michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- michael@0: * vim: set ts=8 sts=4 et sw=4 tw=99: michael@0: * This Source Code Form is subject to the terms of the Mozilla Public michael@0: * License, v. 2.0. If a copy of the MPL was not distributed with this michael@0: * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ michael@0: michael@0: #ifndef frontend_SourceNotes_h michael@0: #define frontend_SourceNotes_h michael@0: michael@0: #include michael@0: michael@0: #include "jstypes.h" michael@0: michael@0: typedef uint8_t jssrcnote; michael@0: michael@0: namespace js { michael@0: michael@0: /* michael@0: * Source notes generated along with bytecode for decompiling and debugging. michael@0: * A source note is a uint8_t with 5 bits of type and 3 of offset from the pc michael@0: * of the previous note. If 3 bits of offset aren't enough, extended delta michael@0: * notes (SRC_XDELTA) consisting of 2 set high order bits followed by 6 offset michael@0: * bits are emitted before the next note. Some notes have operand offsets michael@0: * encoded immediately after them, in note bytes or byte-triples. michael@0: * michael@0: * Source Note Extended Delta michael@0: * +7-6-5-4-3+2-1-0+ +7-6-5+4-3-2-1-0+ michael@0: * |note-type|delta| |1 1| ext-delta | michael@0: * +---------+-----+ +---+-----------+ michael@0: * michael@0: * At most one "gettable" note (i.e., a note of type other than SRC_NEWLINE, michael@0: * SRC_COLSPAN, SRC_SETLINE, and SRC_XDELTA) applies to a given bytecode. michael@0: * michael@0: * NB: the js_SrcNoteSpec array in BytecodeEmitter.cpp is indexed by this michael@0: * enum, so its initializers need to match the order here. michael@0: * michael@0: * Don't forget to update XDR_BYTECODE_VERSION in vm/Xdr.h for all such michael@0: * incompatible source note or other bytecode changes. michael@0: */ michael@0: #define FOR_EACH_SRC_NOTE_TYPE(M) \ michael@0: M(SRC_NULL, "null", 0) /* Terminates a note vector. */ \ michael@0: M(SRC_IF, "if", 0) /* JSOP_IFEQ bytecode is from an if-then. */ \ michael@0: M(SRC_IF_ELSE, "if-else", 1) /* JSOP_IFEQ bytecode is from an if-then-else. */ \ michael@0: M(SRC_COND, "cond", 1) /* JSOP_IFEQ is from conditional ?: operator. */ \ michael@0: M(SRC_FOR, "for", 3) /* JSOP_NOP or JSOP_POP in for(;;) loop head. */ \ michael@0: M(SRC_WHILE, "while", 1) /* JSOP_GOTO to for or while loop condition from before \ michael@0: loop, else JSOP_NOP at top of do-while loop. */ \ michael@0: M(SRC_FOR_IN, "for-in", 1) /* JSOP_GOTO to for-in loop condition from before \ michael@0: loop. */ \ michael@0: M(SRC_FOR_OF, "for-of", 1) /* JSOP_GOTO to for-of loop condition from before \ michael@0: loop. */ \ michael@0: M(SRC_CONTINUE, "continue", 0) /* JSOP_GOTO is a continue. */ \ michael@0: M(SRC_BREAK, "break", 0) /* JSOP_GOTO is a break. */ \ michael@0: M(SRC_BREAK2LABEL, "break2label", 0) /* JSOP_GOTO for 'break label'. */ \ michael@0: M(SRC_SWITCHBREAK, "switchbreak", 0) /* JSOP_GOTO is a break in a switch. */ \ michael@0: M(SRC_TABLESWITCH, "tableswitch", 1) /* JSOP_TABLESWITCH; offset points to end of switch. */ \ michael@0: M(SRC_CONDSWITCH, "condswitch", 2) /* JSOP_CONDSWITCH; 1st offset points to end of switch, \ michael@0: 2nd points to first JSOP_CASE. */ \ michael@0: M(SRC_NEXTCASE, "nextcase", 1) /* Distance forward from one CASE in a CONDSWITCH to \ michael@0: the next. */ \ michael@0: M(SRC_ASSIGNOP, "assignop", 0) /* += or another assign-op follows. */ \ michael@0: M(SRC_TRY, "try", 1) /* JSOP_TRY, offset points to goto at the end of the \ michael@0: try block. */ \ michael@0: /* All notes below here are "gettable". See SN_IS_GETTABLE below. */ \ michael@0: M(SRC_COLSPAN, "colspan", 1) /* Number of columns this opcode spans. */ \ michael@0: M(SRC_NEWLINE, "newline", 0) /* Bytecode follows a source newline. */ \ michael@0: M(SRC_SETLINE, "setline", 1) /* A file-absolute source line number note. */ \ michael@0: M(SRC_UNUSED20, "unused20", 0) /* Unused. */ \ michael@0: M(SRC_UNUSED21, "unused21", 0) /* Unused. */ \ michael@0: M(SRC_UNUSED22, "unused22", 0) /* Unused. */ \ michael@0: M(SRC_UNUSED23, "unused23", 0) /* Unused. */ \ michael@0: M(SRC_XDELTA, "xdelta", 0) /* 24-31 are for extended delta notes. */ michael@0: michael@0: enum SrcNoteType { michael@0: #define DEFINE_SRC_NOTE_TYPE(sym, name, arity) sym, michael@0: FOR_EACH_SRC_NOTE_TYPE(DEFINE_SRC_NOTE_TYPE) michael@0: #undef DEFINE_SRC_NOTE_TYPE michael@0: michael@0: SRC_LAST, michael@0: SRC_LAST_GETTABLE = SRC_TRY michael@0: }; michael@0: michael@0: static_assert(SRC_XDELTA == 24, "SRC_XDELTA should be 24"); michael@0: michael@0: /* A source note array is terminated by an all-zero element. */ michael@0: inline void michael@0: SN_MAKE_TERMINATOR(jssrcnote *sn) michael@0: { michael@0: *sn = SRC_NULL; michael@0: } michael@0: michael@0: inline bool michael@0: SN_IS_TERMINATOR(jssrcnote *sn) michael@0: { michael@0: return *sn == SRC_NULL; michael@0: } michael@0: michael@0: } // namespace js michael@0: michael@0: #define SN_TYPE_BITS 5 michael@0: #define SN_DELTA_BITS 3 michael@0: #define SN_XDELTA_BITS 6 michael@0: #define SN_TYPE_MASK (JS_BITMASK(SN_TYPE_BITS) << SN_DELTA_BITS) michael@0: #define SN_DELTA_MASK ((ptrdiff_t)JS_BITMASK(SN_DELTA_BITS)) michael@0: #define SN_XDELTA_MASK ((ptrdiff_t)JS_BITMASK(SN_XDELTA_BITS)) michael@0: michael@0: #define SN_MAKE_NOTE(sn,t,d) (*(sn) = (jssrcnote) \ michael@0: (((t) << SN_DELTA_BITS) \ michael@0: | ((d) & SN_DELTA_MASK))) michael@0: #define SN_MAKE_XDELTA(sn,d) (*(sn) = (jssrcnote) \ michael@0: ((SRC_XDELTA << SN_DELTA_BITS) \ michael@0: | ((d) & SN_XDELTA_MASK))) michael@0: michael@0: #define SN_IS_XDELTA(sn) ((*(sn) >> SN_DELTA_BITS) >= SRC_XDELTA) michael@0: #define SN_TYPE(sn) ((js::SrcNoteType)(SN_IS_XDELTA(sn) \ michael@0: ? SRC_XDELTA \ michael@0: : *(sn) >> SN_DELTA_BITS)) michael@0: #define SN_SET_TYPE(sn,type) SN_MAKE_NOTE(sn, type, SN_DELTA(sn)) michael@0: #define SN_IS_GETTABLE(sn) (SN_TYPE(sn) <= SRC_LAST_GETTABLE) michael@0: michael@0: #define SN_DELTA(sn) ((ptrdiff_t)(SN_IS_XDELTA(sn) \ michael@0: ? *(sn) & SN_XDELTA_MASK \ michael@0: : *(sn) & SN_DELTA_MASK)) michael@0: #define SN_SET_DELTA(sn,delta) (SN_IS_XDELTA(sn) \ michael@0: ? SN_MAKE_XDELTA(sn, delta) \ michael@0: : SN_MAKE_NOTE(sn, SN_TYPE(sn), delta)) michael@0: michael@0: #define SN_DELTA_LIMIT ((ptrdiff_t)JS_BIT(SN_DELTA_BITS)) michael@0: #define SN_XDELTA_LIMIT ((ptrdiff_t)JS_BIT(SN_XDELTA_BITS)) michael@0: michael@0: /* michael@0: * Offset fields follow certain notes and are frequency-encoded: an offset in michael@0: * [0,0x7f] consumes one byte, an offset in [0x80,0x7fffffff] takes four, and michael@0: * the high bit of the first byte is set. michael@0: */ michael@0: #define SN_4BYTE_OFFSET_FLAG 0x80 michael@0: #define SN_4BYTE_OFFSET_MASK 0x7f michael@0: michael@0: /* michael@0: * Negative SRC_COLSPAN offsets are rare, but can arise with for(;;) loops and michael@0: * other constructs that generate code in non-source order. They can also arise michael@0: * due to failure to update pn->pn_pos.end to be the last child's end -- such michael@0: * failures are bugs to fix. michael@0: * michael@0: * Source note offsets in general must be non-negative and less than 0x800000, michael@0: * per the above SN_4BYTE_* definitions. To encode negative colspans, we bias michael@0: * them by the offset domain size and restrict non-negative colspans to less michael@0: * than half this domain. michael@0: */ michael@0: #define SN_COLSPAN_DOMAIN ptrdiff_t(1 << 23) michael@0: michael@0: #define SN_MAX_OFFSET ((size_t)((ptrdiff_t)SN_4BYTE_OFFSET_FLAG << 24) - 1) michael@0: michael@0: #define SN_LENGTH(sn) ((js_SrcNoteSpec[SN_TYPE(sn)].arity == 0) ? 1 \ michael@0: : js_SrcNoteLength(sn)) michael@0: #define SN_NEXT(sn) ((sn) + SN_LENGTH(sn)) michael@0: michael@0: struct JSSrcNoteSpec { michael@0: const char *name; /* name for disassembly/debugging output */ michael@0: int8_t arity; /* number of offset operands */ michael@0: }; michael@0: michael@0: extern JS_FRIEND_DATA(const JSSrcNoteSpec) js_SrcNoteSpec[]; michael@0: extern JS_FRIEND_API(unsigned) js_SrcNoteLength(jssrcnote *sn); michael@0: michael@0: /* michael@0: * Get and set the offset operand identified by which (0 for the first, etc.). michael@0: */ michael@0: extern JS_FRIEND_API(ptrdiff_t) michael@0: js_GetSrcNoteOffset(jssrcnote *sn, unsigned which); michael@0: michael@0: #endif /* frontend_SourceNotes_h */