driver: Support checking for rlimits via cmake (when bootstrapping)

[mgorny]

Summary

Add a cmake check for sys/resource.h and replace the has_include() check with its result, in order to make it possible to use rlimits when building with compilers not supporting has_include() -- i.e. when bootstrapping.

// Please also re-apply dfcd52eb1d8e5d322404b40414cb7331c7380a8c (llvm-config.h fix)

[vsk]

I don't see any issues with this patch, but I'm generally unfamiliar with the bootstrapping process and think Chris could give a better review.

(Also, as Richard pointed out earlier, including llvm-config.h might not be the right solution.)

[beanz]

Patch LGTM.

[mgorny]

Thanks for the review. Could you commit it for me, please? I don't have commit access.

CMakeLists.txt

 # we can include cmake files from this directory.
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 
 find_package(LibXml2 2.5.3 QUIET)
 if (LIBXML2_FOUND)
   set(CLANG_HAVE_LIBXML 1)
 endif()
 
+include(CheckIncludeFile)
+check_include_file(sys/resource.h CLANG_HAVE_RLIMITS)
+
 set(CLANG_RESOURCE_DIR "" CACHE STRING
   "Relative directory from the Clang binary to its resource files.")
 
 set(C_INCLUDE_DIRS "" CACHE STRING
   "Colon separated list of directories clang will search for headers.")
 
 set(GCC_INSTALL_PREFIX "" CACHE PATH "Directory where gcc is installed." )
 set(DEFAULT_SYSROOT "" CACHE PATH

include/clang/Config/config.h.cmake

 #define DEFAULT_SYSROOT "${DEFAULT_SYSROOT}"
 
 /* Directory where gcc is installed. */
 #define GCC_INSTALL_PREFIX "${GCC_INSTALL_PREFIX}"
 
 /* Define if we have libxml2 */
 #cmakedefine CLANG_HAVE_LIBXML ${CLANG_HAVE_LIBXML}
 
+/* Define if we have sys/resource.h (rlimits) */
+#cmakedefine CLANG_HAVE_RLIMITS ${CLANG_HAVE_RLIMITS}
+
 /* The LLVM product name and version */
 #define BACKEND_PACKAGE_STRING "${BACKEND_PACKAGE_STRING}"
 
 /* Linker version detected at compile time. */
 #cmakedefine HOST_LINK_VERSION "${HOST_LINK_VERSION}"
 
 /* pass --build-id to ld */
 #cmakedefine ENABLE_LINKER_BUILD_ID
 
 /* enable x86 relax relocations by default */
 #cmakedefine01 ENABLE_X86_RELAX_RELOCATIONS
 
 #endif

tools/driver/cc1_main.cpp

 // This is the entry point to the clang -cc1 functionality, which implements the
 // core compiler functionality along with a number of additional tools for
 // demonstration and testing purposes.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Option/Arg.h"
 #include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
+#include "clang/Config/config.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/Options.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/TextDiagnosticBuffer.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/FrontendTool/Utils.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Config/config.h"
 #include "llvm/LinkAllPasses.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptTable.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdio>
 
-#ifdef __has_include
-#if __has_include(<sys/resource.h>)
-#define HAVE_RLIMITS
+#ifdef CLANG_HAVE_RLIMITS
 #include <sys/resource.h>
 #endif
-#endif
 
 using namespace clang;
 using namespace llvm::opt;
 
 //===----------------------------------------------------------------------===//
 // Main driver
 //===----------------------------------------------------------------------===//
 

 }
 
 #ifdef LINK_POLLY_INTO_TOOLS
 namespace polly {
 void initializePollyPasses(llvm::PassRegistry &Registry);
 }
 #endif
 
-#ifdef HAVE_RLIMITS
+#ifdef CLANG_HAVE_RLIMITS
 // The amount of stack we think is "sufficient". If less than this much is
 // available, we may be unable to reach our template instantiation depth
 // limit and other similar limits.
 // FIXME: Unify this with the stack we request when spawning a thread to build
 // a module.
 static const int kSufficientStack = 8 << 20;
 
 #if defined(__linux__) && defined(__PIE__)