monorepo fixup: Merge --theirs all the untracked dirs in swift/master

Because LLDB branched significantly later than the other tracked
directories, the generated content for swift/master has a much newer
version of the untracked directories (llgo, polly, lld, etc.) than
apple/stable/20190619.

Alex did the work to fix this, running:

    for repo in debuginfo-tests libclc libcxxabi \
                libunwind lld llgo openmp parallel-libs polly pstl
    do
      git rm -rf $repo > /dev/null
      latest_commit=$(git rev-list HEAD -n1 -- $repo)
      tree=$(git rev-parse origin/apple/stable/20190619:$repo)
      git read-tree --prefix=$repo $tree
    done

I've just simplified by making this a simple re-merge from
the merge-base with apple/stable/20190619 instead of an octopus from the
last commit to each directory above (which seems to unnecessarily
compilicate `git log --graph`).

In case anyone does care about those commits, here they are:

- 559c6e1: debuginfo-tests/
- 2abbe2f: libclc/
- 5a14c17: libcxxabi/
- d8bdb92: libunwind/
- d581dd5: lld/
- c0e6b8a: llgo/
- 673e547: openmp/
- 4a1b95b: parallel-libs/
- acbdd07: polly/
- 1b6d6e5: pstl/

Author: dexonsmith

debuginfo-tests/nrvo-string.cpp

@@ -7,8 +7,7 @@
 // RUN: %test_debuginfo %s %t.out
 //
 // PR34513
-volatile int sideeffect = 0;
-void __attribute__((noinline)) stop() { sideeffect++; }
+void __attribute__((noinline)) stop() {}
 
 struct string {
   string() {}
@@ -19,7 +18,7 @@ struct string {
 string get_string() {
   string unused;
   string result = 3;
-  // DEBUGGER: break 23
+  // DEBUGGER: break 22
   stop();
   return result;
 }
@@ -35,7 +34,7 @@ string2 get_string2() {
   some_function(result.i);
   // Test that the debugger can get the value of result after another
   // function is called.
-  // DEBUGGER: break 39
+  // DEBUGGER: break 38
   stop();
   return result;
 }

libcxxabi/CMakeLists.txt

@@ -43,9 +43,7 @@ include(CMakeDependentOption)
 include(HandleCompilerRT)
 
 # Define options.
-option(LIBCXXABI_ENABLE_EXCEPTIONS
-  "Provide support for exceptions in the runtime.
-  When disabled, libc++abi does not support stack unwinding and other exceptions-related features." ON)
+option(LIBCXXABI_ENABLE_EXCEPTIONS "Use exceptions." ON)
 option(LIBCXXABI_ENABLE_ASSERTIONS "Enable assertions independent of build mode." ON)
 option(LIBCXXABI_ENABLE_PEDANTIC "Compile with pedantic enabled." ON)
 option(LIBCXXABI_ENABLE_PIC "Build Position-Independent Code, even in static library" ON)

libcxxabi/cmake/Modules/HandleOutOfTreeLLVM.cmake

@@ -9,9 +9,6 @@ macro(find_llvm_parts)
     set(LLVM_PATH ${LLVM_PATH} CACHE PATH "Path to LLVM source tree")
     set(LLVM_MAIN_SRC_DIR ${LLVM_PATH})
     set(LLVM_CMAKE_PATH "${LLVM_PATH}/cmake/modules")
-    if (NOT IS_DIRECTORY "${LLVM_PATH}")
-      message(FATAL_ERROR "The provided LLVM_PATH (${LLVM_PATH}) is not a valid directory")
-    endif()
   elseif(LLVM_CONFIG_PATH)
     message(STATUS "Found LLVM_CONFIG_PATH as ${LLVM_CONFIG_PATH}")
     set(LIBCXXABI_USING_INSTALLED_LLVM 1)

libcxxabi/include/__cxxabi_config.h

@@ -71,8 +71,7 @@
 #define _LIBCXXABI_NO_CFI
 #endif
 
-// wasm32 follows the arm32 ABI convention of using 32-bit guard.
-#if defined(__arm__) || defined(__wasm32__)
+#if defined(__arm__)
 #  define _LIBCXXABI_GUARD_ABI_ARM
 #endif