From compilerwrapper.cpp:

/*
Older icecream versions assume the compiler is always GCC. This can
be fixed on the local side, but remote nodes would need icecream upgrade.
As a workaround icecc-create-env includes this wrapper binary in the environment
if clang is to be used as well, that will either call clang or the real gcc.
Which one depends on an extra argument added by icecream.
*/

While not strictly needed with newer version of IceCC, it would be good to include it in the same way as icecc-create-env does to ensure compatibility of the generated tarballs with older IceCC versions.

The compiler_binaries() function (including the _clang / _gcc variants) do not propagate errors upwards, and will panic! on certain errors. Returning the errors would allow for better reporting and (potentially) recovery.

For ELF binaries, the DT_RPATH and DT_RUNPATH entries may contain the $LIB string, which must be expanded to lib, lib32, lib64, etc. as needed for the target platform.

The util::find_program() function assumes that when it encounters a file in one of the search directories, it will be executable. It would be more robust to add the needed check on the file metadata.

Currently the checksum used to determine whether a new tarball is needed is done over the contents of the scanned executables, but this does not take into account other data added to the tarball symbolic links or text files.

While the current approach works decently, when something in the Popsicle code changes, the cache will be considered to be valid, when it might not.

$ ~/git/popsicle/target/release/popsicle ./src/third_party/llvm-build/Release+Asserts/bin/clang
Error: cannot find external program: "./src/third_party/llvm-build/Release+Asserts/bin/clang"
$ ~/git/popsicle/target/release/popsicle `pwd`/src/third_party/llvm-build/Release+Asserts/bin/clang
$HOME/.cache/popsicle/clang/clang-6.0.0.tar.gz

The pointed clang is a normal binary file:

$ file ./src/third_party/llvm-build/Release+Asserts/bin/clang
clang: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, stripped

Today I updated to Clang 5.0.0 from version 4.0.1, and after running Popsicle once, the cache directory looks as follows:

% ls -l ~/.cache/popsicle/clang/
total 93448
-rw-r--r-- 1 aperez aperez       64 sep 14 10:43 checksum
-rw-r--r-- 1 aperez aperez 46277102 sep 13 20:20 clang-4.0.1.tar.gz
-rw-r--r-- 1 aperez aperez 49399653 sep 14 10:43 clang-5.0.0.tar.gz
-rw-r--r-- 1 aperez aperez        5 sep 14 10:43 compiler-version
% cat ~/.cache/popsicle/clang/compiler-version 
5.0.0
%

In one hand, checksumming did correctly detect the need to generate a new tarball, but the old clang-4.0.1.tar.gz one was left behind.

This is due to DummyCache missing an implementation of Cache::path_for. Which means that the fall-back “caching” mechanism (which does not cache) is broken.

For ELF binaries, the DT_RPATH and DT_RUNPATH entries may contain the $PLATFORM string, which must be expanded to the output of uname -m, e.g. x86_64.