Log uncompiled assembly

src/browser/starter.js

@@ -232,6 +232,7 @@ function V86Starter(options)
         "_coverage_log": (fn_name_offset, num_blocks, visited_block) => {
             coverage_logger.log(fn_name_offset, num_blocks, visited_block);
         },
+        "_log_uncompiled_code": (start, end) => cpu.log_uncompiled_code(start, end),
 
         // see https://github.com/kripken/emscripten/blob/incoming/src/library.js
         "_atan2": Math.atan2,

src/config.js

@@ -23,6 +23,12 @@ var LOG_ALL_IO = false;
  */
 var DUMP_GENERATED_WASM = false;
 
+/**
+ * @const
+ * Note: Needs to be enabled here and in const.h
+ */
+var DUMP_UNCOMPILED_ASSEMBLY = false;
+
 
 var LOG_LEVEL = LOG_ALL & ~LOG_PS2 & ~LOG_PIT & ~LOG_VIRTIO & ~LOG_9P & ~LOG_PIC &
                           ~LOG_DMA & ~LOG_SERIAL & ~LOG_NET & ~LOG_FLOPPY & ~LOG_DISK & ~LOG_VGA;

src/cpu.js

@@ -1253,6 +1253,7 @@ if(PROFILING)
 }
 
 var seen_code = {};
+var seen_code_uncompiled = {};
 
 CPU.prototype.codegen_finalize = function(cache_index, virtual_start, start, end)
 {
@@ -1272,7 +1273,7 @@ CPU.prototype.codegen_finalize = function(cache_index, virtual_start, start, end
 
             if((start ^ end) & ~0xFFF)
             {
-                dbg_log("truncated disassembly");
+                dbg_log("truncated disassembly start=" + h(start >>> 0) + " end=" + h(end >>> 0));
                 end = (start | 0xFFF) + 1; // until the end of the page
             }
 
@@ -1323,6 +1324,41 @@ CPU.prototype.codegen_finalize = function(cache_index, virtual_start, start, end
     //dbg_log("code block from " + h(before >>> 0) + " to " + h(after >>> 0));
 };
 
+CPU.prototype.log_uncompiled_code = function(start, end)
+{
+    if(!DEBUG || !DUMP_UNCOMPILED_ASSEMBLY)
+    {
+        return;
+    }
+
+    if((seen_code_uncompiled[start] || 0) < 100)
+    {
+        seen_code_uncompiled[start] = (seen_code_uncompiled[start] || 0) + 1;
+
+        end += 8; // final jump is not included
+
+        if((start ^ end) & ~0xFFF)
+        {
+            dbg_log("truncated disassembly start=" + h(start >>> 0) + " end=" + h(end >>> 0));
+            end = (start | 0xFFF) + 1; // until the end of the page
+        }
+
+        if(end < start) end = start;
+
+        dbg_assert(end >= start);
+
+        const buffer = new Uint8Array(end - start);
+
+        for(let i = start; i < end; i++)
+        {
+            buffer[i - start] = this.read8(i);
+        }
+
+        dbg_log("Uncompiled code:");
+        this.debug.dump_code(this.is_32[0] ? 1 : 0, buffer, start);
+    }
+};
+
 CPU.prototype.dbg_log = function()
 {
     dbg_log("from wasm: " + [].join.call(arguments));

src/native/const.h

@@ -190,4 +190,7 @@
 #define ENABLE_PROFILER 0
 #define ENABLE_PROFILER_TIMES 0
 
+// Note: needs to be enabled here and in config.js
+#define DUMP_UNCOMPILED_ASSEMBLY 0
+
 #define LOG_PAGE_FAULTS 0

src/native/cpu.c

@@ -533,12 +533,25 @@ static void jit_run_interpreted(int32_t phys_addr)
 
     jit_jump = false;
 
+#if DUMP_UNCOMPILED_ASSEMBLY
+    int32_t start_eip = phys_addr;
+    int32_t end_eip = start_eip;
+#endif
+
     assert(!in_mapped_range(phys_addr));
     int32_t opcode = mem8[phys_addr];
     (*instruction_pointer)++;
     (*timestamp_counter)++;
     run_instruction(opcode | !!*is_32 << 8);
 
+#if DUMP_UNCOMPILED_ASSEMBLY
+    if(!jit_jump)
+    {
+        *previous_ip = *instruction_pointer;
+        end_eip = get_phys_eip();
+    }
+#endif
+
     while(!jit_jump)
     {
         previous_ip[0] = instruction_pointer[0];
@@ -546,8 +559,19 @@ static void jit_run_interpreted(int32_t phys_addr)
 
         int32_t opcode = read_imm8();
         run_instruction(opcode | !!*is_32 << 8);
+
+#if DUMP_UNCOMPILED_ASSEMBLY
+        if(!jit_jump)
+        {
+            *previous_ip = *instruction_pointer;
+            end_eip = get_phys_eip();
+        }
+#endif
     }
 
+#if DUMP_UNCOMPILED_ASSEMBLY
+    log_uncompiled_code(start_eip, end_eip);
+#endif
     profiler_end(P_RUN_INTERPRETED);
 }
 

src/native/js_imports.h

@@ -26,6 +26,7 @@ extern int32_t set_cr0(int32_t);
 extern int32_t verr(int32_t);
 extern int32_t verw(int32_t);
 extern void codegen_finalize(int32_t, int32_t, int32_t, int32_t);
+extern void log_uncompiled_code(int32_t, int32_t);
 extern void cpl_changed(void);
 extern void cpuid(void);
 extern void enter16(int32_t, int32_t);