ARM: Fix literal pool handling for breakpoints in debugger....

src/assembler.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 123 matching lines @@
 // below, the first byte listed it at the highest address, and successive
 // bytes in the record are at progressively lower addresses.
 //
 // Encoding
 //
 // The most common modes are given single-byte encodings.  Also, it is
 // easy to identify the type of reloc info and skip unwanted modes in
 // an iteration.
 //
 // The encoding relies on the fact that there are fewer than 14
-// different non-compactly encoded relocation modes.
+// different relocation modes using standard non-compact encoding.
 //
 // The first byte of a relocation record has a tag in its low 2 bits:
 // Here are the record schemes, depending on the low tag and optional higher
 // tags.
 //
 // Low tag:
 //   00: embedded_object:      [6-bit pc delta] 00
 //
 //   01: code_target:          [6-bit pc delta] 01
 //
@@ skipping 11 matching lines @@
 //
 //  Long record format:
 //    4-bit middle_tag:
 //      0000 - 1100 : Short record for RelocInfo::Mode middle_tag + 2
 //         (The middle_tag encodes rmode - RelocInfo::LAST_COMPACT_ENUM,
 //          and is between 0000 and 1100)
 //        The format is:
 //                              00 [4 bit middle_tag] 11 followed by
 //                              00 [6 bit pc delta]
 //
-//      1101: not used (would allow one more relocation mode to be added)
+//      1101: constant pool. Used on ARM only for now.
+//        The format is:       11 1101 11
+//                             signed int (size of the constant pool).
 //      1110: long_data_record
 //        The format is:       [2-bit data_type_tag] 1110 11
 //                             signed intptr_t, lowest byte written first
 //                             (except data_type code_target_with_id, which
 //                             is followed by a signed int, not intptr_t.)
 //
 //      1111: long_pc_jump
 //        The format is:
 //          pc-jump:             00 1111 11,
 //                               00 [6 bits pc delta]
 //        or
 //          pc-jump (variable length):
 //                               01 1111 11,
 //                               [7 bits data] 0
 //                                  ...
 //                               [7 bits data] 1
 //               (Bits 6..31 of pc delta, with leading zeroes
 //                dropped, and last non-zero chunk tagged with 1.)
 
 
-const int kMaxRelocModes = 14;
+const int kMaxStandardNonCompactModes = 14;
 
 const int kTagBits = 2;
 const int kTagMask = (1 << kTagBits) - 1;
 const int kExtraTagBits = 4;
 const int kLocatableTypeTagBits = 2;
 const int kSmallDataBits = kBitsPerByte - kLocatableTypeTagBits;
 
 const int kEmbeddedObjectTag = 0;
 const int kCodeTargetTag = 1;
 const int kLocatableTag = 2;
@@ skipping 13 matching lines @@
 const int kLastChunkTag = 1;
 
 
 const int kDataJumpExtraTag = kPCJumpExtraTag - 1;
 
 const int kCodeWithIdTag = 0;
 const int kNonstatementPositionTag = 1;
 const int kStatementPositionTag = 2;
 const int kCommentTag = 3;
 
+const int kConstPoolExtraTag = kPCJumpExtraTag - 2;
+const int kConstPoolTag = 3;
+
 
 uint32_t RelocInfoWriter::WriteVariableLengthPCJump(uint32_t pc_delta) {
   // Return if the pc_delta can fit in kSmallPCDeltaBits bits.
   // Otherwise write a variable length PC jump for the bits that do
   // not fit in the kSmallPCDeltaBits bits.
   if (is_uintn(pc_delta, kSmallPCDeltaBits)) return pc_delta;
   WriteExtraTag(kPCJumpExtraTag, kVariableLengthPCJumpTopTag);
   uint32_t pc_jump = pc_delta >> kSmallPCDeltaBits;
   ASSERT(pc_jump > 0);
   // Write kChunkBits size chunks of the pc_jump.
@@ skipping 37 matching lines @@
 
 void RelocInfoWriter::WriteExtraTaggedIntData(int data_delta, int top_tag) {
   WriteExtraTag(kDataJumpExtraTag, top_tag);
   for (int i = 0; i < kIntSize; i++) {
     *--pos_ = static_cast<byte>(data_delta);
     // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
     data_delta = data_delta >> kBitsPerByte;
   }
 }
 
+void RelocInfoWriter::WriteExtraTaggedConstPoolData(int data) {
+  WriteExtraTag(kConstPoolExtraTag, kConstPoolTag);
+  for (int i = 0; i < kIntSize; i++) {
+    *--pos_ = static_cast<byte>(data);
+    // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
+    data = data >> kBitsPerByte;
+  }
+}
+
 void RelocInfoWriter::WriteExtraTaggedData(intptr_t data_delta, int top_tag) {
   WriteExtraTag(kDataJumpExtraTag, top_tag);
   for (int i = 0; i < kIntptrSize; i++) {
     *--pos_ = static_cast<byte>(data_delta);
     // Signed right shift is arithmetic shift.  Tested in test-utils.cc.
     data_delta = data_delta >> kBitsPerByte;
   }
 }
 
 
 void RelocInfoWriter::Write(const RelocInfo* rinfo) {
 #ifdef DEBUG
   byte* begin_pos = pos_;
 #endif
   ASSERT(rinfo->pc() - last_pc_ >= 0);
-  ASSERT(RelocInfo::NUMBER_OF_MODES - RelocInfo::LAST_COMPACT_ENUM <=
-         kMaxRelocModes);
+  ASSERT(RelocInfo::LAST_STANDARD_NONCOMPACT_ENUM - RelocInfo::LAST_COMPACT_ENUM
+         <= kMaxStandardNonCompactModes);
   // Use unsigned delta-encoding for pc.
   uint32_t pc_delta = static_cast<uint32_t>(rinfo->pc() - last_pc_);
   RelocInfo::Mode rmode = rinfo->rmode();
 
   // The two most common modes are given small tags, and usually fit in a byte.
   if (rmode == RelocInfo::EMBEDDED_OBJECT) {
     WriteTaggedPC(pc_delta, kEmbeddedObjectTag);
   } else if (rmode == RelocInfo::CODE_TARGET) {
     WriteTaggedPC(pc_delta, kCodeTargetTag);
     ASSERT(begin_pos - pos_ <= RelocInfo::kMaxCallSize);
@@ skipping 25 matching lines @@
       // Otherwise, use costly encoding.
       WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
       WriteExtraTaggedIntData(pos_delta, pos_type_tag);
     }
     last_position_ = static_cast<int>(rinfo->data());
   } else if (RelocInfo::IsComment(rmode)) {
     // Comments are normally not generated, so we use the costly encoding.
     WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
     WriteExtraTaggedData(rinfo->data(), kCommentTag);
     ASSERT(begin_pos - pos_ >= RelocInfo::kMinRelocCommentSize);
+  } else if (RelocInfo::IsConstPool(rmode)) {
+      WriteExtraTaggedPC(pc_delta, kPCJumpExtraTag);
+      WriteExtraTaggedConstPoolData(rinfo->data());
   } else {
     ASSERT(rmode > RelocInfo::LAST_COMPACT_ENUM);
     int saved_mode = rmode - RelocInfo::LAST_COMPACT_ENUM;
     // For all other modes we simply use the mode as the extra tag.
     // None of these modes need a data component.
     ASSERT(saved_mode < kPCJumpExtraTag && saved_mode < kDataJumpExtraTag);
     WriteExtraTaggedPC(pc_delta, saved_mode);
   }
   last_pc_ = rinfo->pc();
 #ifdef DEBUG
@@ skipping 30 matching lines @@
 void RelocIterator::AdvanceReadId() {
   int x = 0;
   for (int i = 0; i < kIntSize; i++) {
     x |= static_cast<int>(*--pos_) << i * kBitsPerByte;
   }
   last_id_ += x;
   rinfo_.data_ = last_id_;
 }
 
 
+void RelocIterator::AdvanceReadConstPoolData() {
+  int x = 0;
+  for (int i = 0; i < kIntSize; i++) {
+    x |= static_cast<int>(*--pos_) << i * kBitsPerByte;
+  }
+  rinfo_.data_ = x;
+}
+
+
 void RelocIterator::AdvanceReadPosition() {
   int x = 0;
   for (int i = 0; i < kIntSize; i++) {
     x |= static_cast<int>(*--pos_) << i * kBitsPerByte;
   }
   last_position_ += x;
   rinfo_.data_ = last_position_;
 }
 
 
@@ skipping 83 matching lines @@
                locatable_tag == kStatementPositionTag);
         if (mode_mask_ & RelocInfo::kPositionMask) {
           ReadTaggedPosition();
           if (SetMode(GetPositionModeFromTag(locatable_tag))) return;
         }
       }
     } else {
       ASSERT(tag == kDefaultTag);
       int extra_tag = GetExtraTag();
       if (extra_tag == kPCJumpExtraTag) {
-        int top_tag = GetTopTag();
-        if (top_tag == kVariableLengthPCJumpTopTag) {
+        if (GetTopTag() == kVariableLengthPCJumpTopTag) {
           AdvanceReadVariableLengthPCJump();
         } else {
           AdvanceReadPC();
         }
       } else if (extra_tag == kDataJumpExtraTag) {
         int locatable_tag = GetTopTag();
         if (locatable_tag == kCodeWithIdTag) {
           if (SetMode(RelocInfo::CODE_TARGET_WITH_ID)) {
             AdvanceReadId();
             return;
           }
           Advance(kIntSize);
         } else if (locatable_tag != kCommentTag) {
           ASSERT(locatable_tag == kNonstatementPositionTag ||
                  locatable_tag == kStatementPositionTag);
           if (mode_mask_ & RelocInfo::kPositionMask) {
             AdvanceReadPosition();
             if (SetMode(GetPositionModeFromTag(locatable_tag))) return;
           } else {
             Advance(kIntSize);
           }
         } else {
           ASSERT(locatable_tag == kCommentTag);
           if (SetMode(RelocInfo::COMMENT)) {
             AdvanceReadData();
             return;
           }
           Advance(kIntptrSize);
         }
+      } else if ((extra_tag == kConstPoolExtraTag) &&
+                 (GetTopTag() == kConstPoolTag)) {
+        if (SetMode(RelocInfo::CONST_POOL)) {
+          AdvanceReadConstPoolData();
+          return;
+        }
+        Advance(kIntSize);
       } else {
         AdvanceReadPC();
         int rmode = extra_tag + RelocInfo::LAST_COMPACT_ENUM;
         if (SetMode(static_cast<RelocInfo::Mode>(rmode))) return;
       }
     }
   }
   done_ = true;
 }
 
@@ skipping 62 matching lines @@
     case RelocInfo::COMMENT:
       return "comment";
     case RelocInfo::POSITION:
       return "position";
     case RelocInfo::STATEMENT_POSITION:
       return "statement position";
     case RelocInfo::EXTERNAL_REFERENCE:
       return "external reference";
     case RelocInfo::INTERNAL_REFERENCE:
       return "internal reference";
+    case RelocInfo::CONST_POOL:
+      return "constant pool";
     case RelocInfo::DEBUG_BREAK_SLOT:
 #ifndef ENABLE_DEBUGGER_SUPPORT
       UNREACHABLE();
 #endif
       return "debug break slot";
     case RelocInfo::NUMBER_OF_MODES:
       UNREACHABLE();
       return "number_of_modes";
   }
   return "unknown relocation type";
@@ skipping 65 matching lines @@
       ASSERT(code->address() == HeapObject::cast(found)->address());
       break;
     }
     case RUNTIME_ENTRY:
     case JS_RETURN:
     case COMMENT:
     case POSITION:
     case STATEMENT_POSITION:
     case EXTERNAL_REFERENCE:
     case INTERNAL_REFERENCE:
+    case CONST_POOL:
     case DEBUG_BREAK_SLOT:
     case NONE:
       break;
     case NUMBER_OF_MODES:
       UNREACHABLE();
       break;
   }
 }
 #endif  // DEBUG
 
@@ skipping 620 matching lines @@
     assembler_->RecordRelocInfo(RelocInfo::POSITION, state_.current_position);
     state_.written_position = state_.current_position;
     written = true;
   }
 
   // Return whether something was written.
   return written;
 }
 
 } }  // namespace v8::internal