SGI Freeware 1999 August

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Text File | 1998-10-28 | 13.2 KB | 661 lines

BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) NNNNAAAAMMMMEEEE B - The Perl Compiler SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS use B; DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN The B module supplies classes which allow a Perl program to delve into its own innards. It is the module used to implement the "backends" of the Perl compiler. Usage of the compiler does not require knowledge of this module: see the _O module for the user-visible part. The B module is of use to those who want to write new compiler backends. This documentation assumes that the reader knows a fair amount about perl's internals including such things as SVs, OPs and the internal symbol table and syntax tree of a program. OOOOVVVVEEEERRRRVVVVIIIIEEEEWWWW OOOOFFFF CCCCLLLLAAAASSSSSSSSEEEESSSS The C structures used by Perl's internals to hold SV and OP information (PVIV, AV, HV, ..., OP, SVOP, UNOP, ...) are modelled on a class hierarchy and the B module gives access to them via a true object hierarchy. Structure fields which point to other objects (whether types of SV or types of OP) are represented by the B module as Perl objects of the appropriate class. The bulk of the B module is the methods for accessing fields of these structures. Note that all access is read-only: you cannot modify the internals by using this module. SSSSVVVV----RRRREEEELLLLAAAATTTTEEEEDDDD CCCCLLLLAAAASSSSSSSSEEEESSSS B::IV, B::NV, B::RV, B::PV, B::PVIV, B::PVNV, B::PVMG, B::BM, B::PVLV, B::AV, B::HV, B::CV, B::GV, B::FM, B::IO. These classes correspond in the obvious way to the underlying C structures of similar names. The inheritance hierarchy mimics the underlying C "inheritance". Access methods correspond to the underlying C macros for field access, usually with the leading "class indication" prefix removed (Sv, Av, Hv, ...). The leading prefix is only left in cases where its removal would cause a clash in method name. For example, GvREFCNT stays as-is since its abbreviation would clash with the "superclass" method REFCNT (corresponding to the C function SvREFCNT). BBBB::::::::SSSSVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS REFCNT FLAGS Page 1 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) BBBB::::::::IIIIVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS IV IVX needs64bits packiv BBBB::::::::NNNNVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS NV NVX BBBB::::::::RRRRVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS RV BBBB::::::::PPPPVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS PV BBBB::::::::PPPPVVVVMMMMGGGG MMMMEEEETTTTHHHHOOOODDDDSSSS MAGIC SvSTASH BBBB::::::::MMMMAAAAGGGGIIIICCCC MMMMEEEETTTTHHHHOOOODDDDSSSS MOREMAGIC PRIVATE TYPE FLAGS OBJ PTR BBBB::::::::PPPPVVVVLLLLVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS TARGOFF TARGLEN TYPE Page 2 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) TARG BBBB::::::::BBBBMMMM MMMMEEEETTTTHHHHOOOODDDDSSSS USEFUL PREVIOUS RARE TABLE BBBB::::::::GGGGVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS NAME STASH SV IO FORM AV HV EGV CV CVGEN LINE FILEGV GvREFCNT FLAGS BBBB::::::::IIIIOOOO MMMMEEEETTTTHHHHOOOODDDDSSSS LINES PAGE PAGE_LEN LINES_LEFT Page 3 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) TOP_NAME TOP_GV FMT_NAME FMT_GV BOTTOM_NAME BOTTOM_GV SUBPROCESS IoTYPE IoFLAGS BBBB::::::::AAAAVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS FILL MAX OFF ARRAY AvFLAGS BBBB::::::::CCCCVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS STASH START ROOT GV FILEGV DEPTH PADLIST OUTSIDE XSUB XSUBANY Page 4 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) BBBB::::::::HHHHVVVV MMMMEEEETTTTHHHHOOOODDDDSSSS FILL MAX KEYS RITER NAME PMROOT ARRAY OOOOPPPP----RRRREEEELLLLAAAATTTTEEEEDDDD CCCCLLLLAAAASSSSSSSSEEEESSSS B::OP, B::UNOP, B::BINOP, B::LOGOP, B::CONDOP, B::LISTOP, B::PMOP, B::SVOP, B::GVOP, B::PVOP, B::CVOP, B::LOOP, B::COP. These classes correspond in the obvious way to the underlying C structures of similar names. The inheritance hierarchy mimics the underlying C "inheritance". Access methods correspond to the underlying C structre field names, with the leading "class indication" prefix removed (op_). BBBB::::::::OOOOPPPP MMMMEEEETTTTHHHHOOOODDDDSSSS next sibling ppaddr This returns the function name as a string (e.g. pp_add, pp_rv2av). desc This returns the op description from the global C op_desc array (e.g. "addition" "array deref"). targ type seq flags private Page 5 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) BBBB::::::::UUUUNNNNOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD first BBBB::::::::BBBBIIIINNNNOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD last BBBB::::::::LLLLOOOOGGGGOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD other BBBB::::::::CCCCOOOONNNNDDDDOOOOPPPP MMMMEEEETTTTHHHHOOOODDDDSSSS true false BBBB::::::::LLLLIIIISSSSTTTTOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD children BBBB::::::::PPPPMMMMOOOOPPPP MMMMEEEETTTTHHHHOOOODDDDSSSS pmreplroot pmreplstart pmnext pmregexp pmflags pmpermflags precomp BBBB::::::::SSSSVVVVOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD sv BBBB::::::::GGGGVVVVOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD gv BBBB::::::::PPPPVVVVOOOOPPPP MMMMEEEETTTTHHHHOOOODDDD pv Page 6 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) BBBB::::::::LLLLOOOOOOOOPPPP MMMMEEEETTTTHHHHOOOODDDDSSSS redoop nextop lastop BBBB::::::::CCCCOOOOPPPP MMMMEEEETTTTHHHHOOOODDDDSSSS label stash filegv cop_seq arybase line FFFFUUUUNNNNCCCCTTTTIIIIOOOONNNNSSSS EEEEXXXXPPPPOOOORRRRTTTTEEEEDDDD BBBBYYYY BBBB The B module exports a variety of functions: some are simple utility functions, others provide a Perl program with a way to get an initial "handle" on an internal object. main_cv Return the (faked) CV corresponding to the main part of the Perl program. main_root Returns the root op (i.e. an object in the appropriate B::OP-derived class) of the main part of the Perl program. main_start Returns the starting op of the main part of the Perl program. comppadlist Returns the AV object (i.e. in class B::AV) of the global comppadlist. sv_undef Returns the SV object corresponding to the C variable sv_undef. sv_yes Returns the SV object corresponding to the C variable sv_yes. Page 7 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) sv_no Returns the SV object corresponding to the C variable sv_no. walkoptree(OP, METHOD) Does a tree-walk of the syntax tree based at OP and calls METHOD on each op it visits. Each node is visited before its children. If walkoptree_debug (q.v.) has been called to turn debugging on then the method walkoptree_debug is called on each op before METHOD is called. walkoptree_debug(DEBUG) Returns the current debugging flag for walkoptree. If the optional DEBUG argument is non-zero, it sets the debugging flag to that. See the description of walkoptree above for what the debugging flag does. walksymtable(SYMREF, METHOD, RECURSE) Walk the symbol table starting at SYMREF and call METHOD on each symbol visited. When the walk reached package symbols "Foo::" it invokes RECURSE and only recurses into the package if that sub returns true. svref_2object(SV) Takes any Perl variable and turns it into an object in the appropriate B::OP-derived or B::SV-derived class. Apart from functions such as main_root, this is the primary way to get an initial "handle" on a internal perl data structure which can then be followed with the other access methods. ppname(OPNUM) Return the PP function name (e.g. "pp_add") of op number OPNUM. hash(STR) Returns a string in the form "0x..." representing the value of the internal hash function used by perl on string STR. cast_I32(I) Casts I to the internal I32 type used by that perl. minus_c Does the equivalent of the -c command-line option. Obviously, this is only useful in a BEGIN block or else the flag is set too late. cstring(STR) Returns a double-quote-surrounded escaped version of STR which can be used as a string in C source code. Page 8 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) class(OBJ) Returns the class of an object without the part of the classname preceding the first "::". This is used to turn "B::UNOP" into "UNOP" for example. threadsv_names In a perl compiled for threads, this returns a list of the special per-thread threadsv variables. byteload_fh(FILEHANDLE) Load the contents of FILEHANDLE as bytecode. See documentation for the BBBByyyytttteeeeccccooooddddeeee module in _B::_B_a_c_k_e_n_d for how to generate bytecode. AAAAUUUUTTTTHHHHOOOORRRR Malcolm Beattie, mbeattie@sable.ox.ac.uk Page 9 (printed 10/23/98) BBBB((((3333)))) 22223333////JJJJuuuullll////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) BBBB((((3333)))) Page 10 (printed 10/23/98)