Questions tagged [compilers]
Compilers are implementations of programming languages which convert source code into another format, such as a binary executable, bytecode, or another programming language. Use this tag for questions about the design or implementation of compilers. This contrasts with interpreters, which execute source code directly.
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What is best practice for a programming language which allows more than one syntax for class method invocations? [closed]
Consider the following code written in a syntax consistent with the programming language known as "python":
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In C, which approach is preferable: modifying a pointer's address within a void function or assigning the mutated pointer through its return value? [closed]
I have two conflicting theories regarding the optimal approach when passing the address of a pointer, particularly within a function like insert_front for a linked list. I seek insights based on ...
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Expressing runtime constraints with trait-bounds
I've recently listened to Corecursive episode with John A De Goes and there's one thing that really got me thinking: the idea of type class laws pertaining to performance guarantees. The example ...
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Why do so many programming languages not have a "built-in" way to do simple math functions?
Note 1: My question is not about the factorial function. It's about "simple math functions" that high-school level pocket calculators can do, but most programming languages cannot do without ...
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How to determine the meaning of a polymorphic operator?
Some operators have multiple meanings.
For example:
- represents the prefix negative, or it can represent the infix ...
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How might we convert type declarations into constructor calls? [closed]
Suppose that we have two languages, A and B.
In language A, there are a lot of data-type declarations.
In language B there are no data-type declarations to the left of the assignment operator, but ...
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What, if any, runtime cost is incurred by using 64-bit ints on 32-bit platforms in LLVM?
I'm writing a language frontend for LLVM, and I noticed that the IR docs say that integers of (almost)any width can be used without limit. I presume this to mean that LLVM or its backends convert ...
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Are enum members literals or constants in an IR?
While implementing enums in Tyr, I just realized that enum constants are the only form of literal-like entity that is not represented like a literal in the intermediate representation.
The enum ...
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How to ensure coherent choices of representatives in an e-graph?
E-graphs are a neat intermediate representation for program transformations and optimisations, which group program terms into equivalence classes (e-classes). An optimising compiler can then select ...
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Data structures for scopes and variable shadowing
Let's say I have some code in my target language like:
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What are the tradeoffs between using sea of nodes, CFG of basic blocks, and egraphs for compiler optimizations?
I've heard of "sea of nodes" intermediate representations mostly in the context of just-in-time compilation (JVM, V8, Graal) whereas intermediate representations such as LLVM IR are used in ...
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What are some techniques for faster, fine-grained incremental compilation and static analysis?
An incremental compiler is one which only needs to recompile the parts of a program which changed since the last output, as opposed to a batch compiler which must re-compile everything. Incremental ...
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How to ensure that an optimising compiler will terminate?
An optimising compiler typically applies some set of rewrites to some intermediate representation of the program, replacing terms with other terms which are supposed to be equivalent but more ...
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Can type-checking algorithms be practically generated from formal descriptions of type systems?
It's well-known that a formal grammar (a formal description of a language's syntax) can be used to programmatically generate a parser (an algorithm which analyses that syntax); tools which do this are ...
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How to ensure correct transformations with `break`, `continue` and other context-dependent statements?
I have a compiler backend which targets high-level languages, by building an abstract syntax tree for the output and then using this to generate code ─ that is, this tree is really an intermediate ...
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Can you, should you, go straight from AST to SSA?
I'm beginning to read Appel's book Modern Compiler Implementation in C. The book is about 25 years old, so maybe it's not so "modern" anymore, I don't know. I'm skimming the book and it ...
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Why has there been little recent work on GPU compiler phase optimization?
While GPU compiler phase optimization has been shown to improve performance significantly (e.g. https://link.springer.com/chapter/10.1007/978-3-319-75178-8_35), there has been very little follow-up ...
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What languages give you access to the AST to modify during compilation?
Are there any languages which allow you to get access to the AST during compile time, to use some part of the AST to generate code, or to possibly rewrite the code/AST to optimize it in a heuristic ...
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Why link the entire static library rather than only the needed functions?
This is more about compiler implementation than language design but when statically linking a library (e.g. in Swift) the entire library is linked even if only a handful of the functions are actually ...
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What are the key steps to compiling a custom programming language that is similar to Rust (typechecking, type inference, and borrow checking)?
I have been working on a custom programming language for a bit, and keep coming back to the fact that I am not easily visualizing in my mind how the compiler will work past the step of creating the ...
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What parts of the code can be easily shared between the LSP and the Compiler?
I was originally thinking to design the compilier upfront as a compiler and LSP server as well, but the answers there dissuaded me from making them share all code. But, I would still like them to ...
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Why is it so difficult to implement the first Futamura projection?
The Futamura projections are a series of three transformations that can be performed on interpreters, compilers, and compiler-compilers respectively. These transformations rely on a specializer which ...
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Why is it so hard to evaluate functions with constant arguments at compile-time?
I noticed C23 has constexpr but only for variables, not for functions. While C++ does, this would allow a function to be defined in such a way that if the function ...
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What are the pros and cons of a compiler with a single-pass parser?
Assume you are tasked with writing a compiler for a language that can be parsed in a single pass, like C, but does not necessarily have to be. What are the pros and cons for doing this? Would you do ...
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What are the pros and cons of single-pass compilers?
Okay, we all know the standard compiler architecture: a batch program with multiple passes for parsing, optimizing, and generating code.
Suppose you wanted to go all Turbo Pascal and implement a ...
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What are the pitfalls of using an existing IR/compiler infrastructure like LLVM?
Using something like LLVM when designing a compiler has a lot of advantages, since tons of work can be saved by using an existing optimizer and code generation for a variety of platforms. Even large, ...
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What are the pros/cons of a tree-based interpreter vs a bytecode-VM-based interpreter?
Based on this closed question.
Basically, why would one choose a pure interpreter for a language implementation as opposed to a virtual machine/bytecode approach like Java or Python (even if at ...
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When is ABI stability “worth it”?
ABI stands for application binary interface, and it represents how different precompiled components of a program interact. This can be a program calling out to an OS function or part of the language ...
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How can we backpatch differently-sized jump instructions?
Consider a compiler whose target language is some virtual machine bytecode. The jump instructions have to encode the size of their jumps. For example, in JVM bytecode the ...
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How can a compiler's parse errors be tested?
There are fairly straightforward ways to test a compiler's behaviour on valid programs: most obviously, build a suite of programs to run through the compiler, and know what should happen when they run....
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How do I make LLVM actually inline anything?
I've been working on a draft of a Trilangle compiler using LLVM. Out of curiosity, I took the generated IR (given the Trilangle program ?!oi@) and plugged it into ...
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How can an abstract-syntax tree be converted into linear three-address code?
I have an abstract-syntax tree (AST) for a language, and I'd like to use some sort of three-address code (TAC) to represent the program in a linear way, before converting it to assembly.
How do I do ...
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What are some caveats to be careful about when implementing the `?:` (ternary conditional) operator?
Thus far, I see two things that can go wrong when implementing the ?: (ternary conditional) operator:
PHP famously incorrectly implemented the ...
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How does a compiler know that an identifier in an expression refers to a memory location, or the value stored at that location?
There are situations during compilation when some identifier represents a particular value ("contained" in a variable, etc), but sometimes it references the variable's memory location ...
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How could I use the TypeScript Compiler API to compile TypeScript to ActionScript 3 bytecode? [closed]
TypeScript is a superset of ECMAScript and its compiler supports targetting ECMAScript 3; it even supports yield and await based ...
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How to implement a REPL for a compiled language?
Implementing a REPL is relatively straightforward for an interpreted language; the interpreter maintains the program state as normal, and evaluates each separate statement as normal, just using the ...
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When you write regex engines how do you know if question marks `?` mean zero or one of if they refer to non-capturing groups?
When you write regulair expression (regex) engines, how do you tell ....
if ? means zero or one
...or if...
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How do I implement coroutines on WebAssembly?
I am building a compiler targeting WebAssembly for a language that makes heavy use of first-class coroutines. WASM doesn't have native coroutine support (yet), so I have to emulate it. Given the ...
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Can regex be compiled into efficient machine code?
Most languages that have regex have a regex parsing library that interprets the regex at runtime and matches them to strings. I am a fan of eliminating as much runtime overhead as possible, and as ...
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How to transpile goto to a language that lacks it?
I'm writing a transpile for a C-like language to Javascript, which lacks a goto statement. Unfortunately the existing library code contains a lot of ...
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How would I allow a variety of different syntaxes for passing arguments into MathJax or LaTeX commands? [closed]
What is LaTeX
If you already know what LaTeX is, then skip down the the section labeled "sloppy syntax".
There is a type-setting language known as LaTeX.
LaTeX even has its very own Stack ...
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What is defunctionalisation useful for?
Defunctionalisation refers to program transformations which replace first-class functions and closures with conventional data structures (e.g. structs and enums), so that higher-order functions become ...
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Why would you choose a LLVM over a GCC back-end or vice versa for a compiled language?
LLVM and GCC are two popular choices for back-ends. They both have good compilation frameworks. What are the advantages and disadvantages of each?
Credit to Mousetail for the idea on Area 51
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When compiling to binary, how do compilers provide debug symbols/source maps and context?
I've written a compiler, and it currently outputs assembly. I'd like to make it so that when I assemble it into a final binary, I can pass the binary to a debugger and view it with source mappings, so ...
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How would you design a compiler upfront to be both a compiler and a LSP server?
For most modern programming languages, an LSP (Language Server Protocol) server needs to be developed, which requires reusing/rewriting some of the existing code that is already used by the compiler. ...
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What are the benefits to self-hosting compilers?
The article "Reflections on Trusting Trust", published in 1984, shows how it's possible to inject a vulnerability into a self-hosting compiler and cover up your tracks. However, self-hosting ...
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How to transpile labelled break/continue statements to a high-level language which lacks them?
Suppose I am writing a source-to-source compiler (also called a transpiler) from one high-level imperative language to another, where the source language allows labelled statements to be targeted by <...
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How can switch statements with sparse cases be compiled?
A switch statement, as in languages like C, Java or Javascript, allows branching based on different cases of some value (the "scrutinee"). It's well known ...
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Could ownership be inferred?
Rust famously has the concept of ownership vs. borrowing as part of its type system. This allows some level of automatic memory management ─ that is, heap allocations are freed when their owner goes ...
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What ways are there to determine if cascading compile errors are dependent or independent?
In my experience as a developer, a single syntax error made in a long program can result in a long cascading list of error messages, only the first of which is directly relevant to the solution. For ...
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