pyrox.dev
1#!@shell@
2
3# This script wraps the LLVM `opt(1)` executable and maps the options
4# passed by old versions of GHC to the equivalents passed by newer
5# versions that support recent versions of LLVM.
6#
7# It achieves the same effect as the following GHC change externally:
8# <https://gitlab.haskell.org/ghc/ghc/-/merge_requests/8999>.
9#
10# This is used solely for bootstrapping newer GHCs from the GHC 9.0.2
11# binary on AArch64, as that is the only architecture supported by that
12# binary distribution that requires LLVM, and our later binary packages
13# all use the native code generator for all supported platforms.
14#
15# No attempt is made to support custom LLVM optimization flags, or the
16# undocumented flag to disable TBAA, or avoid
17# <https://gitlab.haskell.org/ghc/ghc/-/issues/23870>, as these are not
18# required to bootstrap GHC and at worst will produce an error message.
19#
20# It is called `subopt` to reflect the fact that it uses `opt(1)` as a
21# subprocess, and the fact that the GHC build system situation
22# requiring this hack is suboptimal.
23
24set -e
25
26expect() {
27 if [[ $1 != $2 ]]; then
28 printf >&2 'subopt: got %q; expected %q\n' "$1" "$2"
29 return 2
30 fi
31}
32
33if [[ $NIX_DEBUG -ge 1 ]]; then
34 printf >&2 'subopt: before:'
35 printf >&2 ' %q' "$@"
36 printf >&2 '\n'
37fi
38
39args=()
40
41while [[ $# -gt 0 ]]; do
42 case "$1" in
43 -enable-new-pm=0)
44 shift 1
45 ;;
46 -mem2reg)
47 expect "$2" -globalopt
48 expect "$3" -lower-expect
49 expect "$4" -enable-tbaa
50 expect "$5" -tbaa
51 args+=('-passes=function(require<tbaa>),function(mem2reg),globalopt,function(lower-expect)')
52 shift 5
53 ;;
54 -O1)
55 expect "$2" -globalopt
56 expect "$3" -enable-tbaa
57 expect "$4" -tbaa
58 args+=('-passes=default<O1>')
59 shift 4
60 ;;
61 -O2)
62 expect "$2" -enable-tbaa
63 expect "$3" -tbaa
64 args+=('-passes=default<O2>')
65 shift 3
66 ;;
67 *)
68 args+=("$1")
69 shift 1
70 ;;
71 esac
72done
73
74if [[ $NIX_DEBUG -ge 1 ]]; then
75 printf >&2 'subopt: after:'
76 printf >&2 ' %q' "${args[@]}"
77 printf >&2 '\n'
78fi
79
80exec @opt@ "${args[@]}"