[DTrace-devel] [PATCH 2/7 v2 REVIEWED] Make dt_cg_ldsize() available to provider implementations

[Kris Van Hees]

Code generation for probe program trampolines will need dt_cg_ldsize()
(formetly known as dt_cg_load()) to generate the correct load
instructions when populating the probe argument data.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
---
 libdtrace/dt_cg.c | 34 ++++++++++++++++------------------
 libdtrace/dt_cg.h |  4 +++-
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
index 823fe8e3..50afa413 100644
--- a/libdtrace/dt_cg.c
+++ b/libdtrace/dt_cg.c
@@ -2070,15 +2070,11 @@ dt_cg_setx(dt_irlist_t *dlp, int reg, uint64_t x)
 }
 
 /*
- * Lookup the correct load opcode to use for the specified node and CTF type.
- * We determine the size and convert it to a 3-bit index.  Our lookup table
- * is constructed to use a 5-bit index, consisting of the 3-bit size 0-7, a
- * bit for the sign, and a bit for userland address.  For example, a 4-byte
- * signed load from userland would be at the following table index:
- * user=1 sign=1 size=4 => binary index 11011 = decimal index 27
+ * Lookup the correct load size modifier to use for the specified node and CTF
+ * type.
  */
-static uint_t
-dt_cg_load(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type, ssize_t *ret_size)
+uint_t
+dt_cg_ldsize(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type, ssize_t *ret_size)
 {
 #if 1
 	ctf_encoding_t e;
@@ -2413,7 +2409,7 @@ dt_cg_field_set(dt_node_t *src, dt_irlist_t *dlp,
 	 * r1 |= r2
 	 */
 	/* FIXME: Does not handle userland */
-	emit(dlp, BPF_LOAD(dt_cg_load(dst, fp, m.ctm_type, NULL), r1, dst->dn_reg, 0));
+	emit(dlp, BPF_LOAD(dt_cg_ldsize(dst, fp, m.ctm_type, NULL), r1, dst->dn_reg, 0));
 	dt_cg_setx(dlp, r2, cmask);
 	emit(dlp, BPF_ALU64_REG(BPF_AND, r1, r2));
 	dt_cg_setx(dlp, r2, fmask);
@@ -5032,16 +5028,17 @@ dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 			ssize_t	size;
 
 			/*
-			 * Save and restore DT_NF_USERLAND across dt_cg_load():
-			 * we need the sign bit from dnp and the user bit from
-			 * dnp->dn_child in order to get the proper opcode.
+			 * Save and restore DT_NF_USERLAND across
+			 * dt_cg_ldsize(): we need the sign bit from dnp and
+			 * the user bit from dnp->dn_child in order to get the
+			 * proper opcode.
 			 */
 			ubit = dnp->dn_flags & DT_NF_USERLAND;
 			dnp->dn_flags |=
 			    (dnp->dn_child->dn_flags & DT_NF_USERLAND);
 
 			dt_cg_check_notnull(dlp, drp, dnp->dn_reg);
-			op = dt_cg_load(dnp, ctfp, dnp->dn_type, &size);
+			op = dt_cg_ldsize(dnp, ctfp, dnp->dn_type, &size);
 
 			/*
 			 * If the child is an alloca pointer, bounds-check it
@@ -5205,16 +5202,17 @@ dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 			uint_t ubit;
 
 			/*
-			 * Save and restore DT_NF_USERLAND across dt_cg_load():
-			 * we need the sign bit from dnp and the user bit from
-			 * dnp->dn_left in order to get the proper opcode.
+			 * Save and restore DT_NF_USERLAND across
+			 * dt_cg_ldsize(): we need the sign bit from dnp and
+			 * the user bit from dnp->dn_left in order to get the
+			 * proper opcode.
 			 */
 			ubit = dnp->dn_flags & DT_NF_USERLAND;
 			dnp->dn_flags |=
 			    (dnp->dn_left->dn_flags & DT_NF_USERLAND);
 
 			/* FIXME: Does not handle signed and userland */
-			emit(dlp, BPF_LOAD(dt_cg_load(dnp, ctfp, m.ctm_type, NULL),
+			emit(dlp, BPF_LOAD(dt_cg_ldsize(dnp, ctfp, m.ctm_type, NULL),
 					   dnp->dn_left->dn_reg, dnp->dn_left->dn_reg, 0));
 
 			dnp->dn_flags &= ~DT_NF_USERLAND;
@@ -5326,7 +5324,7 @@ dt_cg_node(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
 
 			if (!(dnp->dn_flags & DT_NF_REF)) {
 				/* FIXME: NO signed or userland yet */
-				emit(dlp, BPF_LOAD(dt_cg_load(dnp, ctfp, dnp->dn_type, NULL),
+				emit(dlp, BPF_LOAD(dt_cg_ldsize(dnp, ctfp, dnp->dn_type, NULL),
 						   dnp->dn_reg, dnp->dn_reg, 0));
 			}
 			break;
diff --git a/libdtrace/dt_cg.h b/libdtrace/dt_cg.h
index 5752151b..ba405f34 100644
--- a/libdtrace/dt_cg.h
+++ b/libdtrace/dt_cg.h
@@ -1,6 +1,6 @@
 /*
  * Oracle Linux DTrace.
- * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 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.
  */
@@ -31,6 +31,8 @@ extern void dt_cg_tramp_return(dt_pcb_t *pcb);
 extern void dt_cg_tramp_epilogue(dt_pcb_t *pcb);
 extern void dt_cg_tramp_epilogue_advance(dt_pcb_t *pcb, dt_activity_t act);
 extern void dt_cg_tramp_error(dt_pcb_t *pcb);
+extern uint_t dt_cg_ldsize(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type,
+			 ssize_t *ret_size);
 
 #ifdef	__cplusplus
 }
-- 
2.34.1