Workarounds for Saigo Clang 21

CMakeLists.txt

@@ -465,7 +465,6 @@ endif()
 include(DaemonNacl)
 if (NACL)
     add_library(srclibs-nacl-module EXCLUDE_FROM_ALL ${NACLLIST_MODULE})
-    set_target_properties(srclibs-nacl-module PROPERTIES POSITION_INDEPENDENT_CODE ${GAME_PIE} FOLDER "libs")
     set(LIBS_BASE ${LIBS_BASE} srclibs-nacl-module)
 else()
     add_library(srclibs-nacl-native EXCLUDE_FROM_ALL ${NACLLIST_NATIVE})

cmake/DaemonFlags.cmake

@@ -363,14 +363,12 @@ else()
 	endif()
 
 	if (NACL AND USE_NACL_SAIGO AND SAIGO_ARCH STREQUAL "arm")
-		# This should be set for every build type because build type flags
-		# are set after the other custom flags and then have the last word.
-		# DEBUG should already use -O0 anyway.
+		# Saigo produces broken arm builds when optimizing them.
 		# See: https://github.com/Unvanquished/Unvanquished/issues/3297
-		set_c_cxx_flag("-O0" DEBUG)
-		set_c_cxx_flag("-O0" RELEASE)
-		set_c_cxx_flag("-O0" RELWITHDEBINFO)
-		set_c_cxx_flag("-O0" MINSIZEREL)
+		# When setting this clang-specific option, we don't have to care
+		# about the ordering of -O options that may be introduced,
+		# all -O options added to the command line are ignored.
+		set_c_cxx_flag("-Xclang -disable-llvm-passes")
 	endif()
 
 	# Extra debug flags.
@@ -476,7 +474,16 @@ else()
 		# Don't set _FORTIFY_SOURCE in debug builds.
 	endif()
 
-	try_c_cxx_flag(FPIC "-fPIC")
+	if (NOT NACL)
+		# Saigo reports weird errors when building some cgame and sgame arm nexe with PIC:
+		# > error: Cannot represent a difference across sections
+		# > error: expected relocatable expression
+		# Google-built Saigo crashes when building amd64 cgame with PIC:
+		# > UNREACHABLE executed at llvm/lib/Target/X86/X86ISelLowering.cpp
+		# Self-built Saigo doesn't crash, maybe because assertions are disabled.
+		# PIC is not useful with NaCl under any circumstances, so we don't use PIC with NaCl.
+		try_c_cxx_flag(FPIC "-fPIC")
+	endif()
 
 	if (USE_HARDENING)
 		# PNaCl accepts the flags but does not define __stack_chk_guard and __stack_chk_fail.
@@ -491,7 +498,7 @@ else()
 		try_c_cxx_flag(FNO_STRICT_OVERFLOW "-fno-strict-overflow")
 		try_c_cxx_flag(WSTACK_PROTECTOR "-Wstack-protector")
 
-		if (NOT NACL OR (NACL AND GAME_PIE))
+		if (NOT NACL)
 			# The -pie flag requires -fPIC:
 			# > ld: error: relocation R_X86_64_64 cannot be used against local symbol; recompile with -fPIC
 			# This flag isn't used on macOS:

cmake/DaemonPlatform.cmake

@@ -40,14 +40,5 @@ else()
   message( FATAL_ERROR "Platform not supported" )
 endif()
 
-if (NACL AND USE_NACL_SAIGO)
-	# Saigo clang reports weird errors when building some cgame and sgame arm nexe with PIE.
-	# Saigo clang crashes when building amd64 cgame with PIE, sgame builds properly though.
-	set(GAME_PIE 0)
-else()
-	set(GAME_PIE 1)
-endif()
-
-
 include(DaemonArchitecture)
 include(DaemonCompiler)

src/shared/VMMain.cpp

@@ -34,6 +34,10 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "common/StackTrace.h"
 
+#if defined(__native_client__)
+#include <unistd.h>
+#endif
+
 IPC::Channel VM::rootChannel;
 
 #ifdef BUILD_VM_NATIVE_EXE