Fix fatal error: math.h no such file or directory

[winksaville]

This fixes #3016 by adding lines back introduced in PR #824. This code conditionally added llvm include directory only if it wasn't already included. These lines were a small part of PR #2976 which adds LLVM 7.0.1 compatibility.

[SeanTAllen]

Thanks @winksaville. Can you amend your commit to be meaningful for what is fixed without having to look at the issue tracker? Referring back to the issue is fine, but "Fix issue #3016" won't be helpful in the future when bisecting to find problems, which for example I just did to find the fix to #3015. Meaningful commit comments helped me narrow down where to look quite a lot and I had to dig through 2 years of commits. Thanks.

[winksaville]

Your are correct, my commit message was poor, I've changed the title and commit message, let me know if you'd like something more/different.

[jemc]

Sorry I regressed #824, but my change that you're reverting was solving a real problem that I encountered when trying to work on this. See my commit message for details:
ad22b15

Is it possible to keep the fix from #824 while using cflags instead of includedir? As I mentioned in my commit message, includedir only lists one include dir, while cflags lists them all, which is important in some cases such as those I mentioned in the commit message.

[winksaville]

Sorry I regressed #824, but my change that you're reverting was solving a real problem that I encountered when trying to work on this. See my commit message for details:
ad22b15

Is it possible to keep the fix from #824 while using cflags instead of includedir? As I mentioned in my commit message, includedir only lists one include dir, while cflags lists them all, which is important in some cases such as those I mentioned in the commit message.

Nothing is impossible, its just software, I'll see what I can do.

[winksaville]

Changed the code back to using --cflags and it uses a loop to handle multiple directories.

[winksaville]

Bummer, seems my use of "[[" "]]" doesn't work with ubuntu, looking into it.

[winksaville]

The problem is ubuntu default SHELL is dash not bash, changed to using grep.

[jemc]

Did you mean to leave this in? If so, can you expand the comment to describe what it is testing and when you'd want to use it?

[winksaville]

It can be used when enabling line 444:

# Used for testing
#llvm.cflags := -I/usr/include -march=x86-64  -I  /sec/time -I /usr/local/include -I   /3/4 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt -fPIC -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -pedantic -Wno-long-long -Wno-comment -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/xyz/abc

I could remove both or add a documentation like:

# Enable the "done:" target for testing when the commented out line above is enabled:
# llvm.cflags := -I/usr/include -march=x86-64 ....

On the face of it, its easier to remove both. Its too bad we don't have any good way to test Makefiles. So what do you prefer, or maybe something else?

[jemc]

I'd suggest removing both, but I'd also be okay with keeping them if you add the comment explaining it.

[winksaville]

@jemc and I talked on slack and decided to remove the "test" code.

[jemc]

Thank you for the extra work!

[jemc]

Good to merge when CI passes.

[SeanTAllen]

This breaks building on FreeBSD.

[SeanTAllen]

Huh, well it broke one FreeBSD vm I am using but not another. Good times!

[winksaville]

@SeanTAllen , where can I find the build breakage, I'm not familiar where/how the FreeBSD builds are built? Is there a slack conversation about this?

[winksaville]

@SeanTAllen , where can I find the build breakage, I'm not familiar where/how the FreeBSD builds are built? Is there a slack conversation about this?

To answer my own question, the conversation on slack is here and the build breakage is here

[SeanTAllen]

The breakage in the VMs I've tried that are available for vagrant is that:

echo "-I/usr/local/llvm60/include -O2 -pipe -DNDEBUG -fstack-protector -isystem /usr/local/include -fno-strict-aliasing -fPIC -Werror=date-time -Werror=unguarded-availability-new -Wall -W -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wdelete-non-virtual-dtor -Wstring-conversion -fcolor-diagnostics -ffunction-sections -fdata-sections -O2 -pipe -DNDEBUG -fstack-protector -isystem /usr/local/include -fno-strict-aliasing -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS" | grep -oE -- '(^| )-I\s*\S+'

Doesn't work on FreeBSD for unknown reasons. It returns nothing.

[winksaville]

The breakage in the VMs I've tried that are available for vagrant is that:

echo "-I/usr/local/llvm60/include -O2 -pipe -DNDEBUG -fstack-protector -isystem /usr/local/include -fno-strict-aliasing -fPIC -Werror=date-time -Werror=unguarded-availability-new -Wall -W -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wdelete-non-virtual-dtor -Wstring-conversion -fcolor-diagnostics -ffunction-sections -fdata-sections -O2 -pipe -DNDEBUG -fstack-protector -isystem /usr/local/include -fno-strict-aliasing -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS" | grep -oE -- '(^| )-I\s*\S+'

Doesn't work on FreeBSD for unknown reasons. It returns nothing.

Is the above from lines 439 440:

llvm.get_include_dirs := "echo '$(llvm.cflags)' | grep -oE -- '(^| )-I\s*\S+' | sed 's/^\s*-I\s*//'"
llvm.include_dirs := $(shell sh -c $(llvm.get_include_dirs))

I ask because your "echo" above seems to be mssing the | sed ... .

I'd like to add some $(warnings ...) to see first hand what is happening and see if we should make additional changes. Do you want me to look at llvm 6 or just llvm 7?

[SeanTAllen]

I broke it down to what would actually be failing. On the BSD vms I used, for no apparent reason that grep returned nothing. So it didn't matter that there was no sed.

You can give it a try in this BSD vm using Vagrant:

https://app.vagrantup.com/generic/boxes/freebsd12

It works in Cirrus-Ci for reasons unknown to me and it works with the same version of Grep (at least according to the version numbers) on MacOS.

So, ¯_(ツ)_/¯.