i#4915: label non-fetched instructions in drmemtrace view tool (#7810)

Instruction records with type TRACE_TYPE_INSTR_NO_FETCH were previously
displayed as normal ifetch entries in the drmemtrace view tool when
decoding was enabled, which was misleading for REP string expansion.

This change updates the view tool output to label such records as
non-fetched, without altering trace generation or expansion logic.

Xref #4915.

Author: GandholiSarat

clients/drcachesim/tests/view_test.cpp

@@ -803,6 +803,40 @@ run_chunk_tests(void *drcontext)
     return run_single_thread_chunk_test(drcontext) && run_serial_chunk_test(drcontext);
 }
 
+#ifdef X86
+bool
+run_unfetched_rep_string_test(void *drcontext)
+{
+    static constexpr addr_t BASE_ADDR = 0x123450;
+    const memref_tid_t tid = 1;
+    const uint64_t filetype = OFFLINE_FILE_TYPE_ENCODINGS;
+
+    instrlist_t *ilist = instrlist_create(drcontext);
+    instr_t *rep_movs = INSTR_CREATE_rep_movs_1(drcontext);
+    instrlist_append(ilist, rep_movs);
+
+    std::vector<memref_with_IR_t> memref_setup = {
+        { gen_marker(tid, TRACE_MARKER_TYPE_FILETYPE, static_cast<uintptr_t>(filetype)),
+          nullptr },
+        { gen_instr_type(TRACE_TYPE_INSTR, tid), rep_movs },
+        { gen_instr_type(TRACE_TYPE_INSTR_NO_FETCH, tid), nullptr },
+    };
+    std::vector<memref_t> memrefs =
+        add_encodings_to_memrefs(ilist, memref_setup, BASE_ADDR);
+
+    view_test_t view(drcontext, *ilist);
+    std::string res = run_test_helper(view, memrefs);
+    instrlist_clear_and_destroy(drcontext, ilist);
+
+    if (res.find("non-fetched") == std::string::npos) {
+        std::cerr << "Missing non-fetched label for rep string unfetched record\n";
+        std::cerr << "Output was: " << res << "\n";
+        return false;
+    }
+    return true;
+}
+#endif
+
 /* Test view tool on a OFFLINE_FILE_TYPE_ARCH_REGDEPS trace.
  * The trace hardcoded in entries is X64, so we only test on X64 architectures here.
  */
@@ -883,6 +917,9 @@ test_main(int argc, const char *argv[])
 {
     void *drcontext = dr_standalone_init();
     if (run_limit_tests(drcontext) && run_chunk_tests(drcontext) &&
+#ifdef X86
+        run_unfetched_rep_string_test(drcontext) &&
+#endif
         run_regdeps_test(drcontext)) {
         std::cerr << "view_test passed\n";
         return 0;

clients/drcachesim/tools/view.cpp

@@ -527,7 +527,9 @@ view_t::parallel_shard_memref(void *shard_data, const memref_t &memref)
     if (trace_version_ == -1) {
         trace_version_ = static_cast<int>(serial_stream_->get_version());
     }
-    std::cerr << std::left << std::setw(name_width) << "ifetch" << std::right
+    const char *instr_name =
+        (memref.instr.type == TRACE_TYPE_INSTR_NO_FETCH ? "non-fetched" : "ifetch");
+    std::cerr << std::left << std::setw(name_width) << instr_name << std::right
               << std::setw(2) << memref.instr.size << " byte(s) @ 0x" << std::hex
               << std::setfill('0') << std::setw(sizeof(void *) * 2) << memref.instr.addr
               << std::dec << std::setfill(' ');