Makefile: use --savable only when EMU_SNAPSHOT

Makefile

@@ -52,14 +52,22 @@ EMU_VSRC_DIR = $(abspath ./src/test/vsrc)
 EMU_CXXFILES = $(shell find $(EMU_CSRC_DIR) -name "*.cpp")
 EMU_VFILES = $(shell find $(EMU_VSRC_DIR) -name "*.v" -or -name "*.sv")
 
-EMU_CXXFLAGS  = -std=c++11 -static -Wall -I$(EMU_CSRC_DIR)
+EMU_CXXFLAGS += -std=c++11 -static -Wall -I$(EMU_CSRC_DIR)
 EMU_CXXFLAGS += -DVERILATOR -Wno-maybe-uninitialized
 EMU_LDFLAGS   = -lpthread -lSDL2 -ldl
-EMU_THREADS   = 1
-ifeq ($(EMU_THREADS), 1)
-	VTHREAD_FLAGS = --threads 1 
-else 
-	VTHREAD_FLAGS = --threads $(EMU_THREADS) --threads-dpi none
+
+# Verilator trace support
+VEXTRA_FLAGS  = --trace
+
+# Verilator multi-thread support
+EMU_THREADS  ?= 1
+VEXTRA_FLAGS += --threads $(EMU_THREADS) --threads-dpi none
+
+# Verilator savable
+EMU_SNAPSHOT ?= 0
+ifeq ($(EMU_SNAPSHOT),1)
+VEXTRA_FLAGS += --savable
+EMU_CXXFLAGS += -DVM_SAVABLE
 endif
 
 # --trace
@@ -68,10 +76,8 @@ VERILATOR_FLAGS = --top-module $(SIM_TOP) \
   +define+PRINTF_COND=1 \
   +define+RANDOMIZE_REG_INIT \
   +define+RANDOMIZE_MEM_INIT \
-  $(VTHREAD_FLAGS) \
-  --trace \
+  $(VEXTRA_FLAGS) \
   --assert \
-  --savable \
   --stats-vars \
   --output-split 5000 \
   --output-split-cfuncs 5000 \
@@ -108,7 +114,6 @@ SEED ?= $(shell shuf -i 1-10000 -n 1)
 B ?= 0
 E ?= -1
 SNAPSHOT ?=
-ENABLESNAPSHOT ?= 0
 
 # enable this runtime option if you want to generate a vcd file
 # use 'emu -h' to see more details
@@ -121,10 +126,6 @@ SNAPSHOT_OPTION = --load-snapshot=$(SNAPSHOT)
 endif
 
 
-ifeq ($(ENABLESNAPSHOT),1)
-EMU_CXXFLAGS += -D__ENABLESNAPSHOT__
-endif
-
 EMU_FLAGS = -s $(SEED) -b $(B) -e $(E) $(SNAPSHOT_OPTION) $(WAVEFORM)
 
 emu: $(EMU)

src/test/csrc/emu.cpp

@@ -107,7 +107,7 @@ Emulator::Emulator(int argc, const char *argv[]):
   enable_waveform = false;
 #endif
 
-#ifdef __ENABLESNAPSHOT__
+#ifdef VM_SAVABLE
   if (args.snapshot_path != NULL) {
     printf("loading from snapshot `%s`...\n", args.snapshot_path);
     snapshot_load(args.snapshot_path);
@@ -122,7 +122,7 @@ Emulator::Emulator(int argc, const char *argv[]):
 }
 
 Emulator::~Emulator() {
-#ifdef __ENABLESNAPSHOT__
+#ifdef VM_SAVABLE
   snapshot_slot[0].save();
   snapshot_slot[1].save();
   printf("Please remove unused snapshots manually\n");
@@ -281,7 +281,7 @@ uint64_t Emulator::execute(uint64_t n) {
       poll_event();
       lasttime_poll = t;
     }
-#ifdef __ENABLESNAPSHOT__
+#ifdef VM_SAVABLE
     static int snapshot_count = 0;
     if (trapCode != STATE_GOODTRAP && t - lasttime_snapshot > 1000 * SNAPSHOT_INTERVAL) {
       // save snapshot every 10s
@@ -314,7 +314,7 @@ inline char* Emulator::timestamp_filename(time_t t, char *buf) {
   return buf + len;
 }
 
-#ifdef __ENABLESNAPSHOT__
+#ifdef VM_SAVABLE
 inline char* Emulator::snapshot_filename(time_t t) {
   static char buf[1024];
   char *p = timestamp_filename(t, buf);
@@ -355,7 +355,7 @@ void Emulator::display_trapinfo() {
       instrCnt, cycleCnt, ipc);
 }
 
-#ifdef __ENABLESNAPSHOT__
+#ifdef VM_SAVABLE
 void Emulator::snapshot_save(const char *filename) {
   static int last_slot = 0;
   VerilatedSaveMem &stream = snapshot_slot[last_slot];