Questions tagged [compiler]
A compiler is a computer program that transforms source code written in one programming language into another computer language.
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Generalised indexing scheme for variable memory layouts
structs are great, the only problem is that not only do they associate data (topo)logically, they also crystallise a memory layout for that set of concepts. I would like to avoid the latter.
So I'm ...
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How modern runtimes handle both interpreted and JITted code at the same time?
I have a personal project, I want to write a JIT compiler/runtime in Rust (well, the language is not that relevant). I'm thinking about using a technique where the code is interpreted first and then ...
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why languages need an import/include/using etc to refer to other code in other files?
In various languages I came across during my career require some import/using/include etc. to refer to the code in other file.
while the same languages also require a package manager or a list of ...
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Concatenating strings given a BNF grammar
<Definition> ::= <Name> <LeftPar> <param> <RightPar>
<Name> ::= <Letter><LetterTail>
<LetterTail> ::= <Letter><LetterTail> | ‘’
A ...
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Is it possible to build a semantically unambigous grammar / language / graph?
It's been a long time that I had an idea of a semantic constraint as compiler optimizations which allows for sophisticated high level optimization allowing you to transform the AST/CFG based on a SFG (...
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Implementing a memory efficient Abstract Syntax Tree
I am writing a compiler in C++ 20. I am looking for ways to improve heap memory performance. For example, I can compile a 36.8 MB source file that is just many repeating lines of:
let x0: string = &...
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Is there any logical reason to "store" just one object file (.o) into archival file (.a)?
As far as I understand (not much), the archival .a file is just, roughly speaking, the collection/batch of object .o files. It's like a library of compiled code that can be cached and which can be ...
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How to approach converting to and from kafka messages?
I would like to have a series of small stand-alone services that would either consume a Kafka topic and output the data into a different system or the reverse: receive data from a system and produce ...
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Why is it necessary to mark classes as not inherited from? Can't an optimizer automatically detect that virtual calls are unnecessary?
In C# and C++, an apparent trend is in place to reduce / avoid inheritance:
C#: "Sealing types can improve performance."
https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/...
user417068
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How do function inlining and Tail Call Optimization affect call stack?
I've just accidentally came across this answer about inlined functions and I'd like to know how this affects call stack. But I can't add comments because I don't have enough rep so I decided to ask ...
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How can I represent a transformed AST between compilation stages?
I'm writing a compiler in Rust. I've reached the point where I have an AST and am ready to do symbol resolution, type-checking, etc. But, I'm unsure of how to represent an AST as containing "...
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What lessons can be learned from the architecture/combination of ESLint and Prettier for linting and code formatting?
I was looking through the prettier docs and the prettier source code. It essentially has those defined helper functions to layout the text, given an AST. It operates on the level of the whole file, on ...
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Implementing heap-allocated closures in LLVM
I'm writing my own F#-esque language and I'm using LLVM for code generation. I want my language to support continuation passing style and I think I've got TCO figured out but I cannot figure out how ...
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Modular Design affects compilation time
Does modular design decrease compilation time in cpp? My professor said so, but I don't understand how, because the build and compilation time depend on the amount of code, right?
Also, wouldn't ...
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why do we need instructions set for processor or controller?
Why is it necessary to have an instruction set for processors and controllers? Can't we simply convert high-level language programs, like those written in C, directly into binaries without the need ...
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Debugging miscompile [closed]
Recently I encountered an issue at work where a unit test written in C++ would crash only when being compiled with MSVC 2017 (MSVC 2019 and up are fine). I tried to debug this issue and it seems like ...
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Is it true that variable type before name makes compiler work easier? [closed]
I have seen information that at least one of reasons why type placed before variable name is that it allows compiler easier evaluate size and type of variable. If so then how (what way) it eases this ...
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When writing a tokenizer, what is the standard practice for handling aliased language keywords?
When writing a tokenizer, what is the standard practice for handling aliased language keywords?
For example, notethat signed short int is a language keyword in C++ and several aliases might be allowed....
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Custom #pragma directives
I'm creating a language parser on a microprocessor in C++. For the tables of keywords and commands, rather than maintaining a single curated file (alphabetically sorted, etc), I'd prefer to declare ...
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Are indirect implicit type declerations dangerous?
In the case of kotlin, rust and many other programming languages...
There are variables with direct implicit type declarations...
Where you can see the type of a variable at the same line where it's ...
user426780
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Better way to represent grammar symbols in C
I'm trying to build a simple compiler for a subset of the C language in C. To achieve this, I needed to figure out a way to represent the grammar symbols. Basically, each symbol can either be a "...
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How to propagate lexical scope in a compiler, specifically around step-by-step functions?
I am working on a compiler in TypeScript, and currently am focused on how to pass around the "lexical scope" to the relevant objects. Essentially every time there is a conceptual major ...
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How do compilers work in a language that doesn't allow recursion?
I'm recently learning the programming language, and I wonder how compilers work when the language itself does not allow recursion, like how the compiler or the runtime checkers makes sure that there ...
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How does a JIT compiler actually emit and then call the emitted native code?
Assuming that a VM runs a JIT compiler on otherwise "interpreted" code, such as a line by line interpreter or some form of bytecode/IL code and determines that it can create optimised native ...
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Why is Java AOT compilation (using graalvm native-image) so much slower than golang compilation?
I followed the guide here https://quarkus.io/guides/building-native-image to set up a minimal quarkus webservice graalvm native image. Ran command 'time quarkus build --native' to compile the example. ...
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Can we reliably use unaligned scalars on contemporary hardware?
Processors have come a long way in their handling of unaligned data - from crashing at the very notion of it, through suffering severe penalties, all the way to having almost no impact.
I suppose it ...
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Java: Is there a performance difference between variable assignment vs. inline usage?
Is there any performance detriment to assigning variables vs using them inline. I'm guessing this WOULD be worse if a method was returning primitive and I was 'boxing' it (e.g. method returning int, ...
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How to Validate Output Binary During/After Compilation on Platform without ECC Memory [closed]
On a platform with ECC memory, you can assure the compiled binary is 100% legit with EDAC daemon. (single-bit error will be corrected automatically, and multi-bit error will be logged so you can just ...
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How to manage concurrent build & test toolchains in (embedded) software development?
TL;DR: How do you manage the complex development toolchain in different (embedded) projects?
In our company we are discussing the toolchain setups in different development teams and how to work ...
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Parsing complex data type names
How do compilers parse complex data types names like function pointers. The type has to be somehow put into the AST or it has to be processed during parsing. What are the pros and cons of different ...
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When making a compiler, what's the best way for compiling to machine code in the backend? [closed]
I know that a lot of compilers use an assembler to compile to machine code, to make an executable (compiled program).
Some people even made their own assemblers, or they just use an existing assembler,...
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Isn't OS dependent on machines, can anyone briefly explain how it is achieved? [closed]
Certain OS in it's system requirement doesn't specify anything peculiar like in case of ubuntu it asks only for "2 GHz dual core processor or better". If yes, how does it compares with ...
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How to deal with forward references in a compiler?
I'm creating a very simple compiler PoC that only has
Procedures
Calls to procedures.
The syntax of the language is really simple:
Main
{
Call("Proc1");
}
Proc1
{
// Empty
}
I ...
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Is there a simple algorithm for generating unit tests given a function's code? [closed]
Given the abstract syntax tree (AST) of each line of a function's code, I am asked to generate code for that function's corresponding unit tests, similar to what Microsoft's IntelliTest tool does here:...
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Is it possible to make a compiler for any dynamic/script/interpreter language
Logically, not based on how cost we will spend or how much we will hire programmers to do it.
Can we (Is it possible to) make a compiler for any dynamic/script/interpreter language, like Lua, Python, ...
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Archival-quality future-proof pseudo-CPU architecture
Suppose we maintain a massive electronic library of texts/photos/videos etc., and want to ensure that these files are readable indefinitely long in the future. [Update] one of the major problems with ...
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How to practically implement a symbol table during compiler design?
I was trying compiler design with flex and bison. This is my first attempt in that sense.
For my compiler, I wanted to build a symbol table which would help in building a proper compile-time type-...
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Why `struct` unconstrained method fails to accept `null` as `T?` parameter
Considering example below, one observe that for reference type argument is successfully understood as nullable parameter. For value type conversion to T?/Nullable<T> fails.
T Method<T> ( T?...
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How does code work without getting compiled or interpreted?
I recently started researching about coding, but there are a few things that made me confused. I chose Visual Studio Code to start coding in C and Python (I was using IDLE for Python before), but ...
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In C++, If a member function can be made static with no change to functionality, are there any performance or memory benefits from doing so?
A very straightforward question.
When I think about many of the member functions I create for my classes, many of them can be made static without affecting any functionality whatsoever.
If I do so; ...
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Benefits of using a tokenizer/lexer before parsing for recusive descent parser
I am trying to build a static program analyzer for a proprietary progamming language for a school project, and am currently trying to implement the parser from scratch.
I was wondering, what are the ...
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Small confusion about time complexity
Suppose we have a code:
for(int i=0;i<n;i++) sum+=i;
We say the time function here is: f(n) = n+1+n = 2n+1. The order of the time function is 1. So, our time complexity becomes O(n).
But, for the ...
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Where is the boundary between things which can be statically typechecked, and those which must be typechecked dynamically?
I am brain storming on how to create a type system for a programming language, and what the compiler will do with the typing information. Here is what I have found, followed by the main question, ...
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Do C++ compilers optimize/pack small data types (e.g. boolean values)?
This occurred to me when looking at stencil computations in numpy. This python library compiles compute-intensive components, so I believe that it's a valid example. Here making selections on an array ...
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Which non-standard C features can I use? [closed]
C and C++ have standards, but support isn't perfect, the only available copies on the internet are drafts, and there are immensely useful things that aren't standard, such as __attribute__((cleanup)). ...
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What happens in terms of call stacks when 10000 setTimeouts are called?
Say we call 10000 setTimeouts, each with a random time, each with a few nested timeouts too. What happens in terms of the 1 call stack, or are there multiple call stacks? How does that work?
So for ...
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Why Java, C# and the like needs to be managed code
As far as I know the big argument for C#, Java and other high level languages having to be memory managed by a runtime environment is that the programmer does not take care of garbage collection or ...
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Template argument type exclusion: Would this make for a useful C++ feature?
When using templates we can have T be any type upon class instantiation. If T is a specific type that needs to be handled differently or in a special way we can specialize or partial specialize that ...
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Do compilers optimise in concurrency?
Presuming that I have written some sequential code where it can be broken down into multiple isolated tasks, it seems it might be efficient for concurrency to be introduced.
For example
print(...
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How do binary numbers interact with the CPU and cause some action to take place? [duplicate]
EDIT: Perhaps what I am misunderstanding is that when it is said that the code we type gets turned into machine code of 0s and 1s. If these 0s and 1s are the abstracted representation of their ...
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