Mercurial > illumos > illumos-gate
view usr/src/cmd/mdb/common/mdb/mdb_vcb.c @ 14167:7ac6fb740bcf
3946 ::gcore (fix sparc build)
author | Christopher Siden <chris.siden@delphix.com> |
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date | Tue, 27 Aug 2013 10:51:34 -0800 |
parents | 68f95e015346 |
children |
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/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" /* * In order to implement walk iteration variables (that is, ::walk walk varname) * we need to keep track of the active walk variables as the pipeline is * processed. Each variable is tracked using a VCB (Variable Control Block) * that keeps a pointer to the variable in the MDB variable hash table, as * well as an addrvec (array of values) and parent pointer. Each command in * the pipeline keeps its own list of VCBs, and these are inherited from left * to right in the pipeline. The diagram shows an example pipeline and the * contents of c_addrv and VCBs at each stage: * * > ::walk proc p | ::map .+1 | ::eval '<p=K' * * vcb(p) vcb(p) * 0<- parent <----------- parent * c_addrv addrv c_addrv addrv * 123 123 124 123 * 456 456 457 456 * 789 789 790 789 * * Then the first command (::walk) begins life with no VCBs. It then creates * a new VCB for the rest of the pipeline and adds it to the next command's * VCB list (::map). Before ::map is executed, it will first pass along a set * of VCBs to its "child" ::eval. The important operations defined for VCBs * are as follows: * * (1) mdb_vcb_inherit - Prior to processing each command (pipeline stage), the * debugger calls the inherit routine to cause the next command to inherit the * VCBs from the current command. The inherit routine allocates a new VCB * containing a pointer to the same variable, and sets its parent pointer to * point back to the parent VCB. A VCB created by ::walk has a NULL parent * pointer indicating that it inherits its value from dot. * * (2) mdb_vcb_propagate - Prior to invoking the dcmd associated with a command, * the debugger propagates the next value stored in the VCB to its variable. * The VCB stores the values the variable should assume (that is, the values * of the variable that correspond to the value stored in the command's c_addrv) * in an addrvec in the VCB itself. * * (3) mdb_vcb_update - As each dcmd executes, it produces output for the next * stage in the pipeline. The *next* stage of the pipeline's mdb_cmd_t has * already inherited the necessary VCBs in step (1), and so we just need to * record the current value of the variable into the VCB's addrv. In the base * case (the first pipeline stage), the variable is not yet set, so we want * to store the current value of dot (produced by ::walk's callback) into the * addrv. This value is passed in directly from the parsing code as a parameter * before the parser resets dot itself. For subsequent pipeline stages, we * need to store into addrv the value the variable previously held when the * dcmd that produced this new value of dot was executed. This value is * stored in the corresponding index of the parent VCB's addrv. * * (4) mdb_vcb_find - Given an mdb_var_t, determines if there already exists a * vcb for this variable, and if so returns it. This allows us to avoid * re-creating a vcb every time through a walk, such as: * * > ::walk proc p | ::walk proc v | ::eval "<p=Kn" * * In this case, we don't want to create a new vcb for 'v' every time we execute * the second walk. * * Unfortunately, determining the addrv index is complicated by the fact that * pipes involve the asynchronous execution of the dcmds and the parser. This * asynchrony means that the parser may not actually consume the output of a * given dcmd until long after it has completed, and thus when the parser is * ready to reset dot, it does not know what addrv index produced this value. * We work around this problem by explicitly flushing the pipeline after each * dcmd invocation if VCBs are active. This does impact performance, so we * may need to re-evaluate in the future if pipelines are producing huge * amounts of data and a large number of VCBs are active simultaneously. */ #include <mdb/mdb_frame.h> #include <mdb/mdb_debug.h> #include <mdb/mdb_modapi.h> #include <mdb/mdb_vcb.h> #include <mdb/mdb.h> mdb_vcb_t * mdb_vcb_create(mdb_var_t *v) { mdb_vcb_t *vcb = mdb_zalloc(sizeof (mdb_vcb_t), UM_SLEEP); vcb->vc_var = v; return (vcb); } void mdb_vcb_destroy(mdb_vcb_t *vcb) { mdb_dprintf(MDB_DBG_DSTK, "delete vcb %p (%s)\n", (void *)vcb, mdb_nv_get_name(vcb->vc_var)); mdb_addrvec_destroy(&vcb->vc_addrv); mdb_free(vcb, sizeof (mdb_vcb_t)); } void mdb_vcb_propagate(mdb_vcb_t *vcb) { while (vcb != NULL) { mdb_addrvec_t *adp = &vcb->vc_addrv; ASSERT(vcb->vc_adnext < adp->ad_nelems); mdb_nv_set_value(vcb->vc_var, adp->ad_data[vcb->vc_adnext++]); vcb = vcb->vc_link; } } void mdb_vcb_purge(mdb_vcb_t *vcb) { while (vcb != NULL) { mdb_vcb_t *n = vcb->vc_link; mdb_vcb_destroy(vcb); vcb = n; } } void mdb_vcb_inherit(mdb_cmd_t *src, mdb_cmd_t *dst) { mdb_vcb_t *vc1, *vc2; for (vc1 = src->c_vcbs; vc1 != NULL; vc1 = vc1->vc_link) { vc2 = mdb_vcb_create(vc1->vc_var); vc2->vc_parent = vc1; vc2->vc_link = dst->c_vcbs; dst->c_vcbs = vc2; } } void mdb_vcb_insert(mdb_vcb_t *vcb, mdb_frame_t *fp) { if (fp->f_pcmd != NULL) { mdb_cmd_t *cp = fp->f_pcmd; mdb_dprintf(MDB_DBG_DSTK, "insert vcb %p (%s)\n", (void *)vcb, mdb_nv_get_name(vcb->vc_var)); ASSERT(vcb->vc_link == NULL); vcb->vc_link = cp->c_vcbs; cp->c_vcbs = vcb; } } void mdb_vcb_update(struct mdb_frame *fp, uintptr_t value) { mdb_vcb_t *vcb; for (vcb = fp->f_pcmd->c_vcbs; vcb != NULL; vcb = vcb->vc_link) { if (vcb->vc_parent != NULL) { mdb_addrvec_t *adp = &vcb->vc_parent->vc_addrv; adp->ad_ndx = vcb->vc_parent->vc_adnext - 1; ASSERT(adp->ad_ndx < adp->ad_nelems); value = adp->ad_data[adp->ad_ndx++]; } mdb_addrvec_unshift(&vcb->vc_addrv, value); } } mdb_vcb_t * mdb_vcb_find(mdb_var_t *var, mdb_frame_t *fp) { mdb_vcb_t *vcb; if (fp->f_pcmd != NULL) { vcb = fp->f_pcmd->c_vcbs; while (vcb != NULL) { if (vcb->vc_var == var) return (vcb); vcb = vcb->vc_link; } } return (NULL); }