Facebookhip?phpvm cash overview (2)

Facebookhipmo-phpvm implementation overview (2) from the above, we can see that the core runtime environment code is in src/runtme/eval. This article mainly gives a brief overview of the code implementation here. the following descriptions are classified by folders. 1. runtime: core data structure (symbol table) during runtime 1. assoc_list.cpp & nb facebook hiphop php vm implementation overview (2)
We can see from the above that the code of the core runtime environment is in src/runtme/eval. This article mainly briefly describes the code implementation here, and the following description is classified by folder.

1. runtime: core data structure during running (symbol table)
1. assoc_list.cpp variable Association table
2. code_coverage.cpp Code Coverage Tool
3. jit cache of file_repository.cpp php file
4. variable_environment.cpp maintains the environment (such as the class and scope) of each function and variable)
5. variant_stack.cpp variable stack structure (can be used to record the function call relationship)

6. the most important runtime information of eval_state.cpp is collected here, such as the current objects, the methods, global functions, and constants of each object ......
7. eval_object_data.h records the information of a class.
8. a stack frame in the eval_frame_injection.h function call

II. ext
This directory encapsulates methods for adding external functions to the runtime,

III. parser
Parser implemented by YACC (the EBNF syntax file is hphp. y, hphp. tab. cpp is generated by a tool). This parser is different from the compiler directory. here it mainly serves semantic parsing (which can be understood as TreeWalker ). For hiphop php vm, semantic processing is to map php code to c ++ code (a large number of external functions are required for runtime ).

1. Overview of hphp. y
Grammar start symbol: start
Processing of file inclusion relationships and statement addition in src/runtime/eval/parser. cpp, the output of onXXX () is an AST, and the top node is statement.

4. debugger uses the socket-implemented debugger
Finally, the real start is void DebuggerProxy: processInterrupt (required interrupt & cmd)

V. base
Basic data structure statement

VI. ast
Perform semantic processing on the AST parsed by parser (that is, convert php code to c ++ code for each layer of tree node)
The unified interface for each statement is
Virtual Statement * optimize (VariableEnvironment & env) {return NULL;} // optimization Statement
Virtual void eval (VariableEnvironment & env) const = 0; // process the statement relationship
Virtual void byteCode (ByteCodeProgram & code) const ;//
Dump (std: ostream & out) const = 0; // Output c ++ code

PS:
Eval: The Inheritance structure developed by Construct is beautifully written.
VII. Scope of analysis

8. runtime semantic processing is the main process for translating php to c ++.
Eval. cpp Variant eval (LVariableTable * vars, CObjRef self, CStrRef code_str, bool prepend_php/* = true */)

1. php source code preprocessing
2. ParseString () tree traversal
3. s-> eval (env); semantic analysis (recursive)

9. implementation of function calls
Basic idea of function calling: Find the execution environment information such as object, method, and variable based on the symbol table information, and create a thread stack frame each time a function is entered, convert php function calls to the execution logic of external functions