qbe

commit ee961fb4873891f009125fdde593a6c8e6ddd746
parent eb1df2b81e18195bcf68dd56f4f339ceda7f5365
Author: Quentin Carbonneaux <quentin.carbonneaux@yale.edu>
Date:   Wed, 22 Jul 2015 10:28:15 -0400

always preserve last build

Diffstat:
M
lisc/.gitignore
 | 
1
+
M
lisc/Makefile
 | 
3
++-

2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/lisc/.gitignore b/lisc/.gitignore
@@ -1,3 +1,4 @@
 lisc
+lisc.old
 .comfile
 *.o
diff --git a/lisc/Makefile b/lisc/Makefile
@@ -4,10 +4,11 @@ OBJ = main.o parse.o ssa.o live.o isel.o spill.o
 CFLAGS = -Wall -Wextra -std=c11 -g -pedantic
 
 $(BIN): $(OBJ)
+	mv $@ $@.old 2>/dev/null || exit 0
 	$(CC) $(LDFLAGS) $(OBJ) -o $@
 
 $(OBJ): lisc.h
 
 .PHONY: clean
 clean:
-	rm -f $(BIN) $(OBJ)
+	rm -f $(BIN) $(OBJ) *.old