use less temporaries

bootstrap/emit.cc

@@ -3,6 +3,11 @@
 
 namespace xlang {
 
+std::string EmitVisitor::tmp() {
+  last = "%t" + std::to_string(tmpcount++);
+  return last;
+}
+
 EmitVisitor::EmitVisitor(std::string_view outputfile) : output{outputfile} {}
 
 std::any EmitVisitor::visitFile(xlangParser::FileContext *ctx) {
@@ -32,8 +37,8 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   if (auto identifier = ctx->Identifier()) {
     tmpcount = 0;
     visitExpr(ctx->expr());
-    output << "  %_" << identifier->getSymbol()->getText() << " = w copy %t"
+    output << "  %_" << identifier->getSymbol()->getText() << " = w copy "
-           << tmpcount - 1 << std::endl;
+           << last << std::endl;
     return {};
   }
   if (ctx->If()) {
@@ -41,8 +46,8 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
     output << "@if" << block << "_expr" << std::endl;
     tmpcount = 0;
     visitExpr(ctx->expr());
-    output << "  jnz %t" << tmpcount - 1 << ", @if" << block << "_then, @if"
+    output << "  jnz " << last << ", @if" << block << "_then, @if" << block
-           << block << "_else" << std::endl;
+           << "_else" << std::endl;
     output << "@if" << block << "_then" << std::endl;
     visitBlock(ctx->block(0));
     output << "  jmp @if" << block << "_end" << std::endl;
@@ -58,8 +63,8 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
     output << "@while" << block << "_expr" << std::endl;
     tmpcount = 0;
     visitExpr(ctx->expr());
-    output << "  jnz %t" << tmpcount - 1 << ", @while" << block
+    output << "  jnz " << last << ", @while" << block << "_body, @while"
-           << "_body, @while" << block << "_end" << std::endl;
+           << block << "_end" << std::endl;
     output << "@while" << block << "_body" << std::endl;
     visitBlock(ctx->block(0));
     output << "  jmp @while" << block << "_expr" << std::endl;
@@ -69,14 +74,14 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   if (ctx->Return()) {
     tmpcount = 0;
     visitExpr(ctx->expr());
-    output << "  ret %t" << tmpcount - 1 << std::endl;
+    output << "  ret " << last << std::endl;
     output << "@dead" << blockcount++ << std::endl;
     return {};
   }
   if (ctx->Print()) {
     tmpcount = 0;
     visitExpr(ctx->expr());
-    output << "  call $printf(l $printformat, ..., w %t" << tmpcount - 1 << ")"
+    output << "  call $printf(l $printformat, ..., w " << last << ")"
            << std::endl;
     return {};
   }
@@ -87,11 +92,11 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
 #define OPERATOR(Operator, visitLeft, left, visitRight, right, ssa_op) \
   if (ctx->Operator()) {                                               \
     visitLeft(ctx->left);                                              \
-    int l = tmpcount - 1;                                               \
+    std::string l = last;                                              \
     visitRight(ctx->right);                                            \
-    output << "  %t" << tmpcount << " = w " ssa_op " %t" << l << ", %t" \
+    std::string r = last;                                              \
-           << tmpcount - 1 << std::endl;                                \
+    output << "  " << tmp() << " = w " ssa_op " " << l << ", " << r    \
-    tmpcount++;                                                         \
+           << std::endl;                                               \
     return {};                                                         \
   }
 
@@ -122,28 +127,26 @@ std::any EmitVisitor::visitTerm(xlangParser::TermContext *ctx) {
 
 std::any EmitVisitor::visitFactor(xlangParser::FactorContext *ctx) {
   if (auto integer = ctx->Integer()) {
-    output << "  %t" << tmpcount++ << " = w copy "
+    last = integer->getSymbol()->getText();
-           << integer->getSymbol()->getText() << std::endl;
     return {};
   }
   if (auto identifier = ctx->Identifier()) {
     if (ctx->LeftParen()) {
-      std::vector<int> args;
+      std::vector<std::string> args;
       if (auto expr_list = ctx->exprList()) {
         for (auto expr : expr_list->expr()) {
           visitExpr(expr);
-          args.push_back(tmpcount - 1);
+          args.push_back(last);
         }
       }
-      output << "  %t" << tmpcount++ << " = w call $"
+      output << "  " << tmp() << " = w call $"
              << identifier->getSymbol()->getText() << "(";
       for (auto arg : args) {
-        output << "w %t" << arg << ", ";
+        output << "w " << arg << ", ";
       }
       output << ")" << std::endl;
     } else {
-      output << "  %t" << tmpcount++ << " = w copy %_"
+      last = "%_" + identifier->getSymbol()->getText();
-             << identifier->getSymbol()->getText() << std::endl;
     }
     return {};
   }

bootstrap/emit.hh

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <fstream>
+#include <string>
 #include <string_view>
 #include <xlangBaseVisitor.h>
 
@@ -10,6 +11,9 @@ class EmitVisitor : public xlangBaseVisitor {
   std::ofstream output;
   int blockcount;
   int tmpcount;
+  std::string last;
+
+  std::string tmp();
 
  public:
   EmitVisitor(std::string_view outputfile);