EVMC tracing for interpreter

Author: chfast

evmc

@@ -21,6 +21,36 @@ EVM::EVM(evmc_instance* _instance) noexcept : m_instance(_instance)
         m_instance->set_option(m_instance, pair.first.c_str(), pair.second.c_str());
 }
 
+EVMC::EVMC(evmc_instance* _instance) : EVM(_instance)
+{
+    static constexpr auto tracer = [](evmc_tracer_context * context, int depth, int step,
+        size_t code_offset, evmc_status_code status_code, int64_t gas_left, size_t stack_num_items,
+        const evmc_uint256be* pushed_stack_item, size_t memory_size,
+        size_t changed_memory_offset, size_t changed_memory_size,
+        const uint8_t* changed_memory) noexcept {
+
+        EVMC* evmc = reinterpret_cast<EVMC*>(context);
+
+        // TODO: It might be easier to just pass instruction from VM.
+        InstructionInfo instrInfo = instructionInfo(static_cast<Instruction>(evmc->m_code[code_offset]));
+
+        std::cerr << "EVMC " << depth << " " << step << " " << code_offset << " " << instrInfo.name << " " << status_code
+                  << " " << gas_left << " " << stack_num_items;
+
+        if (pushed_stack_item)
+            std::cerr << " +[" << fromEvmC(*pushed_stack_item) << "]";
+
+        std::cerr << " " << memory_size << "\n";
+
+        (void)changed_memory_offset;
+        (void)changed_memory_size;
+        (void)changed_memory_size;
+        (void)changed_memory;
+    };
+
+    _instance->set_tracer(_instance, tracer, reinterpret_cast<evmc_tracer_context*>(this));
+}
+
 owning_bytes_ref EVMC::exec(u256& io_gas, ExtVMFace& _ext, const OnOpFunc& _onOp)
 {
     assert(_ext.envInfo().number() >= 0);
@@ -35,6 +65,8 @@ owning_bytes_ref EVMC::exec(u256& io_gas, ExtVMFace& _ext, const OnOpFunc& _onOp
     assert(_ext.envInfo().gasLimit() <= int64max);
     assert(_ext.depth <= static_cast<size_t>(std::numeric_limits<int32_t>::max()));
 
+    m_code = bytesConstRef{&_ext.code};
+
     auto gas = static_cast<int64_t>(io_gas);
     EVM::Result r = execute(_ext, gas);
 

libevm/EVMC.cpp

@@ -91,9 +91,12 @@ class EVM
 class EVMC : public EVM, public VMFace
 {
 public:
-    explicit EVMC(evmc_instance* _instance) : EVM(_instance) {}
+    explicit EVMC(evmc_instance* _instance);
 
     owning_bytes_ref exec(u256& io_gas, ExtVMFace& _ext, OnOpFunc const& _onOp) final;
+
+private:
+    bytesConstRef m_code;
 };
 }
 }

libevm/EVMC.h

@@ -91,10 +91,36 @@ VM::VM()
         aleth_get_buildinfo()->project_version,
         ::destroy,
         ::execute,
+        setTracer,
         nullptr,
     }
 {}
 
+void VM::setTracer(
+    evmc_instance* _instance, evmc_trace_callback _callback, evmc_tracer_context* _context) noexcept
+{
+    auto vm = static_cast<dev::eth::VM*>(_instance);
+    vm->m_trace = _callback;
+    vm->m_traceContext = _context;
+}
+
+void VM::trace() noexcept
+{
+    if (m_trace)
+    {
+        InstructionMetric const& metric = c_metrics[static_cast<size_t>(m_OP)];
+        evmc_uint256be topStackItem;
+        evmc_uint256be const* pushedStackItem = nullptr;
+        if (metric.ret == 1)
+        {
+            topStackItem = toEvmC(m_SPP[0]);
+            pushedStackItem = &topStackItem;
+        }
+        m_trace(m_traceContext, m_message->depth, m_step++, m_PC, EVMC_SUCCESS, m_io_gas,
+            m_stackEnd - m_SPP, pushedStackItem, m_mem.size(), 0, 0, nullptr);
+    }
+}
+
 uint64_t VM::memNeed(u256 _offset, u256 _size)
 {
     return toInt63(_size ? u512(_offset) + _size : u512(0));
@@ -387,6 +413,7 @@ void VM::interpretCases()
             updateIOGas();
 
             m_SPP[0] = (u256)*(h256 const*)(m_mem.data() + (unsigned)m_SP[0]);
+            trace();
         }
         NEXT
 
@@ -397,6 +424,7 @@ void VM::interpretCases()
             updateIOGas();
 
             *(h256*)&m_mem[(unsigned)m_SP[0]] = (h256)m_SP[1];
+            trace();
         }
         NEXT
 
@@ -1530,11 +1558,14 @@ void VM::interpretCases()
             // get val at two-byte offset into const pool and advance pc by one-byte remainder
             TRACE_OP(2, m_PC, m_OP);
             unsigned off;
-            ++m_PC;
-            off = m_code[m_PC++] << 8;
-            off |= m_code[m_PC++];
-            m_PC += m_code[m_PC];
+            uint64_t pc = m_PC;
+            ++pc;
+            off = m_code[pc++] << 8;
+            off |= m_code[pc++];
+            pc += m_code[pc];
             m_SPP[0] = m_pool[off];
+            trace();
+            m_PC = pc;
             TRACE_VAL(2, "Retrieved pooled const", m_SPP[0]);
 #else
             throwBadInstruction();
@@ -1546,9 +1577,9 @@ void VM::interpretCases()
         {
             ON_OP();
             updateIOGas();
-            ++m_PC;
-            m_SPP[0] = m_code[m_PC];
-            ++m_PC;
+            m_SPP[0] = m_code[m_PC + 1];
+            trace();
+            m_PC += 2;
         }
         CONTINUE
 
@@ -1594,6 +1625,8 @@ void VM::interpretCases()
             // bytes to handle "out of code" push data here.
             for (++m_PC; numBytes--; ++m_PC)
                 m_SPP[0] = (m_SPP[0] << 8) | m_code[m_PC];
+
+            trace();
         }
         CONTINUE
 
@@ -1722,6 +1755,7 @@ void VM::interpretCases()
 
             updateSSGas();
             updateIOGas();
+            trace();
 
             evmc_uint256be key = toEvmC(m_SP[0]);
             evmc_uint256be value = toEvmC(m_SP[1]);

libevm/VM.cpp

@@ -92,7 +92,6 @@ class VM : public evmc_instance
     void copyCode(int);
     typedef void (VM::*MemFnPtr)();
     MemFnPtr m_bounce = nullptr;
-    uint64_t m_nSteps = 0;
 
     // return bytes
     owning_bytes_ref m_output;
@@ -138,6 +137,15 @@ class VM : public evmc_instance
     uint64_t m_newMemSize = 0;
     uint64_t m_copyMemSize = 0;
 
+    // EVMC tracing.
+    int m_step = 0;
+    evmc_trace_callback m_trace = nullptr;
+    evmc_tracer_context* m_traceContext = nullptr;
+    static void setTracer(evmc_instance* _instance, evmc_trace_callback _callback,
+        evmc_tracer_context* _context) noexcept;
+
+    void trace() noexcept;
+
     // initialize interpreter
     void initEntry();
     void optimize();