[CMake] Support cross-compiling with multi-stage builds

When using multi-stage builds, we would like support cross-compilation.
Example is 2-stage build when the first stage is compiled for host while
the second stage is compiled for the target.

Normally, the second stage would be also used for compiling runtimes,
but that's not possible when cross-compiling, so we use the first stage
compiler instead. However, we still want to use the second stage paths.
To do so, we set the -resource-dir of the first stage compiler to point
to the resource directory of the second stage.

We also need compiler tools that support the target architecture. These
tools are not guaranteed to be present on the host, but in case of
multi-stage build, we can build these tools in the first stage.

Differential Revision: https://reviews.llvm.org/D54461

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@347025 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0a38688066ab106b3dc67371d66195503c71ea97..1482b17abcc219180015fa93d0303e51d9e18188 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -599,8 +599,8 @@ if (CLANG_ENABLE_BOOTSTRAP)
       if(NOT BOOTSTRAP_LLVM_ENABLE_LLD AND LLVM_BINUTILS_INCDIR)
         add_dependencies(clang-bootstrap-deps LLVMgold)
       endif()
-      set(LTO_AR -DCMAKE_AR=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ar)
-      set(LTO_RANLIB -DCMAKE_RANLIB=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ranlib)
+      set(${CLANG_STAGE}_AR -DCMAKE_AR=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ar)
+      set(${CLANG_STAGE}_RANLIB -DCMAKE_RANLIB=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ranlib)
     endif()
   endif()
 
@@ -666,6 +666,26 @@ if (CLANG_ENABLE_BOOTSTRAP)
     -DCMAKE_ASM_COMPILER=${LLVM_RUNTIME_OUTPUT_INTDIR}/${C_COMPILER}
     -DCMAKE_ASM_COMPILER_ID=Clang)
 
+  if(BOOTSTRAP_CMAKE_SYSTEM_NAME)
+    set(${CLANG_STAGE}_CONFIG -DLLVM_CONFIG_PATH=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-config)
+    set(${CLANG_STAGE}_TABLEGEN
+      -DLLVM_TABLEGEN=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-tblgen
+      -DCLANG_TABLEGEN=${LLVM_RUNTIME_OUTPUT_INTDIR}/clang-tblgen)
+    if(BOOTSTRAP_CMAKE_SYSTEM_NAME STREQUAL "Linux")
+      if(BOOTSTRAP_LLVM_ENABLE_LLD)
+        set(${CLANG_STAGE}_LINKER -DCMAKE_LINKER=${LLVM_RUNTIME_OUTPUT_INTDIR}/ld.lld)
+      endif()
+      if(NOT BOOTSTRAP_LLVM_ENABLE_LTO)
+        add_dependencies(clang-bootstrap-deps llvm-ar llvm-ranlib)
+        set(${CLANG_STAGE}_AR -DCMAKE_AR=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ar)
+        set(${CLANG_STAGE}_RANLIB -DCMAKE_RANLIB=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ranlib)
+      endif()
+      add_dependencies(clang-bootstrap-deps llvm-objcopy llvm-strip)
+      set(${CLANG_STAGE}_OBJCOPY -DCMAKE_OBJCOPY=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-objcopy)
+      set(${CLANG_STAGE}_STRIP -DCMAKE_STRIP=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-strip)
+    endif()
+  endif()
+
   if(BOOTSTRAP_LLVM_BUILD_INSTRUMENTED)
     add_dependencies(clang-bootstrap-deps llvm-profdata)
     set(PGO_OPT -DLLVM_PROFDATA=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-profdata)
@@ -734,7 +754,14 @@ if (CLANG_ENABLE_BOOTSTRAP)
                 ${PASSTHROUGH_VARIABLES}
                  -DCLANG_STAGE=${NEXT_CLANG_STAGE}
                 ${COMPILER_OPTIONS}
-                ${LTO_LIBRARY} ${LTO_AR} ${LTO_RANLIB} ${verbose} ${PGO_OPT}
+                ${${CLANG_STAGE}_CONFIG}
+                ${${CLANG_STAGE}_TABLEGEN}
+                ${LTO_LIBRARY} ${verbose} ${PGO_OPT}
+                ${${CLANG_STAGE}_LINKER}
+                ${${CLANG_STAGE}_AR}
+                ${${CLANG_STAGE}_RANLIB}
+                ${${CLANG_STAGE}_OBJCOPY}
+                ${${CLANG_STAGE}_STRIP}
     INSTALL_COMMAND ""
     STEP_TARGETS configure build
     USES_TERMINAL_CONFIGURE 1