CMake: Reorder PIE checks, fix bracket limit for Clang

The default limit for recent versions of Clang is 256 which is less than the
number of syscalls in our syscall tables (around 340). This change increases
this limit to an arbitrary 768.

PiperOrigin-RevId: 429258387
Change-Id: I4927eee78edc8aaa2a758b29811d02326e5aa953

CMakeLists.txt

@@ -14,6 +14,10 @@
 
 cmake_minimum_required(VERSION 3.13..3.22)
 
+if(POLICY CMP0083)
+  cmake_policy(SET CMP0083 NEW)
+endif()
+
 project(SandboxedAPI C CXX ASM)
 
 # TODO(cblichmann): Enable for Android once support lands
@@ -44,6 +48,17 @@ endif()
 
 include(CheckCXXCompilerFlag)
 
+# Allow the header generator to auto-configure include paths
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+set(CMAKE_SKIP_BUILD_RPATH ON)
+
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.14)
+  include(CheckPIESupported)
+  check_pie_supported()
+  set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+endif()
+
 # SAPI CMake modules, order matters
 list(APPEND CMAKE_MODULE_PATH "${SAPI_SOURCE_DIR}/cmake"
                               "${SAPI_SOURCE_DIR}/cmake/modules")
@@ -53,17 +68,6 @@ include(SapiUtil)
 include(SapiBuildDefs)
 include(GNUInstallDirs)
 
-# Allow the header generator to auto-configure include paths
-set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-
-set(CMAKE_SKIP_BUILD_RPATH ON)
-
-if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.14)
-  cmake_policy(SET CMP0083 NEW)
-  include(CheckPIESupported)
-  check_pie_supported()
-endif()
-
 if(SAPI_HARDENED_SOURCE)
   add_compile_options(-fstack-protector -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2)
   add_link_options(-Wl,-z,relro -Wl,-z,now)
@@ -100,12 +104,21 @@ target_include_directories(sapi_base PUBLIC
   "${SAPI_SOURCE_DIR}"
   "${Protobuf_INCLUDE_DIR}"
 )
-target_compile_options(sapi_base PUBLIC -fno-exceptions)
+target_compile_options(sapi_base PUBLIC
+  -fno-exceptions
+)
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  target_compile_options(sapi_base PUBLIC
+    # The syscall tables in sandbox2/syscall_defs.cc are `std::array`s using
+    # CTAD and have more entries than the default limit of 256.
+    -fbracket-depth=768
+  )
+endif()
 set(_sapi_check_no_deprecated
   -Wno-deprecated SAPI_HAS_W_NO_DEPRECATED
 )
-# For sandbox2/util.cc's CloneAndJump()
 set(_sapi_check_frame_larger_than
+  # For sandbox2/util.cc's CloneAndJump()
   -Wframe-larger-than=40960 SAPI_HAS_W_FRAME_LARGER_THAN
 )
 set(_sapi_check_no_deprecated_declarations