Inside Bitcoin

1#!/usr/bin/env bash
2
3# Usage: env [ CC=... ] [ C_STANDARD=...] [ CXX=... ] [CXX_STANDARD=...] \
4#            [ CPPFLAGS=... ] [CFLAGS=...] [CXXFLAGS=...] [LDFLAGS=...] \
5#            [ AR=... ] [ NM=... ] [ RANLIB=... ] [ STRIP=... ] [ DEBUG=... ] \
6#            [ LTO=... ] ./gen_id [ID_SALT]...
7#
8# Prints to stdout a SHA256 hash representing the current toolset, used by
9# depends/Makefile as a build id for caching purposes (detecting when the
10# toolset has changed and the cache needs to be invalidated).
11#
12# If the DEBUG environment variable is non-empty and the system has `tee`
13# available in its $PATH, the pre-image to the SHA256 hash will be printed to
14# stderr. This is to help developers debug caching issues in depends.
15
16# This script explicitly does not `set -e` because id determination is mostly
17# opportunistic: it is fine that things fail, as long as they fail consistently.
18
19# Command variables (CC/CXX/AR) which can be blank are invoked with `bash -c`,
20# because the "command not found" error message printed by shells often include
21# the line number, like so:
22#
23#     ./depends/gen_id: line 43: --version: command not found
24#
25# By invoking with `bash -c`, we ensure that the line number is always 1
26
27(
28    # Redirect stderr to stdout
29    exec 2>&1
30
31    # Unset SOURCE_DATE_EPOCH to prevent it from leaking into tool
32    # outputs and to maximize reuse of the built package cache.
33    unset SOURCE_DATE_EPOCH
34
35    echo "BEGIN ALL"
36
37    # Include any ID salts supplied via command line
38    echo "BEGIN ID SALT"
39    echo "$@"
40    echo "END ID SALT"
41
42    echo "BEGIN FLAGS"
43    echo "CPPFLAGS=${CPPFLAGS}"
44    echo "CFLAGS=${CFLAGS}"
45    echo "CXXFLAGS=${CXXFLAGS}"
46    echo "LDFLAGS=${LDFLAGS}"
47    echo "END FLAGS"
48
49    # GCC only prints COLLECT_LTO_WRAPPER when invoked with just "-v", but we want
50    # the information from "-v -E -" as well, so just include both.
51    echo "BEGIN CC"
52    bash -c "${CC} -v"
53    bash -c "${CC} -v -E -xc -o /dev/null - < /dev/null"
54    bash -c "${CC} -v -E -xobjective-c -o /dev/null - < /dev/null"
55    echo "C_STANDARD=${C_STANDARD}"
56    echo "END CC"
57
58    echo "BEGIN CXX"
59    bash -c "${CXX} -v"
60    bash -c "${CXX} -v -E -xc++ -o /dev/null - < /dev/null"
61    bash -c "${CXX} -v -E -xobjective-c++ -o /dev/null - < /dev/null"
62    echo "CXX_STANDARD=${CXX_STANDARD}"
63    echo "END CXX"
64
65    # We use lld when cross-compiling for macOS, and it's version should
66    # be tied to LLVM. However someone compiling with GCC and -fuse-ld=lld
67    # would not see a cache bust if the LLVM toolchain was updated.
68    echo "BEGIN lld"
69    bash -c "ld.lld --version"
70    echo "END lld"
71
72    echo "BEGIN mold"
73    bash -c "mold --version"
74    echo "END mold"
75
76    echo "BEGIN AR"
77    bash -c "${AR} --version"
78    env | grep '^AR_'
79    echo "END AR"
80
81    echo "BEGIN NM"
82    bash -c "${NM} --version"
83    env | grep '^NM_'
84    echo "END NM"
85
86    echo "BEGIN RANLIB"
87    bash -c "${RANLIB} --version"
88    env | grep '^RANLIB_'
89    echo "END RANLIB"
90
91    echo "BEGIN STRIP"
92    bash -c "${STRIP} --version"
93    env | grep '^STRIP_'
94    echo "END STRIP"
95
96    echo "BEGIN LTO"
97    echo "LTO=${LTO}"
98    echo "END LTO"
99
100    echo "END ALL"
101) | if [ -n "$DEBUG" ] && command -v tee > /dev/null 2>&1; then
102        # When debugging and `tee` is available, output the preimage to stderr
103        # in addition to passing through stdin to stdout
104        tee >(cat 1>&2)
105    else
106        # Otherwise, passthrough stdin to stdout
107        cat
108    fi | ${SHA256SUM} - | cut -d' ' -f1
109