scc

simple c99 compiler
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commit 2051da00e5d1a5232fa186eebdd1a662eb770fad
parent e6d33b692fd3237ec7197c2214ae74b476849dd8
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Mon, 12 Dec 2016 13:55:58 +0100

[cc1] Use circular double list for hash collisions

This new data structure will allow us to remove random
types from any point of the list without problems.

Diffstat:
Mcc1/cc1.h | 3++-
Mcc1/main.c | 1+
Mcc1/types.c | 29++++++++++++++++++++++++-----
3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/cc1/cc1.h b/cc1/cc1.h @@ -284,7 +284,6 @@ struct type { unsigned char align; /* align of the type */ Type *type; /* base type */ Symbol *tag; /* symbol of the strug tag */ - Type *next; /* next element in the hash */ union { Type **pars; /* Function type parameters */ Symbol **fields; /* fields of aggregate type */ @@ -293,6 +292,7 @@ struct type { unsigned char rank; /* convertion rank */ TINT elem; /* number of type parameters */ } n; + Type *h_prev, *h_next; /* hash pointers */ }; struct symbol { @@ -356,6 +356,7 @@ extern Type *mktype(Type *tp, int op, TINT nelem, Type *data[]); extern Type *duptype(Type *base); extern struct limits *getlimits(Type *tp); extern void typesize(Type *tp); +extern void itypes(void); /* symbol.c */ extern void dumpstab(char *msg); diff --git a/cc1/main.c b/cc1/main.c @@ -58,6 +58,7 @@ main(int argc, char *argv[]) int i; atexit(clean); + itypes(); icpp(); ilex(); diff --git a/cc1/types.c b/cc1/types.c @@ -72,6 +72,19 @@ static struct limits limits[][4] = { } }; +static Type typetab[NR_TYPE_HASH]; + +void +itypes() +{ + Type *tp; + + for (tp = typetab; tp < &typetab[NR_TYPE_HASH]; ++tp) { + tp->h_next = tp; + tp->h_prev = tp; + } +} + struct limits * getlimits(Type *tp) { @@ -242,8 +255,7 @@ typesize(Type *tp) Type * mktype(Type *tp, int op, TINT nelem, Type *pars[]) { - static Type *typetab[NR_TYPE_HASH]; - Type **tbl, type; + Type *tbl, *h_next, type; unsigned t; Type *bp; int c, k_r = 0; @@ -296,7 +308,7 @@ mktype(Type *tp, int op, TINT nelem, Type *pars[]) t = (op ^ (uintptr_t) tp>>3) & NR_TYPE_HASH-1; tbl = &typetab[t]; - for (bp = *tbl; bp; bp = bp->next) { + for (bp = tbl; bp->h_next != tbl; bp = bp->h_next) { if (eqtype(bp, &type, 0) && op != STRUCT && op != UNION) { /* * pars was allocated by the caller @@ -313,8 +325,15 @@ mktype(Type *tp, int op, TINT nelem, Type *pars[]) bp = xmalloc(sizeof(*bp)); *bp = type; bp->id = newid(); - bp->next = *tbl; - return *tbl = bp; + + /* insert the new type in the circular double list */ + h_next = tbl->h_next; + bp->h_next = h_next; + bp->h_prev = h_next->h_prev; + h_next->h_prev = bp; + tbl->h_next = bp; + + return bp; } int