support negative integers

src/ast/ast.cpp

@@ -106,6 +106,7 @@ std::string opstr(Unop &unop)
   switch (unop.op) {
     case bpftrace::Parser::token::LNOT: return "!";
     case bpftrace::Parser::token::BNOT: return "~";
+    case bpftrace::Parser::token::MINUS: return "-";
     case bpftrace::Parser::token::MUL:  return "dereference";
     default: abort();
   }

src/ast/codegen_llvm.cpp

@@ -625,6 +625,7 @@ void CodegenLLVM::visit(Unop &unop)
     switch (unop.op) {
       case bpftrace::Parser::token::LNOT: expr_ = b_.CreateNot(expr_); break;
       case bpftrace::Parser::token::BNOT: expr_ = b_.CreateNeg(expr_); break;
+      case bpftrace::Parser::token::MINUS: expr_ = b_.CreateNeg(expr_); break;
       case bpftrace::Parser::token::MUL:
       {
         int size = type.size;

src/lexer.l

@@ -53,7 +53,7 @@ pid|tid|uid|gid|nsecs|cpu|comm|stack|ustack|arg[0-9]|retval|func|name|curtask|ra
 {path}                  { return Parser::make_PATH(yytext, loc); }
 {map}                   { return Parser::make_MAP(yytext, loc); }
 {var}                   { return Parser::make_VAR(yytext, loc); }
-{int}                   { return Parser::make_INT(strtoul(yytext, NULL, 0), loc); }
+{int}                   { return Parser::make_INT(strtoll(yytext, NULL, 0), loc); }
 ":"                     { return Parser::make_COLON(loc); }
 ";"                     { return Parser::make_SEMI(loc); }
 "{"                     { return Parser::make_LBRACE(loc); }

src/parser.yy

@@ -198,6 +198,7 @@ expr : INT             { $$ = new ast::Integer($1); }
      | expr BXOR expr  { $$ = new ast::Binop($1, token::BXOR,  $3); }
      | LNOT expr       { $$ = new ast::Unop(token::LNOT, $2); }
      | BNOT expr       { $$ = new ast::Unop(token::BNOT, $2); }
+     | MINUS expr       { $$ = new ast::Unop(token::MINUS, $2); }
      | MUL  expr %prec DEREF { $$ = new ast::Unop(token::MUL,  $2); }
      | expr DOT ident  { $$ = new ast::FieldAccess($1, $3); }
      | expr PTR ident  { $$ = new ast::FieldAccess(new ast::Unop(token::MUL, $1), $3); }

tests/parser.cpp

@@ -125,6 +125,13 @@ TEST(Parser, variable_assign)
       "  =\n"
       "   variable: $x\n"
       "   int: 1\n");
+  test("kprobe:sys_open { $x = -1; }",
+      "Program\n"
+      " kprobe:sys_open\n"
+      "  =\n"
+      "   variable: $x\n"
+      "   -\n"
+      "    int: 1\n");
 }
 
 TEST(Parser, integer_sizes)