diff options
Diffstat (limited to 'c.c')
| -rw-r--r-- | c.c | 94 |
1 files changed, 56 insertions, 38 deletions
@@ -2,8 +2,9 @@ #include "lex.h" #include "ir.h" +/** C compiler state **/ struct comp { - struct parser pr; + struct lexer lx; struct env *env; struct arena *fnarena, *exarena; struct span fnblkspan; @@ -11,9 +12,9 @@ struct comp { struct block *loopbreak, *loopcont; }; -#define peek(Cm,Tk) lexpeek(&(Cm)->pr,Tk) -#define lex(Cm,Tk) lex(&(Cm)->pr,Tk) - +/** Parsing helper functions **/ +#define peek(Cm,Tk) lexpeek(&(Cm)->lx,Tk) +#define lex(Cm,Tk) lex(&(Cm)->lx,Tk) static bool match(struct comp *cm, struct token *tk, enum toktag t) { @@ -23,7 +24,6 @@ match(struct comp *cm, struct token *tk, enum toktag t) } return 0; } - static bool expect(struct comp *cm, enum toktag t, const char *s) { @@ -36,7 +36,6 @@ expect(struct comp *cm, enum toktag t, const char *s) } return 1; } - static struct token expectdie(struct comp *cm, enum toktag t, const char *s) { @@ -46,13 +45,9 @@ expectdie(struct comp *cm, enum toktag t, const char *s) return tk; } -enum declkind { - DTOPLEVEL, - DFUNCPARAM, - DFUNCVAR, - DFIELD, - DCASTEXPR, -}; +/**************************************/ +/* Data structures for C declarations */ +/**************************************/ enum storageclass { SCNONE, @@ -77,20 +72,41 @@ struct decl { }; }; +enum declkind { + DTOPLEVEL, + DFUNCPARAM, + DFUNCVAR, + DFIELD, + DCASTEXPR, +}; + +/* Since a declaration can have multiple declarators, and we need to process + * each one individually, the declaration parser is a state machine + * (conceptually a generator coroutine); the state is zero-initialized (except + * for the .kind field), each call to pdecl yields the next individual decl, + * st.more indicates whether there are more decls left to parse (the coroutine + * has yielded), or this declaration list is done (the coroutine has finalized) + */ struct declstate { enum declkind kind; union type base; enum storageclass scls; enum qualifier qual; uint align; - bool more, varini, funcdef, tagdecl; - const char **pnames; - struct span *pspans; + bool more, /* caller should keep calling pdecl to get next decl */ + varini, /* caller should parse an initializer ('=' <ini>) and + call pdecl() to advance state before checking .more */ + funcdef, /* caller should parse an func definition ('{' <body> '}'). + the declaration list is finished. */ + tagdecl; + const char **pnames; /* param names for function definition */ + struct span *pspans; /* param spans ditto */ }; - static struct decl pdecl(struct declstate *st, struct comp *cm); + static struct decl *finddecl(struct comp *cm, const char *name); +/* next token starts a decl? */ static bool isdecltok(struct comp *cm) { @@ -111,13 +127,13 @@ isdecltok(struct comp *cm) } -/*******/ -/* ENV */ -/*******/ +/**********************************/ +/* Environment (scope) management */ +/**********************************/ static struct decl envdeclsbuf[1<<10]; static vec_of(struct decl) envdecls = VINIT(envdeclsbuf, arraylength(envdeclsbuf)); -struct tagged { +struct tagged { /* a tagged type declaration */ union type ty; struct span span; }; @@ -186,6 +202,7 @@ envaddtagged(struct env *env, union type ty, const struct span *span) return &envtagged.p[envtagged.n - 1]; } +/* like enviterdecl */ static inline bool envitertagged(struct tagged **l, struct env *env) { @@ -276,13 +293,9 @@ deftagged(struct comp *cm, struct span *span, enum typetag tt, const char *name, return envaddtagged(cm->env, ty.t ? ty : mktagtype(name, &td), span)->ty; } -/*******************/ -/*** EXPRESSIONS ***/ -/*******************/ - -/**********************/ -/* EXPR TYPE CHECKING */ -/**********************/ +/*********************/ +/* Expr Typechecking */ +/*********************/ #define iszero(ex) ((ex).t == ENUMLIT && (ex).u == 0) @@ -567,7 +580,7 @@ bintypecheck(const struct span *span, enum toktag tt, struct expr *lhs, struct e } /****************/ -/* EXPR PARSING */ +/* Expr Parsing */ /****************/ #define mkexpr(t_,span_,ty_,...) ((struct expr){.t=(t_), .ty=(ty_), .span=(span_), __VA_ARGS__}) @@ -921,7 +934,8 @@ Postfix: lex(cm, &tk); ek = bintab[tk.t].t; if (ek != ECOND) { - bool leftassoc = (bintab[tk.t].k & BCSET) == 0; /* only the assignment operators are right-associative */ + /* only the assignment operators are right-associative */ + bool leftassoc = (bintab[tk.t].k & BCSET) == 0; /* ex OP rhs */ span.sl = tk.span.sl; span.ex = ex.span.ex; @@ -971,9 +985,9 @@ commaexpr(struct comp *cm) return exprparse(cm, 1); } -/*********/ -/* -> IR */ -/*********/ +/*****************/ +/* IR Generation */ +/*****************/ static union ref expraddr(struct function *, const struct expr *); static union ref compileexpr(struct function *, const struct expr *, bool discard); @@ -1591,6 +1605,10 @@ compileexpr(struct function *fn, const struct expr *ex, bool discard) } } +/************************************/ +/* Statements parsing & compilation */ +/************************************/ + static void stmtterm(struct comp *cm) { @@ -1976,9 +1994,9 @@ function(struct comp *cm, struct function *fn, const char **pnames, const struct } } -/********/ -/* DECL */ -/********/ +/*****************/ +/* Decls Parsing */ +/*****************/ static union type buildagg(struct comp *cm, enum typetag tt, const char *name, int id) @@ -2699,7 +2717,7 @@ docomp(struct comp *cm) while (peek(cm, tk) != TKEOF) { struct expr ini; - struct declstate st = { DTOPLEVEL, }; + struct declstate st = { DTOPLEVEL }; do { int nerr = nerror; struct decl decl = pdecl(&st, cm); @@ -2749,7 +2767,7 @@ ccomp(const char *file) static union { char m[sizeof(struct arena) + N]; struct arena *_align; } amem[2]; struct comp cm = {0}; - initparser(&cm.pr, file, &cm.exarena); + initlexer(&cm.lx, file, &cm.exarena); cm.fnarena = (void *)amem[0].m; cm.fnarena->cap = N; cm.exarena = (void *)amem[1].m; |