If the optimiser does such a reordering it is still bound to the C specification, so such a reordering would become: uint64_t u64_z = (uint64_t)u32_x + (uint64_t)u32_y + u64_a; Rationale: We start with uint64_t u64_z = u32_x + u64_a + u32_y; Addition is performed left-to-right. The integer promotion rules state that in the first addition … Read more
SLR, LALR and LR parsers can all be implemented using exactly the same table-driven machinery. Fundamentally, the parsing algorithm collects the next input token T, and consults the current state S (and associated lookahead, GOTO, and reduction tables) to decide what to do: SHIFT: If the current table says to SHIFT on the token T, … Read more
Using “Compilers Principles, Techniques, & Tools, 2nd Ed.” (WorldCat) by Aho, Lam, Sethi and Ullman, AKA the Purple Dragon Book, Lexeme pg. 111 A lexeme is a sequence of characters in the source program that matches the pattern for a token and is identified by the lexical analyzer as an instance of that token. Token … Read more
It’s an annotation, but the correct name is NonNull: protected void onSaveInstanceState(@NonNull Bundle outState) (And also) import android.support.annotation.NonNull; The purpose is to allow the compiler to warn when certain assumptions are being violated (such as a parameter of a method that should always have a value, as in this particular case, although there are others). … Read more
=====> COMPILATION PROCESS <====== | |—-> Input is Source file(.c) | V +=================+ | | | C Preprocessor | | | +=================+ | | —> Pure C file ( comd:cc -E <file.name> ) | V +=================+ | | | Lexical Analyzer| | | +—————–+ | | | Syntax Analyzer | | | +—————–+ | | … Read more
These are undocumented implementation details of the compiler, and subject to change at any time. (UPDATE: See GeneratedNames.cs in the C# sources for the current details; the description below is somewhat out-of-date.) However, since I’m a nice guy, here are some of those details: If you have an unused local variable that the optimizer removes, … Read more
This is based on the Expression Evaluator grammar by Terrence Parr. The grammar for this example: grammar Expr002; options { output=AST; ASTLabelType=CommonTree; // type of $stat.tree ref etc… } prog : ( stat )+ ; stat : expr NEWLINE -> expr | ID ‘=’ expr NEWLINE -> ^(‘=’ ID expr) | NEWLINE -> ; expr … Read more
Create a .o file: g++ -c header.cpp add this file to a library, creating library if necessary: ar rvs header.a header.o use library: g++ main.cpp header.a
You should install package “libgl1-mesa-dev”: sudo apt install libgl1-mesa-dev
Updated Now with improved recursion depth! Works on MSVC10 and GCC without increased depth. 🙂 Simple compile-time recursion + addition: template<unsigned Cur, unsigned Goal> struct adder{ static unsigned const sub_goal = (Cur + Goal) / 2; static unsigned const tmp = adder<Cur, sub_goal>::value; static unsigned const value = tmp + adder<sub_goal+1, Goal>::value; }; template<unsigned Goal> … Read more