Extend assembler with ability to produce comments for the generated code.

runtime/vm/disassembler_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/disassembler.h"
 
 #if !defined(_WIN32)  // Disassembler is not yet supported under WIN32.
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #endif
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 #include "platform/assert.h"
 
 namespace dart {
 
 void Disassembler::Disassemble(uword start,
                                uword end,
-                               DisassemblyFormatter* formatter) {
+                               DisassemblyFormatter* formatter,
+                               const Code::Comments& comments) {
   // First print the actual addresses so that we know where in memory this is
   // being disassembled from.
   formatter->Print("start: %p  end: %p\n", start, end);
 
 #if !defined(_WIN32)  // Disassembler is not yet supported under WIN32.
   // Write code block to tmp file.
   char tmp[] = "/tmp/codeblock.XXXXXX";
   int fd = mkstemp(tmp);
   if (fd < 0) {
     int errsv = errno;
@@ skipping 42 matching lines @@
 #else
   const char* header = "<.data>:\n";
 #endif
   char* header_pos = NULL;
   while (header_pos == NULL && fgets(line, sizeof(line), output) != NULL) {
     header_pos = strstr(line, header);
     if (header_pos != NULL) {
       formatter->Print("%s", header_pos + strlen(header));
     }
   }
+
+
+  int comment_finger = 0;
   while (fgets(line, sizeof(line), output) != NULL) {
-    formatter->Print("%s", line);
+    char* tab = strchr(line, '\t');
+    if (tab != NULL) {
+      *tab = '\0';
+      intptr_t offset = 0;
+      sscanf(line, "%p", reinterpret_cast<void**>(&offset));  // NOLINT
+      while (comment_finger < comments.Length() &&
+             comments.PCOffsetAt(comment_finger) <= offset) {
+        formatter->Print("        ;; %s\n",
+                         comments.CommentAt(comment_finger).ToCString());
+        comment_finger++;
+      }
+
+      formatter->Print("%016p %08x %s", start + offset, offset, tab + 1);
+    }
   }
   pclose(output);
 
   // Delete tmp files.
   remove(tmp);
 #if defined(__APPLE__)
   char tmp_o[32];
   snprintf(tmp_o, sizeof(tmp_o), "%s.o", tmp);
   remove(tmp_o);
 #endif
 #endif  // !defined(_WIN32)
 }
 
 
 int Disassembler::DecodeInstruction(char* hexa_buffer, intptr_t hexa_size,
                                     char* human_buffer, intptr_t human_size,
                                     uword pc) {
   UNIMPLEMENTED();
   return 0;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64