1 files changed, 68 insertions, 3 deletions
diff --git a/Source/JavaScriptCore/bytecode/ExpressionRangeInfo.h b/Source/JavaScriptCore/bytecode/ExpressionRangeInfo.h
index f4949a686..855738aec 100644
--- a/Source/JavaScriptCore/bytecode/ExpressionRangeInfo.h
+++ b/Source/JavaScriptCore/bytecode/ExpressionRangeInfo.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2012, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -31,14 +31,79 @@
 namespace JSC {
 
 struct ExpressionRangeInfo {
+    // Line and column values are encoded in 1 of 3 modes depending on the size
+    // of their values. These modes are:
+    //
+    //   1. FatLine: 22-bit line, 8-bit column.
+    //   2. FatColumn: 8-bit line, 22-bit column.
+    //   3. FatLineAndColumn: 32-bit line, 32-bit column.
+    //
+    // For the first 2 modes, the line and column will be encoded in the 30-bit
+    // position field in the ExpressionRangeInfo. For the FatLineAndColumn mode,
+    // the position field will hold an index into a FatPosition vector which
+    // holds the FatPosition records with the full 32-bit line and column values.
+
+    enum {
+        FatLineMode,
+        FatColumnMode,
+        FatLineAndColumnMode
+    };
+
+    struct FatPosition {
+        uint32_t line;
+        uint32_t column;
+    };
+
+    enum {
+        FatLineModeLineShift = 8,
+        FatLineModeLineMask = (1 << 22) - 1,
+        FatLineModeColumnMask = (1 << 8) - 1,
+        FatColumnModeLineShift = 22,
+        FatColumnModeLineMask = (1 << 8) - 1,
+        FatColumnModeColumnMask = (1 << 22) - 1
+    };
+
     enum {
         MaxOffset = (1 << 7) - 1, 
-        MaxDivot = (1 << 25) - 1
+        MaxDivot = (1 << 25) - 1,
+        MaxFatLineModeLine = (1 << 22) - 1,
+        MaxFatLineModeColumn = (1 << 8) - 1,
+        MaxFatColumnModeLine = (1 << 8) - 1,
+        MaxFatColumnModeColumn = (1 << 22) - 1
     };
+
+    void encodeFatLineMode(unsigned line, unsigned column)
+    {
+        ASSERT(line <= MaxFatLineModeLine);
+        ASSERT(column <= MaxFatLineModeColumn);
+        position = ((line & FatLineModeLineMask) << FatLineModeLineShift | (column & FatLineModeColumnMask));
+    }
+
+    void encodeFatColumnMode(unsigned line, unsigned column)
+    {
+        ASSERT(line <= MaxFatColumnModeLine);
+        ASSERT(column <= MaxFatColumnModeColumn);
+        position = ((line & FatColumnModeLineMask) << FatColumnModeLineShift | (column & FatColumnModeColumnMask));
+    }
+
+    void decodeFatLineMode(unsigned& line, unsigned& column)
+    {
+        line = (position >> FatLineModeLineShift) & FatLineModeLineMask;
+        column = position & FatLineModeColumnMask;
+    }
+
+    void decodeFatColumnMode(unsigned& line, unsigned& column)
+    {
+        line = (position >> FatColumnModeLineShift) & FatColumnModeLineMask;
+        column = position & FatColumnModeColumnMask;
+    }
+
     uint32_t instructionOffset : 25;
-    uint32_t divotPoint : 25;
     uint32_t startOffset : 7;
+    uint32_t divotPoint : 25;
     uint32_t endOffset : 7;
+    uint32_t mode : 2;
+    uint32_t position : 30;
 };
 
 } // namespace JSC