refstate.txt

来自「开放源码的编译器open watcom 1.6.0版的源代码」· 文本 代码 · 共 78 行

 .WATCOM_references Specification  draft 6
 
 In TAG_compile_unit:
 
     AT_WATCOM_references_start	0x4083
 
     A constant that indicates the offset into the .WATCOM_references
     section which defines the references for this compile unit.
 
 .WATCOM_references section:
	 May contain references for more than one compile unit.  The portion
	 for each compile unit begins with a 4 byte length that does not
	 include the length itself.
 
 The references section encodes a matrix with the columns
 
     user	-- the DIE that is doing the referecing
|    usee	-- the DIE being referenced
     file	-- the file the reference occurs in
     line	-- the line the reference occurs at
     column	-- the column the reference occurs at
|    refType	-- the type of the reference.

|    Initially defined values for refType are:
|	0 - undefined
|	1 - throw - given scope throws usee type
|	2 - goto - given scope has goto usee label
|
|    This set will likely expand with time, to include other
|    flavors of 'using'.
 
 The references section is compressed by using a finite push down automata
 with a stack called scope.  The top of scope is the user register; the
 remaining registers are the same as the columns above.
 
 The initial state of the machine is:
 
     scope	empty
|    usee	undefined
     file	1
     line	1
     column	1
|    refType	0
 
 The input is a stream of bytes... which are the following opcodes:
 
 0x01	REF_BEGIN_SCOPE	push next DWORD onto scope stack
 
 0x02	REF_END_SCOPE	pop scope stack
 
 0x03	REF_SET_FILE	ULEB128 read into the file register
 
 0x04	REF_SET_LINE	ULEB128 read into the line register
						 ? and implicit set column 0
 
|0x09	REF_SET_TYPE	ULEB128 read into the refType register
|
 0x05	REF_SET_COLUMN	ULEB128 read into the column register
 
 0x06	REF_ADD_LINE	LEB128 added to the line register
						 ? and implicit set column 0
 
 0x07	REF_ADD_COLUMN	LEB128 added to the column register
 
 0x08	REF_COPY	append a row to the matrix with the current value
			 of the registers
 
 0x10	REF_CODE_BASE	opcodes >= REF_CODE_BASE are decoded as follows:
 
			 #define REF_COLUMN_RANGE	80
 
			 v = opcode - REF_CODE_BASE;
			 line += v / REF_COLUMN_RANGE;
			 column += v % REF_COLUMN_RANGE;
			 dependant = next DWORD;
			 
			 followed by an implicit REF_COPY.