[libc] Add a separate algorithm_test.

[gchatelet]

Thx @lntue.
I've been able to reproduce the error with cmake fullbuild -> ninja llvmlibc -> ninja check-libc
And indeed, from a clean CMake folder cmake fullbuild -> ninja check-libc passes.

I've extracted both compilation command lines and they are identical. This is puzzling.

/redacted_home/build-llvm/download/clang/bin/clang++
--sysroot=/redacted_home/build-llvm/download/sysroot
-D_DEBUG
-D_GNU_SOURCE
-D__STDC_CONSTANT_MACROS
-D__STDC_FORMAT_MACROS
-D__STDC_LIMIT_MACROS
-I/redacted_home/llvm-project_rel_compiled-with-clang/projects/libc/test/src/string/memory_utils
-I/redacted_home/git/llvm-project/libc/test/src/string/memory_utils
-I/redacted_home/llvm-project_rel_compiled-with-clang/include
-I/redacted_home/git/llvm-project/llvm/include
-I/redacted_home/git/llvm-project/libc
-I/redacted_home/llvm-project_rel_compiled-with-clang/projects/libc
-I/redacted_home/llvm-project_rel_compiled-with-clang/projects/libc/include
-fPIC
-fno-semantic-interposition
-fvisibility-inlines-hidden
-Werror=date-time
-Werror=unguarded-availability-new
-Wall
-Wextra
-Wno-unused-parameter
-Wwrite-strings
-Wcast-qual
-Wmissing-field-initializers
-pedantic
-Wno-long-long
-Wc++98-compat-extra-semi
-Wimplicit-fallthrough
-Wcovered-switch-default
-Wno-noexcept-type
-Wnon-virtual-dtor
-Wdelete-non-virtual-dtor
-Wsuggest-override
-Wstring-conversion
-Wmisleading-indentation
-fdiagnostics-color
-ffunction-sections
-fdata-sections
-O3
-DNDEBUG
-UNDEBUG
-march=znver3
-std=c++17
-MD
-MT
projects/libc/test/src/string/memory_utils/CMakeFiles/libc.test.src.string.memory_utils.algorithm_test.dir/algorithm_test.cpp.o
-MF
projects/libc/test/src/string/memory_utils/CMakeFiles/libc.test.src.string.memory_utils.algorithm_test.dir/algorithm_test.cpp.o.d
-o
projects/libc/test/src/string/memory_utils/CMakeFiles/libc.test.src.string.memory_utils.algorithm_test.dir/algorithm_test.cpp.o
-c
/redacted_home/git/llvm-project/libc/test/src/string/memory_utils/algorithm_test.cpp

[gchatelet]

Ok I get it, kind of. #include <string> in the tests pulls a reference to pthread down in the GCC C++ library. I don't quite understand why but this is is resolved to llvm libc's header in the cmake build directory /redacted_home/llvm-project_rel_compiled-with-clang/projects/libc/include/pthread.h.
But that header is incomplete, the following symbols are missing : pthread_key_t, pthread_once_t, pthread_cond_broadcast, pthread_cond_signal, pthread_cond_wait, pthread_cond_timedwait.

Looking at the cmd line though, I can't find anything responsible for preferring llvm-libc headers over the system ones.

In fact I think we should have two types of tests:

1. Unit tests testing internal building blocks,
2. Functional tests testing the behavior of the libc interface.

In full build mode we should only run functional tests (2), this would allow us to use standard C++ in 1.
This can be done by splitting the add_libc_unittest function in : add_libc_unittest and add_libc_functionaltest
We could either have a separate functionaltest folder at the root of the project.

What do you think @sivachandra @courbet @michaelrj @lntue ?

In the meantime we could disable algorithm_test when FULLBUILD is enabled.

[courbet]

As I've mentioned before I'm all for splitting off tests into those that do not need to . I've seen the pain of all these patches re-implementing basic functionality for gtest and libc++. If we remain in that situation we'll end up not unit testing enough.

[gchatelet]

I'll upload a new patch to disable this test whe FULLBUILD is enabled.

[gchatelet]

• [reland] algorithm_test.cpp

[gchatelet]

rebase

[gchatelet]

@lntue let me know if this looks good to you so I can move on with my refactoring. I'm currently blocked on this :)

[gchatelet]

It's Independence Day today so I don't expect any discussions to occur before Wed. I will submit this now. We can revert later if you disagree.

libc/test/src/string/memory_utils/CMakeLists.txt

 add_libc_unittest(
   utils_test
   SUITE
     libc_string_unittests
   SRCS
     address_test.cpp
-    # algorithm_test.cpp
     backend_test.cpp
     elements_test.cpp
     memory_access_test.cpp
     utils_test.cpp
   COMPILE_OPTIONS
     ${LIBC_COMPILE_OPTIONS_NATIVE}
     -ffreestanding
     -pthread
   DEPENDS
     libc.src.string.memory_utils.memory_utils
     libc.src.__support.CPP.array
     libc.src.__support.CPP.array_ref
 )
+
+if(NOT LLVM_LIBC_FULL_BUILD)
+# Disabling this unittest in fullbuild mode as #include<sstream> is pulling an
+# incomplete pthread implementation from llvm-libc.
+add_libc_unittest(
+  algorithm_test
+  SUITE
+    libc_string_unittests
+  SRCS
+    algorithm_test.cpp
+  DEPENDS
+    libc.src.string.memory_utils.memory_utils
+    libc.src.__support.CPP.array
+    libc.src.__support.CPP.array_ref
+)
+endif()