Make parser reentrant

CMakeLists.txt

@@ -28,6 +28,14 @@ ExternalProject_Add(bcc
   BUILD_COMMAND ${CMAKE_COMMAND} --build . --target bcc-static
 )
 
+find_package(BISON REQUIRED)
+find_package(FLEX REQUIRED)
+bison_target(bison_parser src/parser.yy ${CMAKE_BINARY_DIR}/parser.tab.cc)
+flex_target(flex_lexer src/lexer.l ${CMAKE_BINARY_DIR}/lex.yy.cc)
+add_flex_bison_dependency(flex_lexer bison_parser)
+add_library(parser ${BISON_bison_parser_OUTPUTS} ${FLEX_flex_lexer_OUTPUTS})
+target_include_directories(parser PUBLIC src ${CMAKE_BINARY_DIR})
+
 add_subdirectory(src/arch)
 add_subdirectory(src)
 add_subdirectory(tests)

src/CMakeLists.txt

-find_package(BISON REQUIRED)
-find_package(FLEX REQUIRED)
 find_package(LLVM REQUIRED CONFIG)
 
-bison_target(parser parser.yy ${CMAKE_CURRENT_BINARY_DIR}/parser.tab.cc)
-flex_target(lexer lexer.l ${CMAKE_CURRENT_BINARY_DIR}/lex.yy.cc)
-
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
-include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 include_directories(${LLVM_INCLUDE_DIRS})
 add_definitions(${LLVM_DEFINITIONS})
 
@@ -18,17 +11,15 @@ add_executable(bpftrace
   codegen_llvm.cpp
   driver.cpp
   irbuilderbpf.cpp
-  lex.yy.cc
   main.cpp
   map.cpp
   mapkey.cpp
-  parser.tab.cc
   printer.cpp
   semantic_analyser.cpp
   types.cpp
 )
 
-target_link_libraries(bpftrace arch)
+target_link_libraries(bpftrace arch parser)
 
 llvm_map_components_to_libnames(llvm_libs bpfcodegen ipo irreader mcjit)
 target_link_libraries(bpftrace ${llvm_libs})

src/driver.cpp

@@ -3,31 +3,46 @@
 #include "driver.h"
 
 extern FILE *yyin;
-extern void *yy_scan_string(const char *yystr);
+extern void *yy_scan_string(const char *yy_str, yyscan_t yyscanner);
+extern void yyset_in(FILE *_in_str, yyscan_t yyscanner);
+extern int yylex_init(yyscan_t *scanner);
+extern int yylex_destroy (yyscan_t yyscanner);
 
 namespace bpftrace {
 
+Driver::Driver()
+{
+  yylex_init(&scanner_);
+  parser_ = std::make_unique<Parser>(*this, scanner_);
+}
+
+Driver::~Driver()
+{
+  yylex_destroy(scanner_);
+}
+
 int Driver::parse_stdin()
 {
-  return parser_.parse();
+  return parser_->parse();
 }
 
 int Driver::parse_str(const std::string &script)
 {
-  void *buffer = yy_scan_string(script.c_str());
-  int result = parser_.parse();
-  free(buffer);
+  yy_scan_string(script.c_str(), scanner_);
+  int result = parser_->parse();
   return result;
 }
 
 int Driver::parse_file(const std::string &f)
 {
-  if (!(yyin = fopen(f.c_str(), "r"))) {
+  FILE *file;
+  if (!(file = fopen(f.c_str(), "r"))) {
     std::cerr << "Error: Could not open file '" << f << "'" << std::endl;
     return -1;
   }
-  int result = parser_.parse();
-  fclose(yyin);
+  yyset_in(file, scanner_);
+  int result = parser_->parse();
+  fclose(file);
   return result;
 }
 

src/driver.h

 #pragma once
 
+#include <memory>
+
 #include "ast.h"
 #include "parser.tab.hh"
 
-#define YY_DECL bpftrace::Parser::symbol_type yylex(bpftrace::Driver &driver)
+typedef void* yyscan_t;
+#define YY_DECL bpftrace::Parser::symbol_type yylex(bpftrace::Driver &driver, yyscan_t yyscanner)
 YY_DECL;
 
 namespace bpftrace {
 
-class Driver {
+class Driver
+{
 public:
-  Driver() : parser_(*this) { }
+  Driver();
+  ~Driver();
 
   int parse_stdin();
   int parse_str(const std::string &script);
@@ -29,7 +34,8 @@ public:
   ast::Program *root_;
 
 private:
-  Parser parser_;
+  std::unique_ptr<Parser> parser_;
+  yyscan_t scanner_;
 };
 
 } // namespace bpftrace

src/lexer.l

-%option yylineno nodefault noyywrap
+%option yylineno nodefault noyywrap noinput nounput
 %option never-interactive
+%option reentrant
 %{
 #include "driver.h"
 #include "parser.tab.hh"
 
 #undef yywrap
-#define yywrap() 1
+#define yywrap(x) 1
 
 static bpftrace::location loc;
 

src/parser.yy

@@ -11,6 +11,7 @@
 %define parse.error verbose
 
 %param { bpftrace::Driver &driver }
+%param { void *yyscanner }
 %locations
 
 // Forward declarations of classes referenced in the parser

tests/CMakeLists.txt

@@ -7,18 +7,19 @@ include_directories(${CMAKE_BINARY_DIR}/src)
 
 add_executable(bpftrace_test
   main.cpp
-  #  parser.cpp
+  parser.cpp
   semantic_analyser.cpp
   ${CMAKE_SOURCE_DIR}/src/ast.cpp
   ${CMAKE_SOURCE_DIR}/src/attached_probe.cpp
   ${CMAKE_SOURCE_DIR}/src/bpftrace.cpp
+  ${CMAKE_SOURCE_DIR}/src/driver.cpp
   ${CMAKE_SOURCE_DIR}/src/map.cpp
   ${CMAKE_SOURCE_DIR}/src/mapkey.cpp
   ${CMAKE_SOURCE_DIR}/src/semantic_analyser.cpp
   ${CMAKE_SOURCE_DIR}/src/types.cpp
 )
 
-target_link_libraries(bpftrace_test arch)
+target_link_libraries(bpftrace_test arch parser)
 
 add_dependencies(bpftrace_test bcc-build)
 ExternalProject_Get_Property(bcc source_dir binary_dir)

tests/parser.cpp

 #include "gtest/gtest.h"
+#include "driver.h"
 
-TEST(test1, aaa)
+namespace bpftrace {
+
+TEST(Parser, test0)
 {
+  Driver driver;
+  std::string s = "kprobe:sys_open { @x = 1; }";
+  EXPECT_EQ(driver.parse_str(s), 0);
 }
+
+TEST(Parser, test1)
+{
+  Driver driver;
+  std::string s = "kprobe:sys_open { @x = 1; }";
+  EXPECT_EQ(driver.parse_str(s), 0);
+}
+
+} // namespace bpftrace