Added initial implementation of synthetic encoding/decoding.

core/CMakeLists.txt

@@ -280,6 +280,7 @@ set(DECODER_SRCS
   ir/encode_shared.c
   ir/${ARCH_NAME}/encode.c
   ir/synthetic/encode.c
+  ir/synthetic/decode.c
   ir/disassemble_shared.c
   ir/${ARCH_NAME}/disassemble.c
   ir/ir_utils_shared.c
@@ -1213,7 +1214,6 @@ DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/arm/opcode_api.h dr_ir_opcodes_a
 DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/instr_create_shared_api.h dr_ir_macros.h)
 DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/x86/instr_create_api.h dr_ir_macros_x86.h)
 DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/arm/instr_create_api.h dr_ir_macros_arm.h)
-DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/synthetic/encode.h dr_ir_encode_synthetic.h)
 DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/ir/aarch64/instr_create_api.h
   dr_ir_macros_aarch64.h)
 DR_export_header(${CMAKE_CURRENT_SOURCE_DIR}/lib/dr_ir_utils.h dr_ir_utils.h)

core/ir/synthetic/decode.c

@@ -0,0 +1,93 @@
+/* **********************************************************
+ * Copyright (c) 2011-2024 Google, Inc.  All rights reserved.
+ * Copyright (c) 2001-2010 VMware, Inc.  All rights reserved.
+ * **********************************************************/
+
+/*
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of VMware, Inc. nor the names of its contributors may be
+ *   used to endorse or promote products derived from this software without
+ *   specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL VMWARE, INC. OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ */
+/* Copyright (c) 2003-2007 Determina Corp. */
+/* Copyright (c) 2001-2003 Massachusetts Institute of Technology */
+/* Copyright (c) 2001 Hewlett-Packard Company */
+
+/* decode.c -- a decoder for DR synthetic IR */
+
+#include "encode.h"
+#include "decode.h"
+
+#include "../globals.h"
+#include "instr_api.h"
+
+#define CATEGORY_BITS 22
+#define FLAGS_BITS 2
+#define NUM_OPND_BITS 4
+
+void
+decode_from_synth(dcontext_t *dcontext, byte *encoded_instr, instr_t *instr)
+{
+    uint encoding = 0;
+    uint shift = 0;
+
+    /*
+     * Copy encoded_instr in a uint for easy retrieving of values.
+     */
+    memcpy(&encoding, encoded_instr, sizeof(uint));
+
+    /*
+     * Decode synthetic opcode as instruction category.
+     */
+    uint category_mask = (1U << CATEGORY_BITS) - 1;
+    uint category = encoding & category_mask;
+    instr_set_category(instr, category);
+    shift += CATEGORY_BITS;
+
+    /*
+     * Decode flags.
+     */
+    // Commented to avoid unused variable error.
+    // uint flags_mask = ((1U << FLAGS_BITS) - 1) << shift;
+    // uint flags = encoding & flags_mask;
+    // TOFIX: set all arithmetic flags of instr_t?
+    shift += FLAGS_BITS;
+
+    /*
+     * Decode number of source operands.
+     */
+    uint num_srcs_mask = ((1U << NUM_OPND_BITS) - 1) << shift;
+    uint num_srcs = encoding & num_srcs_mask;
+    shift += NUM_OPND_BITS;
+
+    /*
+     * Decode number of destination operands.
+     */
+    uint num_dsts_mask = ((1U << NUM_OPND_BITS) - 1) << shift;
+    uint num_dsts = encoding & num_dsts_mask;
+
+    instr_set_num_opnds(dcontext, instr, num_dsts, num_srcs);
+
+    return;
+}

core/ir/synthetic/decode.h

@@ -0,0 +1,9 @@
+#ifndef _SYNTHETIC_DECODE_H_
+#define _SYNTHETIC_DECODE_H_ 1
+
+#include "../globals.h"
+
+void
+decode_from_synth(dcontext_t *dcontext, byte *encoded_instr, instr_t *instr);
+
+#endif /* _SYNTHETIC_DECODE_H_ */

core/ir/synthetic/encode.c

@@ -40,11 +40,52 @@
 
 #include "../globals.h"
 
+#define CATEGORY_BITS 22
+#define FLAGS_BITS 2
+#define NUM_OPND_BITS 4
+
 void
 encode_to_synth(dcontext_t *dcontext, instr_t *instr, byte *encoded_instr)
 {
+    uint encoding = 0;
+    uint shift = 0;
+
+    /*
+     * Encode category as synthetic opcode.
+     */
     uint category = instr_get_category(instr);
-    memcpy(encoded_instr, &category, sizeof(uint));
+    encoding |= category;
+    shift += CATEGORY_BITS;
+
+    /*
+     * Encode flags.
+     */
+    // TOFIX: this is probably not the right way to look at arithmetic flags of an instr_t
+    uint flags = (uint)instr_arith_flags_valid(instr);
+    encoding |= (flags << shift);
+    shift += FLAGS_BITS;
+
+    /*
+     * Encode number of source operands.
+     */
+    uint num_srcs = (uint)instr_num_srcs(instr);
+    encoding |= (num_srcs << shift);
+    shift += NUM_OPND_BITS;
+
+    /*
+     * Encode number of destination operands.
+     */
+    uint num_dsts = (uint)instr_num_dsts(instr);
+    encoding |= (num_dsts << shift);
+
+    /*
+     * TODO: Encode registers.
+     */
+
+    /*
+     * Copy result to output encoded_instr.
+     */
+    memcpy(encoded_instr, &encoding, sizeof(uint));
 
     return;
 }