CMake: New user-settable variable LLVM_TARGET_ARCH useful when

cross-compiling.

Patch by Xerxes Rånby!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81722 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -70,6 +70,9 @@ else( MSVC )
     CACHE STRING "Semicolon-separated list of targets to build, or \"all\".")
 endif( MSVC )
 
+set(LLVM_TARGET_ARCH "host"
+  CACHE STRING "Set target to use for LLVM JIT or use \"host\" for automatic detection.")
+
 option(LLVM_ENABLE_THREADS "Use threads if available." ON)
 
 if( uppercase_CMAKE_BUILD_TYPE STREQUAL "RELEASE" )

cmake/config-ix.cmake

@@ -92,13 +92,18 @@ get_target_triple(LLVM_HOSTTRIPLE)
 message(STATUS "LLVM_HOSTTRIPLE: ${LLVM_HOSTTRIPLE}")
 
 # Determine the native architecture.
-# FIXME: this will have to change for cross-compiling.
-string(REGEX MATCH "^[^-]*" LLVM_NATIVE_ARCH ${LLVM_HOSTTRIPLE})
+string(TOLOWER "${LLVM_TARGET_ARCH}" LLVM_NATIVE_ARCH)
+if( LLVM_NATIVE_ARCH STREQUAL "host" )
+  string(REGEX MATCH "^[^-]*" LLVM_NATIVE_ARCH ${LLVM_HOSTTRIPLE})
+endif ()
+
 if (LLVM_NATIVE_ARCH MATCHES "i[2-6]86")
   set(LLVM_NATIVE_ARCH X86)
-elseif (LLVM_NATIVE_ARCH STREQUAL amd64)
+elseif (LLVM_NATIVE_ARCH STREQUAL "x86")
+  set(LLVM_NATIVE_ARCH X86)
+elseif (LLVM_NATIVE_ARCH STREQUAL "amd64")
   set(LLVM_NATIVE_ARCH X86)
-elseif (LLVM_NATIVE_ARCH STREQUAL x86_64)
+elseif (LLVM_NATIVE_ARCH STREQUAL "x86_64")
   set(LLVM_NATIVE_ARCH X86)
 elseif (LLVM_NATIVE_ARCH MATCHES "sparc")
   set(LLVM_NATIVE_ARCH Sparc)

docs/CMake.html

@@ -273,6 +273,13 @@
   option is available only on some 64-bits unix systems. Defaults to
   OFF.</dd>
 
+  <dt><b>LLVM_TARGET_ARCH</b>:STRING</dt>
+  <dd>LLVM target to use for native code generation. This is required
+    for JIT generation. It defaults to "host", meaning that it shall
+    pick the architecture of the machine where LLVM is being built. If
+    you are cross-compiling, set it to the target architecture
+    name.</dd>
+
   <dt><b>LLVM_TABLEGEN</b>:STRING</dt>
   <dd>Full path to a native TableGen executable (usually
     named <i>tblgen</i>). This is intented for cross-compiling: if the
@@ -311,6 +318,9 @@
     <a href="http://www.vtk.org/Wiki/CMake_Cross_Compiling#Information_how_to_set_up_various_cross_compiling_toolchains">this
     section</a> for a quick solution.</p>
 
+<p>Also see the <a href="#llvmvars">LLVM-specific variables</a>
+  section for variables used when cross-compiling.</p>
+
 </div>
 
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