_child;
+	bool m_is_child;
+	CodeBlock* m_child;
 
 public:
-	CodeBlock() : region(nullptr), region_size(0) {}
+	CodeBlock()
+		: region(nullptr), region_size(0), parent_region_size(0),
+		  m_has_child(false), m_is_child(false), m_child(nullptr)
+	{
+	}
+
 	virtual ~CodeBlock() { if (region) FreeCodeSpace(); }
 
 	// Call this before you generate any code.
@@ -49,6 +59,12 @@ public:
 		FreeMemoryPages(region, region_size);
 		region = nullptr;
 		region_size = 0;
+		parent_region_size = 0;
+		if (m_has_child)
+		{
+			m_child->region = nullptr;
+			m_child->region_size = 0;
+		}
 	}
 
 	bool IsInSpace(u8 *ptr) const
@@ -70,7 +86,7 @@ public:
 
 	size_t GetSpaceLeft() const
 	{
-		return region_size - (T::GetCodePtr() - region);
+		return (m_has_child ? parent_region_size : region_size) - (T::GetCodePtr() - region);
 	}
 
 	bool IsAlmostFull() const
@@ -78,5 +94,16 @@ public:
 		// This should be bigger than the biggest block ever.
 		return GetSpaceLeft() < 0x10000;
 	}
+	void AddChildCodeSpace(CodeBlock* child, size_t size)
+	{
+		_assert_msg_(DYNA_REC, !m_has_child, "Already have a child! Can't have another!");
+		m_child = child;
+		m_has_child = true;
+		m_child->m_is_child = true;
+		u8* child_region = region + region_size - size;
+		m_child->region = child_region;
+		m_child->region_size = size;
+		m_child->ResetCodePtr();
+		parent_region_size = region_size - size;
+	}
 };
-