commit 993ca957ef56fefbb604aceb50d65fc880f63882
parent 84fbd00237180b654feb38cd2915039d79033716
Author: Quentin Carbonneaux <quentin.carbonneaux@yale.edu>
Date: Wed, 23 Mar 2016 22:33:36 -0400
typos in llvm.txt (thanks lucie)
Diffstat:
1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/doc/llvm.txt b/doc/llvm.txt
@@ -4,31 +4,31 @@
Both QBE and LLVM are compiler backends using an SSA
-representation. This document will explain why the
-advanced stage in which LLVM is does not make QBE a
-redundant project. Obviously, everything following is
-probably biased, because written by me.
+representation. This document will explain why LLVM
+does not make QBE a redundant project. Obviously,
+everything following is probably biased, because
+written by me.
- Scope
-------
-QBE is a much smaller scale projects with different
-goals than LLVM.
+QBE is a much smaller scale project with different goals
+than LLVM.
* QBE is for amateur language designers.
It does not address all the problems faced when
conceiving an industry-grade language. If you are
toying with some language ideas, using LLVM will
- feel like throwing your backpack in a truck, but
- using QBE will feel more like biking.
+ be like hauling your backpack in a truck, but using
+ QBE will feel more like biking.
* QBE is about the first 70%, not the last 30%.
It attempts to pinpoint, in the extremely vast
compilation literature, the optimizations that get
- you 70% of the performance in 10% of the code needed
- to scrape the last bits of performance.
+ you 70% of the performance in 10% of the code of
+ full blown compilers.
For example, copy propagation on SSA form is
implemented in 160 lines of code in QBE!
@@ -68,8 +68,8 @@ are a few things provided in QBE to consider.
* LLVM IR is more cluttered with memory operations.
- Implementing SSA construction is hard, and to save
- its frontends from having to do it, LLVM provides
+ Implementing SSA construction is hard. To save its
+ users from having to implement it, LLVM provides
stack slots. This means that one increment of
a variable `v` will be composed of three LLVM
instructions: one load, one add, and one store.
@@ -87,13 +87,13 @@ are a few things provided in QBE to consider.
For the sake of advanced optimizations and
correctness, LLVM has complex IL types. However,
- only a few types are really first class in the IL
- and many operations of source languages require
- casts to be compiled.
+ only a few types are really first class and many
+ operations of source languages require casts to be
+ compiled.
Because QBE makes a much lighter use of types, the
IL is more readable and shorter. It can of course be
argued back that correctness of QBE is jeoparadized,
- but remember that, in practice, the large amounts
+ but remember that, in practice, the large amount
of casts necessary in LLVM IL is compromizing the
overall effectiveness of the type system.
