[llvm/cmake] Replace CMAKE_SOURCE_DIR with PROJECT_SOURCE_DIR

[sebastian-ne]

Summary

When adding llvm to a build with add_subdirectory, CMAKE_SOURCE_DIR
refers to the source directory of the parent project. We want to use
PROJECT_SOURCE_DIR instead.

[foad]

LGTM, thanks! In particular the fix to include/llvm/TargetParser/CMakeLists.txt fixes a build error when LLVM is included as a sub-project and the RISCV target is not being built. @fpetrogalli FYI

[fpetrogalli]

In D141521#4046690, @foad wrote:

LGTM, thanks! In particular the fix to include/llvm/TargetParser/CMakeLists.txt fixes a build error when LLVM is included as a sub-project and the RISCV target is not being built. @fpetrogalli FYI

Thank you for the fix!

llvm/cmake/modules/HandleLLVMOptions.cmake

elseif(MSVC)
     endif()
   else()
     message(FATAL_ERROR "LLVM_USE_SANITIZER is not supported on this platform.")
   endif()
   if (LLVM_USE_SANITIZE_COVERAGE)
     append("-fsanitize=fuzzer-no-link" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
   endif()
   if (LLVM_USE_SANITIZER MATCHES ".*Undefined.*")
-    set(IGNORELIST_FILE "${CMAKE_SOURCE_DIR}/utils/sanitizers/ubsan_ignorelist.txt")
+    set(IGNORELIST_FILE "${PROJECT_SOURCE_DIR}/utils/sanitizers/ubsan_ignorelist.txt")
     if (EXISTS "${IGNORELIST_FILE}")
       # Use this option name version since -fsanitize-ignorelist is only
       # accepted with clang 13.0 or newer.
       append("-fsanitize-blacklist=${IGNORELIST_FILE}"
              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     endif()
   endif()
 endif()

llvm/include/llvm/TargetParser/CMakeLists.txt

-set(LLVM_TARGET_DEFINITIONS ${CMAKE_SOURCE_DIR}/lib/Target/RISCV/RISCV.td)
-tablegen(LLVM RISCVTargetParserDef.inc -gen-riscv-target-def -I ${CMAKE_SOURCE_DIR}/lib/Target/RISCV/)
+set(LLVM_TARGET_DEFINITIONS ${PROJECT_SOURCE_DIR}/lib/Target/RISCV/RISCV.td)
+tablegen(LLVM RISCVTargetParserDef.inc -gen-riscv-target-def -I ${PROJECT_SOURCE_DIR}/lib/Target/RISCV/)
 add_public_tablegen_target(RISCVTargetParserTableGen)
-

llvm/unittests/Target/PowerPC/CMakeLists.txt

 include_directories(
-  ${CMAKE_SOURCE_DIR}/lib/Target/PowerPC
-  ${CMAKE_BINARY_DIR}/lib/Target/PowerPC
+  ${PROJECT_SOURCE_DIR}/lib/Target/PowerPC
+  ${PROJECT_BINARY_DIR}/lib/Target/PowerPC
   )
 
 set(LLVM_LINK_COMPONENTS
   MC
   Support
   Target
   TargetParser
   PowerPCCodeGen

llvm/unittests/Target/WebAssembly/CMakeLists.txt

 include_directories(
-  ${CMAKE_SOURCE_DIR}/lib/Target/WebAssembly
-  ${CMAKE_BINARY_DIR}/lib/Target/WebAssembly
+  ${PROJECT_SOURCE_DIR}/lib/Target/WebAssembly
+  ${PROJECT_BINARY_DIR}/lib/Target/WebAssembly
   )
 
 set(LLVM_LINK_COMPONENTS
   CodeGen
   Core
   MC
   MIRParser
   TargetParser

llvm/unittests/Target/X86/CMakeLists.txt

 include_directories(
-  ${CMAKE_SOURCE_DIR}/lib/Target/X86
-  ${CMAKE_BINARY_DIR}/lib/Target/X86
+  ${PROJECT_SOURCE_DIR}/lib/Target/X86
+  ${PROJECT_BINARY_DIR}/lib/Target/X86
   )
 
 set(LLVM_LINK_COMPONENTS
   Analysis
   CodeGen
   Core
   MC
   MIRParser