Improve build system

ARM target works except dependency info.

Moved .gitignore from project root to build directories.
Makefile reads patterns specified in gitignore to find
all output files and remove them with the help of `find` and
`xargs`.
Do not overwrite dep info. Using `sed` to remove some dependency info.
See http://stackoverflow.com/a/9054420
and rust-lang/rust#5870.
Specified that makefiles should use bash.

arch/arm/Makefile

@@ -10,7 +10,7 @@ AS := $(GCC_PREFIX)as
 LD := $(GCC_PREFIX)ld
 
 LLC := $(LLVM_ROOT)/bin/llc
-LLCFLAGS := -march=arm -mcpu=arm926ej-s --float-abi=hard -asm-verbose
+LLCFLAGS := -mtriple=$(TARGET) -march=arm -mcpu=arm926ej-s --float-abi=hard -asm-verbose
 
 GDB := $(GCC_PREFIX)gdb
 OBJCOPY := $(GCC_PREFIX)objcopy
@@ -20,33 +20,39 @@ QEMUFLAGS := -M versatilepb -m 32M -serial stdio
 BDIR := ./boot
 CORE_LIB := ../../rust-core/core/lib.rs
 LCORE := $(BDIR)/$(shell $(RUSTC) --crate-file-name $(CORE_LIB))
+
 OBJS := $(BDIR)/loader.o $(BDIR)/aeabi_runtime.o $(BDIR)/main.o $(BDIR)/core.o
 LINK := $(BDIR)/linker.ld $(OBJS)
 
-MODS := $(wildcard */*.rs) $(wildcard ../../kernel/*.rs) $(wildcard ../../kernel/*/*.rs) $(wildcard ../../kernel/*/*/*.rs)
+# Remove dependencies of other targets. Currently not useful for one target.
+DEP_RM := arch\/
+DEP_KEEP := arch\/arm
+DEP_SCRIPT := 's/\($(DEP_KEEP)\)/\n\1/g;s/ \S*$(DEP_RM)\S*//g;s/\n\($(DEP_KEEP)\)/\1/g'
 
 -include ./config.mk
 -include $(BDIR)/core.d
--include $(BDIR)/loader.d
+-include $(BDIR)/main.d
 
 .PHONY: all run debug clean
 
 all: $(BDIR)/kernel.bin
 	@wc -c $^
 
 # Library rust-core
-$(LCORE):
-	$(RUSTC) $(RUSTCFLAGS) --dep-info $(@D)/core.d $(CORE_LIB) --emit=bc,link --out-dir $(BDIR)
+$(LCORE) $(BDIR)/core.bc:
+	$(RUSTC) $(RUSTCFLAGS) $(CORE_LIB) --dep-info --emit=bc,link --out-dir $(BDIR)
 
-# Compile rustboot
-$(BDIR)/main.bc: ../../lib.rs $(MODS) $(LCORE)
-	$(RUSTC) $(RUSTCFLAGS) --dep-info $(@D)/main.d -L $(BDIR) --emit=bc ../../lib.rs --out-dir $(BDIR)
+# Compile rustboot. Produce dependency info
+$(BDIR)/main.bc: $(LCORE)
+	$(RUSTC) $(RUSTCFLAGS) -L $(BDIR) --dep-info --emit=bc ../../lib.rs --out-dir $(BDIR)
+	@sed -i $(DEP_SCRIPT) $(BDIR)/main.d
 
 %.s: %.bc
 	$(LLC) $(LLCFLAGS) $^ -o $@
 
+# Assemble object files. note: do not overwrite deps with -MD $*.d
 %.o: %.s
-	$(AS) -MD $*.d -g $< -o $@
+	$(AS) -g $< -o $@
 
 # kernel (object)
 $(BDIR)/kernel.elf: $(LINK)
@@ -57,8 +63,8 @@ $(BDIR)/kernel.bin: $(BDIR)/kernel.elf
 	$(OBJCOPY) -O binary $^ $@
 
 # running
-run: $(BDIR)/kernel.bin
-	$(QEMU) $(QEMUFLAGS) -kernel $^
+run: all
+	$(QEMU) $(QEMUFLAGS) -kernel $(BDIR)/kernel.bin
 
 debug: $(BDIR)/kernel.elf
 ifeq ($(strip $(TMUX)),)
@@ -74,4 +80,4 @@ else
 endif
 
 clean:
-	rm -f $(BDIR)/*.{d,o,bc,rlib,so,ll,embed,elf,bin}
+	@cat $(BDIR)/.gitignore | xargs -I{} find $(BDIR) -name {} | xargs rm -f

arch/arm/boot/.gitignore

@@ -1,2 +1,11 @@
-core.s
+*.d
+
 main.s
+
+lib*.rlib
+*.bc
+
+*.elf
+*.o
+*.embed
+*.bin