Add support for built-in variable args

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Eugene Loh <eugene.loh@oracle.com>

libdtrace/dt_cg.c

@@ -3619,23 +3619,27 @@ dt_cg_assoc_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	TRACE_REGSET("    assoc_op: End  ");
 }
 
+/*
+ * Currently, this code is only used for the args[] and uregs[] arrays.
+ */
 static void
 dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 {
-	dt_probe_t *prp = yypcb->pcb_probe;
-	uintmax_t saved = dnp->dn_args->dn_value;
-	dt_ident_t *idp = dnp->dn_ident;
-
-	ssize_t base;
-	size_t size;
-	int n;
+	dt_probe_t	*prp = yypcb->pcb_probe;
+	uintmax_t	saved = dnp->dn_args->dn_value;
+	dt_ident_t	*idp = dnp->dn_ident;
+	dt_ident_t	*fidp = dt_dlib_get_func(yypcb->pcb_hdl, "dt_get_bvar");
+	size_t		size;
+	int		n;
 
 	assert(dnp->dn_kind == DT_NODE_VAR);
-	assert(!(idp->di_flags & DT_IDFLG_LOCAL));
+	assert(!(idp->di_flags & (DT_IDFLG_TLS | DT_IDFLG_LOCAL)));
 
 	assert(dnp->dn_args->dn_kind == DT_NODE_INT);
 	assert(dnp->dn_args->dn_list == NULL);
 
+	assert(fidp != NULL);
+
 	/*
 	 * If this is a reference in the args[] array, temporarily modify the
 	 * array index according to the static argument mapping (if any),
@@ -3653,18 +3657,39 @@ dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 		dnp->dn_args->dn_value = prp->mapping[saved];
 	}
 
+	/*
+	 * Mark the identifier as referenced by the current DIFO.  If it is an
+	 * orphaned identifier, we also need to mark the primary identifier
+	 * (global identifier with the same name).
+	 *
+	 * We can safely replace idp with the primary identifier at this point
+	 * because they have the same id.
+	 */
+	idp->di_flags |= DT_IDFLG_DIFR;
+	if (idp->di_flags & DT_IDFLG_ORPHAN) {
+		idp = dt_idhash_lookup(yypcb->pcb_hdl->dt_globals, "args");
+		assert(idp != NULL);
+		idp->di_flags |= DT_IDFLG_DIFR;
+	}
+
 	dt_cg_node(dnp->dn_args, dlp, drp);
 	dnp->dn_args->dn_value = saved;
-
 	dnp->dn_reg = dnp->dn_args->dn_reg;
 
-	if (idp->di_flags & DT_IDFLG_TLS)
-		base = 0x2000;
-	else
-		base = 0x3000;
+	if (dt_regset_xalloc_args(drp) == -1)
+		longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
 
-	idp->di_flags |= DT_IDFLG_DIFR;
-	emit(dlp, BPF_LOAD(BPF_DW, dnp->dn_reg, BPF_REG_FP, base + dnp->dn_ident->di_id));
+	emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_1, BPF_REG_FP, DT_STK_DCTX));
+	emit(dlp, BPF_MOV_IMM(BPF_REG_2, idp->di_id));
+	emit(dlp, BPF_MOV_REG(BPF_REG_3, dnp->dn_reg));
+	dt_regset_xalloc(drp, BPF_REG_0);
+	emite(dlp, BPF_CALL_FUNC(fidp->di_id), fidp);
+	dt_regset_free_args(drp);
+
+	dt_cg_check_fault(yypcb);
+
+	emit(dlp, BPF_MOV_REG(dnp->dn_reg, BPF_REG_0));
+	dt_regset_free(drp, BPF_REG_0);
 
 	/*
 	 * If this is a reference to the args[] array, we need to take the
@@ -3687,7 +3712,7 @@ dt_cg_array_op(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 	n = sizeof(uint64_t) * NBBY - size * NBBY;
 
 	emit(dlp, BPF_ALU64_IMM(BPF_LSH, dnp->dn_reg, n));
-	emit(dlp, BPF_ALU64_REG((dnp->dn_flags & DT_NF_SIGNED) ? BPF_ARSH : BPF_RSH, dnp->dn_reg, n));
+	emit(dlp, BPF_ALU64_IMM((dnp->dn_flags & DT_NF_SIGNED) ? BPF_ARSH : BPF_RSH, dnp->dn_reg, n));
 }
 
 /*

libdtrace/dt_ident.c

@@ -366,6 +366,11 @@ dt_idcook_args(dt_node_t *dnp, dt_ident_t *idp, int argc, dt_node_t *ap)
 		xyerror(D_ARGS_TYPE, "failed to resolve native type for "
 		    "%s[%lld]\n", idp->di_name, (longlong_t)ap->dn_value);
 
+	if (idp->di_type == CTF_ERR) {
+		idp->di_ctfp = DT_DYN_CTFP(dtp);
+		idp->di_type = DT_DYN_TYPE(dtp);
+	}
+
 	if (dtp->dt_xlatemode == DT_XL_STATIC && (
 	    nnp == xnp || dt_node_is_argcompat(nnp, xnp))) {
 		dnp->dn_ident = dt_ident_create(idp->di_name, idp->di_kind,

test/unittest/disasm/tst.ann-bvar.r

@@ -0,0 +1,35 @@
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg0
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg1
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg2
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg3
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg4
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg5
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg6
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg7
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg8
+85 0 1 0000 ffffffff    call dt_get_bvar              ! arg9
+85 0 1 0000 ffffffff    call dt_get_bvar              ! args
+85 0 1 0000 ffffffff    call dt_get_bvar              ! caller
+85 0 1 0000 ffffffff    call dt_get_bvar              ! curcpu
+85 0 1 0000 ffffffff    call dt_get_bvar              ! curthread
+85 0 1 0000 ffffffff    call dt_get_bvar              ! epid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! errno
+85 0 1 0000 ffffffff    call dt_get_bvar              ! execname
+85 0 1 0000 ffffffff    call dt_get_bvar              ! gid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! id
+85 0 1 0000 ffffffff    call dt_get_bvar              ! ipl
+85 0 1 0000 ffffffff    call dt_get_bvar              ! pid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! ppid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! probefunc
+85 0 1 0000 ffffffff    call dt_get_bvar              ! probemod
+85 0 1 0000 ffffffff    call dt_get_bvar              ! probename
+85 0 1 0000 ffffffff    call dt_get_bvar              ! probeprov
+85 0 1 0000 ffffffff    call dt_get_bvar              ! stackdepth
+85 0 1 0000 ffffffff    call dt_get_bvar              ! tid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! timestamp
+85 0 1 0000 ffffffff    call dt_get_bvar              ! ucaller
+85 0 1 0000 ffffffff    call dt_get_bvar              ! uid
+85 0 1 0000 ffffffff    call dt_get_bvar              ! uregs
+85 0 1 0000 ffffffff    call dt_get_bvar              ! ustackdepth
+85 0 1 0000 ffffffff    call dt_get_bvar              ! vtimestamp
+85 0 1 0000 ffffffff    call dt_get_bvar              ! walltimestamp

test/unittest/disasm/tst.ann-bvar.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+
+dtrace=$1
+
+$dtrace $dt_flags -Sen '
+sdt:task::task_rename
+{
+	trace(arg0);
+	trace(arg1);
+	trace(arg2);
+	trace(arg3);
+	trace(arg4);
+	trace(arg5);
+	trace(arg6);
+	trace(arg7);
+	trace(arg8);
+	trace(arg9);
+	trace(args[0]);
+	trace(caller);
+	trace(curcpu);
+	trace(curthread);
+	trace(epid);
+	trace(errno);
+	trace(execname);
+	trace(gid);
+	trace(id);
+	trace(ipl);
+	trace(pid);
+	trace(ppid);
+	trace(probefunc);
+	trace(probemod);
+	trace(probename);
+	trace(probeprov);
+	trace(stackdepth);
+	trace(tid);
+	trace(timestamp);
+	trace(ucaller);
+	trace(uid);
+	trace(uregs[0]);
+	trace(ustackdepth);
+	trace(vtimestamp);
+	trace(walltimestamp);
+	exit(0);
+}
+' 2>&1 | awk '/ call dt_get_bvar/ { sub(/^[^:]+: /, ""); print; }'
+
+exit $?

test/unittest/variables/bvar/err.D_ARGS_IDX.args-neg-idx.d

@@ -0,0 +1,29 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: Accessing args[-1] for probes with arguments triggers a fault.
+ *
+ * SECTION: Variables/Built-in Variables/args
+ */
+
+#pragma D option quiet
+#pragma D option destructive
+
+BEGIN
+{
+	system("echo write something > /dev/null");
+}
+
+write:entry {
+	trace(args[-1]);
+	exit(0);
+}
+
+ERROR {
+	exit(1);
+}

test/unittest/variables/bvar/err.D_ARGS_IDX.args-no-args.d

@@ -0,0 +1,23 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: Accessing args[0] for probes without arguments triggers a fault.
+ *
+ * SECTION: Variables/Built-in Variables/args
+ */
+
+#pragma D option quiet
+
+BEGIN {
+	trace(args[0]);
+	exit(0);
+}
+
+ERROR {
+	exit(1);
+}

test/unittest/variables/bvar/err.D_ARGS_IDX.args-too-many.d

@@ -0,0 +1,32 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: Accessing args[i] for probes with n arguments fails when i >= n.
+ *
+ * SECTION: Variables/Built-in Variables/args
+ */
+
+#pragma D option quiet
+#pragma D option destructive
+
+BEGIN
+{
+	system("echo write something > /dev/null");
+}
+
+write:entry {
+	trace(args[0]);
+	trace(args[1]);
+	trace(args[2]);
+	trace(args[3]);
+	exit(0);
+}
+
+ERROR {
+	exit(1);
+}

test/unittest/variables/bvar/tst.args.d → test/unittest/variables/bvar/err.D_IDENT_BADREF.args-no-idx.d

@@ -1,13 +1,12 @@
 /*
  * Oracle Linux DTrace.
- * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
  * Licensed under the Universal Permissive License v 1.0 as shown at
  * http://oss.oracle.com/licenses/upl.
  */
-/* @@xfail: dtv2 */
 
 /*
- * ASSERTION: The 'args' variable can be accessed and is not -1.
+ * ASSERTION: The 'args' variable must be indexed.
  *
  * SECTION: Variables/Built-in Variables/args
  */
@@ -16,7 +15,7 @@
 
 BEGIN {
 	trace(args);
-	exit(args != -1 ? 0 : 1);
+	exit(0);
 }
 
 ERROR {

test/unittest/variables/bvar/err.D_PROTO_ARG.args-non-scalar-idx.d

@@ -0,0 +1,23 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: The index of args[] must be a scalar.
+ *
+ * SECTION: Variables/Built-in Variables/args
+ */
+
+BEGIN
+{
+	trace(args["a"]);
+	exit(0);
+}
+
+ERROR
+{
+	exit(1);
+}

test/unittest/variables/bvar/tst.args-match-argN.d

@@ -0,0 +1,32 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the Universal Permissive License v 1.0 as shown at
+ * http://oss.oracle.com/licenses/upl.
+ */
+
+/*
+ * ASSERTION: When no argument mapping is in place, args[N] == argN, modulo
+ *	      datatype.
+ *
+ * SECTION: Variables/Built-in Variables/args
+ */
+
+#pragma D option quiet
+#pragma D option destructive
+
+BEGIN
+{
+	system("echo write something > /dev/null");
+}
+
+write:entry {
+	printf("%x vs %x\n", args[0], arg0);
+	printf("%x vs %x\n", (uint64_t)args[1], arg1);
+	printf("%x vs %x\n", args[2], arg2);
+	exit(args[0] == arg0 && (uint64_t)args[1] == arg1 && args[2] == arg2 ? 0 : 1);
+}
+
+ERROR {
+	exit(1);
+}