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#pragma once
#include <vector>
#include <llvm/IR/BasicBlock.h>
#include "Stack.h"
namespace dev
{
namespace eth
{
namespace jit
{
using ProgramCounter = uint64_t; // TODO: Rename
class BasicBlock
{
public:
class LocalStack
{
public:
/// Pushes value on stack
void push(llvm::Value* _value);
/// Pops and returns top value
llvm::Value* pop();
/// Duplicates _index'th value on stack
void dup(size_t _index);
/// Swaps _index'th value on stack with a value on stack top.
/// @param _index Index of value to be swaped. Must be > 0.
void swap(size_t _index);
/// Synchronize current local stack with the EVM stack.
void synchronize(Stack& _evmStack);
private:
LocalStack(llvm::IRBuilder<>& _builder, llvm::BasicBlock* _llvmBB);
LocalStack(LocalStack const&) = delete;
void operator=(LocalStack const&) = delete;
friend BasicBlock;
/// Gets _index'th value from top (counting from 0)
llvm::Value* get(size_t _index);
/// Sets _index'th value from top (counting from 0)
void set(size_t _index, llvm::Value* _value);
std::vector<llvm::Value*>::iterator getItemIterator(size_t _index);
private:
llvm::BasicBlock* m_llvmBB;
llvm::IRBuilder<>& m_builder;
/**
* This stack contains LLVM values that correspond to items found at
* the EVM stack when the current basic block starts executing.
* Location 0 corresponds to the top of the EVM stack, location 1 is
* the item below the top and so on. The stack grows as the code
* accesses more items on the EVM stack but once a value is put on
* the stack, it will never be replaced.
*/
std::vector<llvm::Value*> m_initialStack;
/**
* This stack tracks the contents of the EVM stack as the current basic
* block executes. It may grow on both sides, as the code pushes items on
* top of the stack or changes existing items.
*/
std::vector<llvm::Value*> m_currentStack;
/**
* How many items higher is the current stack than the initial one.
* May be negative.
*/
int m_tosOffset;
};
/// Basic block name prefix. The rest is beging instruction index.
static const char* NamePrefix;
explicit BasicBlock(ProgramCounter _beginInstIdx, ProgramCounter _endInstIdx, llvm::Function* _mainFunc, llvm::IRBuilder<>& _builder);
explicit BasicBlock(std::string _name, llvm::Function* _mainFunc, llvm::IRBuilder<>& _builder);
BasicBlock(const BasicBlock&) = delete;
void operator=(const BasicBlock&) = delete;
operator llvm::BasicBlock*() { return m_llvmBB; }
llvm::BasicBlock* llvm() { return m_llvmBB; }
ProgramCounter begin() { return m_beginInstIdx; }
ProgramCounter end() { return m_endInstIdx; }
LocalStack& localStack() { return m_stack; }
/// Optimization: propagates values between local stacks in basic blocks
/// to avoid excessive pushing/popping on the EVM stack.
static void linkLocalStacks(std::vector<BasicBlock*> _basicBlocks, llvm::IRBuilder<>& _builder);
/// Prints local stack and block instructions to stderr.
/// Useful for calling in a debugger session.
void dump();
void dump(std::ostream& os, bool _dotOutput = false);
private:
ProgramCounter const m_beginInstIdx;
ProgramCounter const m_endInstIdx;
llvm::BasicBlock* const m_llvmBB;
/// Basic black state vector (stack) - current/end values and their positions on stack
/// @internal Must be AFTER m_llvmBB
LocalStack m_stack;
};
}
}
}