Update the default compilation options

Recent versions of Clang support `-fptrauth-elf-got` as a compiler
driver option, thus do not use `-Xclang ...` anymore. Passing this
option through the Clang driver makes it possible to override it
by `-fno-ptrauth-elf-got` without modifying the *.cfg files.

Additionally, enable more assertions by default:
* Build LLVM with LLVM_ENABLE_ASSERTIONS
* Check MachineInstr produced by the backend

Author: atrosinenko

cmake/llvm.cmake

@@ -1,5 +1,5 @@
 set(CMAKE_BUILD_TYPE       "Release" CACHE STRING "" FORCE)
-set(LLVM_ENABLE_ASSERTIONS FALSE     CACHE BOOL   "" FORCE)
+set(LLVM_ENABLE_ASSERTIONS TRUE      CACHE BOOL   "" FORCE)
 set(LLVM_CCACHE_BUILD      TRUE      CACHE BOOL   "" FORCE)
 set(LLVM_LINK_LLVM_DYLIB   TRUE      CACHE BOOL   "" FORCE)
 set(CLANG_LINK_CLANG_DYLIB TRUE      CACHE BOOL   "" FORCE)

config

@@ -11,7 +11,8 @@ LLVM_SHA=a832a5222e489298337fbb5876f8dcaf072c5cca
 MUSL_SHA=b37ee52aff13880884a7afa8c5161a4f4f7e0236
 
 # Extra flags to write to Clang config files as the defaults.
-EXTRA_FLAGS_PAUTHTEST="-Xclang -fptrauth-elf-got"
+EXTRA_FLAGS_COMMON="-mllvm -verify-machineinstrs"
+EXTRA_FLAGS_PAUTHTEST="-fptrauth-elf-got"
 EXTRA_FLAGS_MUSL=""
 
 ### Other variables ###

scripts/build-all.sh

@@ -16,10 +16,12 @@ set +x
 write_clang_config_files() {
   cat > "$INSTALL_DIR/bin/aarch64-unknown-linux-pauthtest.cfg" <<EOF
 --sysroot <CFGDIR>/../aarch64-linux-pauthtest
+$EXTRA_FLAGS_COMMON
 $EXTRA_FLAGS_PAUTHTEST
 EOF
   cat > "$INSTALL_DIR/bin/aarch64-unknown-linux-musl.cfg" <<EOF
 --sysroot <CFGDIR>/../aarch64-linux-musl
+$EXTRA_FLAGS_COMMON
 $EXTRA_FLAGS_MUSL
 EOF
 }