Add C++14 constant expression backend

Makefile

@@ -61,7 +61,7 @@ COBJS := $(addprefix out/,$(notdir $(CSRCS:.c=.o)))
 $(COBJS): out/%.o: ir/%.c
 	$(CC) -c -I. $(CFLAGS) $< -o $@
 
-ELC_SRCS := elc.c util.c rb.c py.c js.c el.c vim.c tex.c cl.c sh.c sed.c java.c c.c x86.c i.c ws.c piet.c pietasm.c bef.c bf.c unl.c
+ELC_SRCS := elc.c util.c rb.c py.c js.c el.c vim.c tex.c cl.c sh.c sed.c java.c c.c cpp.c x86.c i.c ws.c piet.c pietasm.c bef.c bf.c unl.c
 ELC_SRCS := $(addprefix target/,$(ELC_SRCS))
 COBJS := $(addprefix out/,$(notdir $(ELC_SRCS:.c=.o)))
 $(COBJS): out/%.o: target/%.c
@@ -233,6 +233,11 @@ RUNNER := tools/runc.sh
 include target.mk
 $(OUT.eir.c.out): tools/runc.sh
 
+TARGET := cpp
+RUNNER := tools/runcpp.sh
+include target.mk
+$(OUT.eir.cpp.out): tools/runcpp.sh
+
 ifeq ($(uname),Linux)
 TARGET := x86
 RUNNER :=

README.md

@@ -20,6 +20,7 @@ Currently, there are 18 backends:
 * Vim script
 * Bash
 * C
+* C++14 (compile-time)
 * i386-linux
 * C-INTERCAL
 * Whitespace

target/cpp.c

@@ -0,0 +1,173 @@
+#include <ir/ir.h>
+#include <target/util.h>
+
+size_t BUF_SIZE = 10000;
+
+static void cpp_defs(void) {
+  emit_line("#include <cstdio>");
+  emit_line("#include <utility>");
+  emit_line("");
+  emit_line("const size_t BUF_SIZE = %d;", BUF_SIZE);
+  emit_line("");
+  emit_line("constexpr char input[] =");
+  emit_line("#include \"input.txt\"");
+  emit_line(";");
+  emit_line("");
+  emit_line("struct buffer {");
+  emit_line(" unsigned int size;");
+  emit_line(" unsigned int b[BUF_SIZE];");
+  emit_line("};");
+  emit_line("template <size_t... I>");
+  emit_line("constexpr buffer make_buf_impl(unsigned int size, unsigned int* buf, std::index_sequence<I...>) {");
+  emit_line(" return buffer{size, {buf[I]...}};");
+  emit_line("}");
+  emit_line("constexpr buffer make_buf(unsigned int size, unsigned int* buf) {");
+  emit_line(" return make_buf_impl(size, buf, std::make_index_sequence<BUF_SIZE>{});");
+  emit_line("}");
+}
+
+static void cpp_init_state(Data* data) {
+  for (int i = 0; i < 7; i++) {
+    emit_line("unsigned int %s = 0;", reg_names[i]);
+  }
+
+  emit_line("unsigned int i_cur = 0;");
+  emit_line("unsigned int o_cur = 0;");
+  emit_line("unsigned int mem[1<<24] = {0};");
+  emit_line("unsigned int buf[BUF_SIZE] = {0};");
+
+  for (int mp = 0; data; data = data->next, mp++) {
+    if (data->v) {
+      emit_line("mem[%d] = %d;", mp, data->v);
+    }
+  }
+}
+
+static void cpp_emit_prologue(void) {
+  emit_line("");
+  emit_line("while (1) {");
+  inc_indent();
+  emit_line("switch (pc) {");
+  emit_line("case 0:");
+  inc_indent();
+}
+
+static void cpp_emit_epilogue(void) {
+  dec_indent();
+  emit_line("}");
+  emit_line("pc++;");
+  dec_indent();
+  emit_line("}");
+  emit_line("return make_buf(o_cur, buf);");
+  dec_indent();
+  emit_line("}");
+}
+
+static void cpp_emit_pc_change(int pc) {
+  emit_line("break;");
+  emit_line("");
+  dec_indent();
+  emit_line("case %d:", pc);
+  inc_indent();
+}
+
+static void cpp_emit_inst(Inst* inst) {
+  switch (inst->op) {
+  case MOV:
+    emit_line("%s = %s;", reg_names[inst->dst.reg], src_str(inst));
+    break;
+
+  case ADD:
+    emit_line("%s = (%s + %s) & " UINT_MAX_STR ";",
+              reg_names[inst->dst.reg],
+              reg_names[inst->dst.reg], src_str(inst));
+    break;
+
+  case SUB:
+    emit_line("%s = (%s - %s) & " UINT_MAX_STR ";",
+              reg_names[inst->dst.reg],
+              reg_names[inst->dst.reg], src_str(inst));
+    break;
+
+  case LOAD:
+    emit_line("%s = mem[%s];", reg_names[inst->dst.reg], src_str(inst));
+    break;
+
+  case STORE:
+    emit_line("mem[%s] = %s;", src_str(inst), reg_names[inst->dst.reg]);
+    break;
+
+  case PUTC:
+    emit_line("buf[o_cur++] = %s;", src_str(inst));
+    break;
+
+  case GETC:
+    emit_line("%s = (input[i_cur] ? input[i_cur++] : 0);",
+              reg_names[inst->dst.reg]);
+    break;
+
+  case EXIT:
+    emit_line("return make_buf(o_cur, buf);");
+    break;
+
+  case DUMP:
+    break;
+
+  case EQ:
+  case NE:
+  case LT:
+  case GT:
+  case LE:
+  case GE:
+    emit_line("%s = %s;",
+              reg_names[inst->dst.reg], cmp_str(inst, "1"));
+    break;
+
+  case JEQ:
+  case JNE:
+  case JLT:
+  case JGT:
+  case JLE:
+  case JGE:
+  case JMP:
+    emit_line("if (%s) pc = %s - 1;",
+              cmp_str(inst, "1"), value_str(&inst->jmp));
+    break;
+
+  default:
+    error("oops");
+  }
+}
+
+void cpp_emit_main_loop(Inst* inst) {
+  int prev_pc = 0;
+  for (; inst; inst = inst->next) {
+    if (prev_pc != inst->pc) {
+      cpp_emit_pc_change(inst->pc);
+    }
+    prev_pc = inst->pc;
+    cpp_emit_inst(inst);
+  }
+}
+
+void target_cpp(Module* module) {
+  cpp_defs();
+  emit_line("");
+  emit_line("constexpr buffer constexpr_main() {");
+  inc_indent();
+
+  cpp_init_state(module->data);
+  cpp_emit_prologue();
+  cpp_emit_main_loop(module->text);
+  cpp_emit_epilogue();
+
+  emit_line("");
+  emit_line("int main() {");
+  emit_line(" constexpr buffer buf = constexpr_main();");
+  emit_line(" constexpr unsigned int output_size = buf.size;");
+  emit_line("");
+  emit_line(" for(int i = 0; i < output_size; ++i) {");
+  emit_line("  putchar(buf.b[i]);");
+  emit_line(" }");
+  emit_line("}");
+}

target/elc.c

@@ -16,6 +16,7 @@ void target_sh(Module* module);
 void target_sed(Module* module);
 void target_java(Module* module);
 void target_c(Module* module);
+void target_cpp(Module* module);
 void target_x86(Module* module);
 void target_i(Module* module);
 void target_ws(Module* module);
@@ -49,6 +50,8 @@ static target_func_t get_target_func(const char* ext) {
     return target_java;
   } else if (!strcmp(ext, "c")) {
     return target_c;
+  } else if (!strcmp(ext, "cpp")) {
+    return target_cpp;
   } else if (!strcmp(ext, "x86")) {
     return target_x86;
   } else if (!strcmp(ext, "i")) {

tools/runcpp.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+set -e
+
+dir=$(mktemp -d)
+mkdir -p $dir
+cp $1 $dir
+infile=${dir}/input.txt
+
+cat > $infile
+
+if [ ! -s $infile ]; then
+    echo '""' > $infile
+else
+  sed -i '1s/^/R"(/' $infile
+  echo ')"' >> $infile
+fi
+
+g++-6 ${dir}/$(basename $1) -o $1.exe
+rm -fr $dir
+./$1.exe