[CMake] Fix the value of `config.target_cflags` for non-macOS Apple platforms. Attempt #3.

The main problem here is that `-*-version_min=` was not being passed to
the compiler when building test cases. This can cause problems when
testing on devices running older OSs because Clang would previously
assume the minimum deployment target is the the latest OS in the SDK
which could be much newer than what the device is running.

Previously the generated value looked like this:

`-arch arm64 -isysroot
<path_to_xcode>/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS12.1.sdk`

With this change it now looks like:

`-arch arm64 -stdlib=libc++ -miphoneos-version-min=8.0 -isysroot
<path_to_xcode>/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS12.1.sdk`

This mirrors the setting of config.target_cflags on macOS.

This change is made for ASan, LibFuzzer, TSan, and UBSan.

To implement this a new `get_test_cflags_for_apple_platform()` function
has been added that when given an Apple platform name and architecture
returns a string containing the C compiler flags to use when building
tests. This also calls a new helper function `is_valid_apple_platform()`
that validates Apple platform names.

This is the third attempt at landing the patch.

The first attempt (r359305) had to be reverted (r359327) due to a buildbot
failure. The problem was that calling `get_test_cflags_for_apple_platform()`
can trigger a CMake error if the provided architecture is not supported by the
current CMake configuration. Previously, this could be triggered by passing
`-DCOMPILER_RT_ENABLE_IOS=OFF` to CMake. The root cause is that we were
generating test configurations for a list of architectures without checking if
the relevant Sanitizer actually supported that architecture. We now intersect
the list of architectures for an Apple platform with
`<SANITIZER>_SUPPORTED_ARCH` (where `<SANITIZER>` is a Sanitizer name) to
iterate through the correct list of architectures.

The second attempt (r363633) had to be reverted (r363779) due to a build
failure. The failed build was using a modified Apple toolchain where the iOS
simulator SDK was missing. This exposed a bug in the existing UBSan test
generation code where it was assumed that `COMPILER_RT_ENABLE_IOS` implied that
the toolchain supported both iOS and the iOS simulator. This is not true. This
has been fixed by using the list `SANITIZER_COMMON_SUPPORTED_OS` for the list
of supported Apple platforms for UBSan. For consistency with the other
Sanitizers we also now intersect the list of architectures with
UBSAN_SUPPORTED_ARCH.

rdar://problem/50124489

Differential Revision: https://reviews.llvm.org/D61242

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@373405 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 0 deletions

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index d2da0496b..875acc83b 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -208,6 +208,32 @@ macro(get_test_cc_for_arch arch cc_out cflags_out)
   endif()
 endmacro()
 
+# Returns CFLAGS that should be used to run tests for the
+# specific apple platform and architecture.
+function(get_test_cflags_for_apple_platform platform arch cflags_out)
+  is_valid_apple_platform("${platform}" is_valid_platform)
+  if (NOT is_valid_platform)
+    message(FATAL_ERROR "\"${platform}\" is not a valid apple platform")
+  endif()
+  set(test_cflags "")
+  get_target_flags_for_arch(${arch} test_cflags)
+  list(APPEND test_cflags ${DARWIN_${platform}_CFLAGS})
+  string(REPLACE ";" " " test_cflags_str "${test_cflags}")
+  string(APPEND test_cflags_str "${COMPILER_RT_TEST_COMPILER_CFLAGS}")
+  set(${cflags_out} "${test_cflags_str}" PARENT_SCOPE)
+endfunction()
+
+function(is_valid_apple_platform platform is_valid_out)
+  set(is_valid FALSE)
+  if ("${platform}" STREQUAL "")
+    message(FATAL_ERROR "platform cannot be empty")
+  endif()
+  if ("${platform}" MATCHES "^(osx|((ios|watchos|tvos)(sim)?))$")
+    set(is_valid TRUE)
+  endif()
+  set(${is_valid_out} ${is_valid} PARENT_SCOPE)
+endfunction()
+
 set(ARM64 aarch64)
 set(ARM32 arm armhf)
 set(HEXAGON hexagon)