[compiler-rt] Move crt into builtins

On Linux crt is typically use in combination with builtins. In the Clang
driver the use of builtins and crt is controlled by the --rtlib option.
Both builtins and crt also have similar build requirements where they
need to be built before any other runtimes and must avoid dependencies.
We also want builtins and crt these to be buildable separately from the
rest of compiler-rt for bootstrapping purposes. Given how simple crt is,
rather than maintaining a separate directory with its own separate build
setup, it's more efficient to just move crt into builtins. We still use
separate CMake option to control whether to built crt same as before.

This is an alternative to D89492 and D136664.

Differential Revision: https://reviews.llvm.org/D153989

compiler-rt/CMakeLists.txt

@@ -39,10 +39,6 @@ option(COMPILER_RT_BUILD_BUILTINS "Build builtins" ON)
 mark_as_advanced(COMPILER_RT_BUILD_BUILTINS)
 option(COMPILER_RT_DISABLE_AARCH64_FMV "Disable AArch64 Function Multi Versioning support" OFF)
 mark_as_advanced(COMPILER_RT_DISABLE_AARCH64_FMV)
-option(COMPILER_RT_BUILD_CRT "Build crtbegin.o/crtend.o" ON)
-mark_as_advanced(COMPILER_RT_BUILD_CRT)
-option(COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY "Use eh_frame in crtbegin.o/crtend.o" ON)
-mark_as_advanced(COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY)
 option(COMPILER_RT_BUILD_SANITIZERS "Build sanitizers" ON)
 mark_as_advanced(COMPILER_RT_BUILD_SANITIZERS)
 option(COMPILER_RT_BUILD_XRAY "Build xray" ON)

compiler-rt/cmake/builtin-config-ix.cmake

@@ -13,6 +13,11 @@ builtin_check_c_compiler_flag(-fvisibility=hidden   COMPILER_RT_HAS_VISIBILITY_H
 builtin_check_c_compiler_flag(-fomit-frame-pointer  COMPILER_RT_HAS_OMIT_FRAME_POINTER_FLAG)
 builtin_check_c_compiler_flag(-ffreestanding        COMPILER_RT_HAS_FFREESTANDING_FLAG)
 builtin_check_c_compiler_flag(-fxray-instrument     COMPILER_RT_HAS_XRAY_COMPILER_FLAG)
+builtin_check_c_compiler_flag(-fno-lto              COMPILER_RT_HAS_FNO_LTO_FLAG)
+builtin_check_c_compiler_flag(-fno-profile-generate COMPILER_RT_HAS_FNO_PROFILE_GENERATE_FLAG)
+builtin_check_c_compiler_flag(-fno-profile-instr-generate COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
+builtin_check_c_compiler_flag(-fno-profile-instr-use COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
+builtin_check_c_compiler_flag(-Wno-pedantic         COMPILER_RT_HAS_WNO_PEDANTIC)
 
 builtin_check_c_compiler_source(COMPILER_RT_HAS_ATOMIC_KEYWORD
 "
@@ -28,6 +33,12 @@ asm(\".arch armv8-a+lse\");
 asm(\"cas w0, w1, [x2]\");
 ")
 
+if(ANDROID)
+  set(OS_NAME "Android")
+else()
+  set(OS_NAME "${CMAKE_SYSTEM_NAME}")
+endif()
+
 set(ARM64 aarch64)
 set(ARM32 arm armhf armv4t armv5te armv6 armv6m armv7m armv7em armv7 armv7s armv7k armv8m.base armv8m.main armv8.1m.main)
 set(AVR avr)
@@ -214,4 +225,10 @@ else()
     ${ALL_BUILTIN_SUPPORTED_ARCH})
 endif()
 
+if (OS_NAME MATCHES "Linux" AND NOT LLVM_USE_SANITIZER)
+  set(COMPILER_RT_HAS_CRT TRUE)
+else()
+  set(COMPILER_RT_HAS_CRT FALSE)
+endif()
+
 message(STATUS "Builtin supported architectures: ${BUILTIN_SUPPORTED_ARCH}")

compiler-rt/lib/CMakeLists.txt

@@ -17,10 +17,6 @@ if(COMPILER_RT_BUILD_BUILTINS)
   add_subdirectory(builtins)
 endif()
 
-if(COMPILER_RT_BUILD_CRT)
-  add_subdirectory(crt)
-endif()
-
 function(compiler_rt_build_runtime runtime)
   string(TOUPPER ${runtime} runtime_uppercase)
   if(COMPILER_RT_HAS_${runtime_uppercase})

compiler-rt/lib/builtins/CMakeLists.txt

@@ -51,12 +51,9 @@ if (COMPILER_RT_STANDALONE_BUILD)
 endif()
 
 include(builtin-config-ix)
+include(CMakeDependentOption)
 include(CMakePushCheckState)
 
-if(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
-  include(CompilerRTAIXUtils)
-endif()
-
 option(COMPILER_RT_BUILTINS_HIDE_SYMBOLS
   "Do not export any symbols from the static library." ON)
 
@@ -690,7 +687,7 @@ set(powerpc64_SOURCES
   ${GENERIC_SOURCES}
 )
 # These routines require __int128, which isn't supported on AIX.
-if (NOT ${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+if (NOT OS_NAME MATCHES "AIX")
   set(powerpc64_SOURCES
     ppc/floattitf.c
     ppc/fixtfti.c
@@ -855,14 +852,17 @@ else ()
   endforeach ()
 endif ()
 
+add_dependencies(compiler-rt builtins)
+
 option(COMPILER_RT_BUILD_STANDALONE_LIBATOMIC
   "Build standalone shared atomic library."
   OFF)
 
 if(COMPILER_RT_BUILD_STANDALONE_LIBATOMIC)
   add_custom_target(builtins-standalone-atomic)
   set(BUILTIN_TYPE SHARED)
-  if(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+  if(OS_NAME MATCHES "AIX")
+    include(CompilerRTAIXUtils)
     if(NOT COMPILER_RT_LIBATOMIC_LINK_FLAGS)
       get_aix_libatomic_default_link_flags(COMPILER_RT_LIBATOMIC_LINK_FLAGS
         "${CMAKE_CURRENT_SOURCE_DIR}/ppc/atomic.exp")
@@ -887,12 +887,48 @@ if(COMPILER_RT_BUILD_STANDALONE_LIBATOMIC)
   # FIXME: On AIX, we have to archive built shared libraries into a static
   # archive, i.e., libatomic.a. Once cmake adds support of such usage for AIX,
   # this ad-hoc part can be removed.
-  if(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+  if(OS_NAME MATCHES "AIX")
     archive_aix_libatomic(clang_rt.atomic libatomic
                           ARCHS ${BUILTIN_SUPPORTED_ARCH}
                           PARENT_TARGET builtins-standalone-atomic)
   endif()
   add_dependencies(compiler-rt builtins-standalone-atomic)
 endif()
 
-add_dependencies(compiler-rt builtins)
+cmake_dependent_option(COMPILER_RT_BUILD_CRT "Build crtbegin.o/crtend.o" ON "COMPILER_RT_HAS_CRT" OFF)
+
+if(COMPILER_RT_BUILD_CRT)
+  add_compiler_rt_component(crt)
+
+  option(COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY "Use eh_frame in crtbegin.o/crtend.o" ON)
+
+  include(CheckSectionExists)
+  check_section_exists(".init_array" COMPILER_RT_HAS_INITFINI_ARRAY
+    SOURCE "volatile int x;\n__attribute__((constructor)) void f(void) {x = 0;}\nint main(void) { return 0; }\n")
+
+  append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 CRT_CFLAGS)
+  append_list_if(COMPILER_RT_HAS_INITFINI_ARRAY -DCRT_HAS_INITFINI_ARRAY CRT_CFLAGS)
+  append_list_if(COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY -DEH_USE_FRAME_REGISTRY CRT_CFLAGS)
+  append_list_if(COMPILER_RT_HAS_FPIC_FLAG -fPIC CRT_CFLAGS)
+  append_list_if(COMPILER_RT_HAS_WNO_PEDANTIC -Wno-pedantic CRT_CFLAGS)
+  if (COMPILER_RT_HAS_FCF_PROTECTION_FLAG)
+    append_list_if(COMPILER_RT_ENABLE_CET -fcf-protection=full CRT_CFLAGS)
+  endif()
+
+  foreach(arch ${BUILTIN_SUPPORTED_ARCH})
+    add_compiler_rt_runtime(clang_rt.crtbegin
+      OBJECT
+      ARCHS ${arch}
+      SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/crtbegin.c
+      CFLAGS ${CRT_CFLAGS}
+      PARENT_TARGET crt)
+    add_compiler_rt_runtime(clang_rt.crtend
+      OBJECT
+      ARCHS ${arch}
+      SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/crtend.c
+      CFLAGS ${CRT_CFLAGS}
+      PARENT_TARGET crt)
+  endforeach()
+
+  add_dependencies(compiler-rt crt)
+endif()

compiler-rt/test/CMakeLists.txt

@@ -103,9 +103,6 @@ if(COMPILER_RT_CAN_EXECUTE_TESTS)
   if(COMPILER_RT_BUILD_ORC)
     compiler_rt_Test_runtime(orc)
   endif()
-  if(COMPILER_RT_BUILD_CRT)
-    add_subdirectory(crt)
-  endif()
   # ShadowCallStack does not yet provide a runtime with compiler-rt, the tests
   # include their own minimal runtime
   add_subdirectory(shadowcallstack)

compiler-rt/test/builtins/CMakeLists.txt

@@ -13,6 +13,10 @@ configure_lit_site_cfg(
 
 include(builtin-config-ix)
 
+if (COMPILER_RT_HAS_CRT)
+  list(APPEND BUILTINS_TEST_DEPS crt)
+endif()
+
 # Indicate if this is an MSVC environment.
 pythonize_bool(MSVC)
 

compiler-rt/test/crt/ctor_dtor.c → compiler-rt/test/builtins/Unit/ctor_dtor.c

@@ -1,3 +1,5 @@
+// REQUIRES: linux
+
 // RUN: %clang -fno-use-init-array -g -c %s -o %t.o
 // RUN: %clang -o %t -no-pie -nostdlib %crt1 %crti %crtbegin %t.o -lc %libgcc %crtend %crtn
 // RUN: %run %t 2>&1 | FileCheck %s

compiler-rt/test/crt/dso_handle.cpp → compiler-rt/test/builtins/Unit/dso_handle.cpp

@@ -1,5 +1,7 @@
-// RUN: %clangxx -g -DCRT_SHARED -c %s -fPIC -o %tshared.o
-// RUN: %clangxx -g -c %s -fPIC -o %t.o
+// REQUIRES: linux
+
+// RUN: %clangxx -g -fno-exceptions -DCRT_SHARED -c %s -fPIC -o %tshared.o
+// RUN: %clangxx -g -fno-exceptions -c %s -fPIC -o %t.o
 // RUN: %clangxx -g -shared -o %t.so -nostdlib %crti %crtbegin %tshared.o %libstdcxx -lc -lm %libgcc %crtend %crtn
 // RUN: %clangxx -g -o %t -fno-pic -no-pie -nostdlib %crt1 %crti %crtbegin %t.o %libstdcxx -lc -lm %libgcc %t.so %crtend %crtn
 // RUN: %run %t 2>&1 | FileCheck %s

compiler-rt/test/builtins/Unit/lit.cfg.py

@@ -2,6 +2,8 @@
 
 import os
 import platform
+import shlex
+import subprocess
 
 import lit.formats
 
@@ -28,6 +30,40 @@ def get_required_attr(config, attr_name):
     return attr_value
 
 
+def get_library_path(file):
+    cmd = subprocess.Popen(
+        [config.clang.strip(), "-print-file-name=%s" % file]
+        + shlex.split(config.target_cflags),
+        stdout=subprocess.PIPE,
+        env=config.environment,
+        universal_newlines=True,
+    )
+    if not cmd.stdout:
+        lit_config.fatal("Couldn't find the library path for '%s'" % file)
+    dir = cmd.stdout.read().strip()
+    if sys.platform in ["win32"] and execute_external:
+        # Don't pass dosish path separator to msys bash.exe.
+        dir = dir.replace("\\", "/")
+    return dir
+
+
+def get_libgcc_file_name():
+    cmd = subprocess.Popen(
+        [config.clang.strip(), "-print-libgcc-file-name"]
+        + shlex.split(config.target_cflags),
+        stdout=subprocess.PIPE,
+        env=config.environment,
+        universal_newlines=True,
+    )
+    if not cmd.stdout:
+        lit_config.fatal("Couldn't find the library path for '%s'" % file)
+    dir = cmd.stdout.read().strip()
+    if sys.platform in ["win32"] and execute_external:
+        # Don't pass dosish path separator to msys bash.exe.
+        dir = dir.replace("\\", "/")
+    return dir
+
+
 # Setup config name.
 config.name = "Builtins" + config.name_suffix
 
@@ -70,6 +106,27 @@ def get_required_attr(config, attr_name):
         base_lib = base_lib.replace("\\", "/")
     config.substitutions.append(("%librt ", base_lib + " -lc -lm "))
 
+    if config.host_os == "Linux":
+        base_obj = os.path.join(
+            config.compiler_rt_libdir, "clang_rt.%%s%s.o" % config.target_suffix
+        )
+        if sys.platform in ["win32"] and execute_external:
+            # Don't pass dosish path separator to msys bash.exe.
+            base_obj = base_obj.replace("\\", "/")
+
+        config.substitutions.append(("%crtbegin", base_obj % "crtbegin"))
+        config.substitutions.append(("%crtend", base_obj % "crtend"))
+
+        config.substitutions.append(("%crt1", get_library_path("crt1.o")))
+        config.substitutions.append(("%crti", get_library_path("crti.o")))
+        config.substitutions.append(("%crtn", get_library_path("crtn.o")))
+
+        config.substitutions.append(("%libgcc", get_libgcc_file_name()))
+
+        config.substitutions.append(
+            ("%libstdcxx", "-l" + config.sanitizer_cxx_lib.lstrip("lib"))
+        )
+
 builtins_source_dir = os.path.join(
     get_required_attr(config, "compiler_rt_src_root"), "lib", "builtins"
 )

compiler-rt/test/builtins/Unit/lit.site.cfg.py.in

@@ -4,6 +4,7 @@ config.name_suffix = "@BUILTINS_TEST_CONFIG_SUFFIX@"
 config.builtins_lit_source_dir = "@BUILTINS_LIT_SOURCE_DIR@/Unit"
 config.target_cflags = "@BUILTINS_TEST_TARGET_CFLAGS@"
 config.target_arch = "@BUILTINS_TEST_TARGET_ARCH@"
+config.sanitizer_cxx_lib = "@SANITIZER_TEST_CXX_LIBNAME@"
 config.is_msvc = @MSVC_PYBOOL@
 config.builtins_is_msvc = @BUILTINS_IS_MSVC_PYBOOL@
 config.builtins_lit_source_features = "@BUILTINS_LIT_SOURCE_FEATURES@"