Updated Note Rust performance fixes (markdown)

Note-Rust-performance-fixes.md

@@ -2,28 +2,37 @@ This is a page of random performance ideas, mostly from pcwalton.
 
 pcwalton:
 graydon: there are a bunch of unnecessary allocations in trans
+
 pcwalton:
 I fixed a bunch of 'em but there are certainly more
+
 pcwalton:
 one thing that would very much help is a SmallVector in libstd
 
 pcwalton:
 fail() really needs to be a lang_item and it needs to be parameterized over ToStr
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 pcwalton:
 the idea being that if you're failing with a constant string
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 pcwalton:
 it should not call upcall_new_str_uniq() at the site of failure
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 pcwalton:
 rather it should pass a string slice (&static/str) to a function which itself copies the string
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 pcwalton:
 move the copy out of line
+
 pcwalton:
 likewise fmt! generates a ton of code. most of the time the unique string it produces is not really being used, except to be written once and thrown away
+
 graydon:
 mhm
 
 pcwalton:
 (1) stop zeroing stuff out to revoke cleanups, use a flag instead to indicate whether the dtor needs to be run (this is potentially a quite large win)
+
 pcwalton:
 (2) try to coalesce failure landing pads instead of duplicating the cleanups all the time