180 lines
3.8 KiB
C
180 lines
3.8 KiB
C
/*****************************************************************************
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*
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* gc.c
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*
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* The garbage-collector.
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*
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*****************************************************************************/
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#include "m4.h"
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#ifndef Gc
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/*****************************************************************************
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*
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* WalkPv
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*
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* Mark an arbitrary object.
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*
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*****************************************************************************/
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void STDCALL
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WalkPv(PVOID pv)
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{
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if (pv) {
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PAR par = parPv(pv);
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Assert(par->tm == g_tmNow - 1);
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par->tm = g_tmNow;
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AssertPar(par); /* This catches double-references */
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}
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}
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/*****************************************************************************
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*
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* WalkPtok
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*
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* Walk a token. The token itself is not walked, but its contents are.
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* (Because tokens are typically embedded inside other objects.)
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*
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*****************************************************************************/
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void STDCALL
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WalkPtok(PTOK ptok)
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{
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if (ptok) {
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if (!fStaticPtok(ptok)) {
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Assert(fHeapPtok(ptok));
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WalkPv(ptchPtok(ptok));
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}
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}
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}
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/*****************************************************************************
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*
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* WalkPval
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*
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* Walk a value.
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*
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*****************************************************************************/
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void STDCALL
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WalkPval(PVAL pval)
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{
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if (pval) {
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WalkPv(pval);
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WalkPtok(&pval->tok);
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}
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}
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/*****************************************************************************
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*
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* WalkPmac
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*
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* Walk a macro.
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*
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*****************************************************************************/
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void STDCALL
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WalkPmac(PMAC pmac)
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{
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if (pmac) {
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PVAL pval;
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WalkPv(pmac);
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WalkPtok(&pmac->tokName);
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for (pval = pmac->pval; pval; pval = pval->pvalPrev) {
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WalkPval(pval);
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}
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}
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}
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/*****************************************************************************
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*
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* WalkPstm
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*
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* Walk a stream.
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*
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* The compiler knows how to optimize tail recursion.
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*
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*****************************************************************************/
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void STDCALL
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WalkPstm(PSTM pstm)
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{
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if (pstm) {
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WalkPv(pstm);
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WalkPv(pstm->ptchMin);
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WalkPv(pstm->ptchName);
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WalkPstm(pstm->pstmNext);
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}
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}
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/*****************************************************************************
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*
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* WalkPdiv
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*
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* Walk a diversion.
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*
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*****************************************************************************/
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void STDCALL
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WalkPdiv(PDIV pdiv)
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{
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if (pdiv) {
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WalkPv(pdiv);
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WalkPv(pdiv->ptchMin);
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WalkPv(pdiv->ptchName);
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}
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}
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/*****************************************************************************
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*
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* Sweep
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*
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* Sweep through memory, looking for garbage.
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*
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*****************************************************************************/
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void STDCALL
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Sweep(void)
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{
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PAR par;
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for (par = parHead->parNext; par != parHead; par = par->parNext) {
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Assert(par->tm == g_tmNow); /* Memory should have been walked! */
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}
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}
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/*****************************************************************************
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*
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* Gc
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*
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* The garbage collector is mark-and-sweep.
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*
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* Walk all the root objects, recursing into sub-objects, until everything
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* is marked with the current (fake) timestamp. Then walk through the
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* memory arenas. Anything not marked with the current timestamp is garbage.
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*
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*****************************************************************************/
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TM g_tmNow;
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void STDCALL
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Gc(void)
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{
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g_tmNow++;
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if (mphashpmac) {
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WalkPv(mphashpmac);
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EachMacroOp(WalkPmac);
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}
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WalkPv(rgtokArgv);
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WalkPv(rgcellEstack);
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WalkPstm(g_pstmCur);
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WalkPdiv(g_pdivArg);
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WalkPdiv(g_pdivExp);
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WalkPdiv(g_pdivOut);
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WalkPdiv(g_pdivErr);
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WalkPdiv(g_pdivNul);
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Sweep();
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}
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#endif
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