JKF
76 lines
1.5 KiB
Markdown
76 lines
1.5 KiB
Markdown
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footer: Topics in Compilers and Concurrency · Julius Fischer · 10.06.2026
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---
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# Destination Calculus:
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## A Linear 𝜆-Calculus for Purely Functional Memory Writes
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### Topics in Compiler and Concurrency
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#### Julius Fischer
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###### 10. Juni 2026
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---
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# What are Destinations?
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- Destination Passing Style
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- Imperative
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- Function takes destination instead of returning structure
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---
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# Example in C
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```
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int* vec_add(int v1[], int v2[], int size) {
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int* res = malloc(size * sizeof(int));
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for (int i = 0; i < size; i++) {
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res[i] = v1[i] + v2[i];
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}
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return res;
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}
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```
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- Add an 'out parameter'
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```
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void dps_vec_add(int res[], int v1[], int v2[], int size) {
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for (int i = 0; i < size; i++) {
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res[i] = v1[i] + v2[i];
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}
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}
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```
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---
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# Motivation for DPS
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- Typical functional map implementation
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```
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map f (x:xs) = (f x : map f xs1)
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> (f x : map f xs)
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> (map f x1 : (f x2 : map f xs2))
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> ...
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```
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- Not tail recursive
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- Performance issue
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- Inefficient stack growth
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```
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map f (x:xs) dest = map f xs (push dest (f x))
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> map f xs1 (push dest (f x1))
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> map f xs2 (push dest (f x2))
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```
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---
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# DPS in functional languages
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- Just add pointers to mutable data?
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- $Int \mapsto Int \mapsto Int \mapsto \textcolor{red}{T}$
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- $\textcolor{red}{T *}\mapsto Int \mapsto Int \mapsto Int \mapsto Void$
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---
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# Destination Calculus
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- It's
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---
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# Referenes
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