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authorCarl Dong <contact@carldong.me>2021-03-12 17:39:11 -0500
committerCarl Dong <contact@carldong.me>2021-04-08 20:17:20 -0400
commitfa872c9af397837bb17859b5f43adec71239682a (patch)
treeb51ce283cbfc1262d05db67206f4590364709efd /depends/gen_id
parent6664211be2b664dd471d7aeea12fcf2859dba860 (diff)
depends: Fix id_string invocations
We now use a script named gen_id to generate the base build_id/host_id. This solves 2 problems: 1. GNU Make special-casing exit code 127 (command not found) meant that warnings about missing tools would propagate to the user's terminal and broke our opportunistic build_id construction. 2. This change ensures that we don't have arbitrary characters in our make variables that would be misinterpreted by Make. See comments in depends/Makefile and depends/gen_id for more information.
Diffstat (limited to 'depends/gen_id')
-rwxr-xr-xdepends/gen_id74
1 files changed, 74 insertions, 0 deletions
diff --git a/depends/gen_id b/depends/gen_id
new file mode 100755
index 0000000000..ac69ca7ee1
--- /dev/null
+++ b/depends/gen_id
@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+
+# Usage: env [ CC=... ] [ CXX=... ] [ AR=... ] [ RANLIB=... ] [ STRIP=... ] \
+# [ DEBUG=... ] ./build-id [ID_SALT]...
+#
+# Prints to stdout a SHA256 hash representing the current toolset, used by
+# depends/Makefile as a build id for caching purposes (detecting when the
+# toolset has changed and the cache needs to be invalidated).
+#
+# If the DEBUG environment variable is non-empty and the system has `tee`
+# available in its $PATH, the pre-image to the SHA256 hash will be printed to
+# stderr. This is to help developers debug caching issues in depends.
+
+# This script explicitly does not `set -e` because id determination is mostly
+# opportunistic: it is fine that things fail, as long as they fail consistently.
+
+# Command variables (CC/CXX/AR) which can be blank are invoked with `bash -c`,
+# because the "command not found" error message printed by shells often include
+# the line number, like so:
+#
+# ./depends/gen_id: line 43: --version: command not found
+#
+# By invoking with `bash -c`, we ensure that the line number is always 1
+
+(
+ # Redirect stderr to stdout
+ exec 2>&1
+
+ echo "BEGIN ALL"
+
+ # Include any ID salts supplied via command line
+ echo "BEGIN ID SALT"
+ echo "$@"
+ echo "END ID SALT"
+
+ # GCC only prints COLLECT_LTO_WRAPPER when invoked with just "-v", but we want
+ # the information from "-v -E -" as well, so just include both.
+ echo "BEGIN CC"
+ bash -c "${CC} -v"
+ bash -c "${CC} -v -E -xc -o /dev/null - < /dev/null"
+ bash -c "${CC} -v -E -xobjective-c -o /dev/null - < /dev/null"
+ echo "END CC"
+
+ echo "BEGIN CXX"
+ bash -c "${CXX} -v"
+ bash -c "${CXX} -v -E -xc++ -o /dev/null - < /dev/null"
+ bash -c "${CXX} -v -E -xobjective-c++ -o /dev/null - < /dev/null"
+ echo "END CXX"
+
+ echo "BEGIN AR"
+ bash -c "${AR} --version"
+ env | grep '^AR_'
+ echo "ZERO_AR_DATE=${ZERO_AR_DATE}"
+ echo "END AR"
+
+ echo "BEGIN RANLIB"
+ bash -c "${RANLIB} --version"
+ env | grep '^RANLIB_'
+ echo "END RANLIB"
+
+ echo "BEGIN STRIP"
+ bash -c "${STRIP} --version"
+ env | grep '^STRIP_'
+ echo "END STRIP"
+
+ echo "END ALL"
+) | if [ -n "$DEBUG" ] && command -v tee > /dev/null 2>&1; then
+ # When debugging and `tee` is available, output the preimage to stderr
+ # in addition to passing through stdin to stdout
+ tee >(cat 1>&2)
+ else
+ # Otherwise, passthrough stdin to stdout
+ cat
+ fi | ${SHA256SUM} - | cut -d' ' -f1