gn build: Fix build when not building the native target.

Differential Revision: https://reviews.llvm.org/D127068

Author: pcc

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -329,13 +329,6 @@ write_cmake_config("llvm-config") {
     "LLVM_HAVE_TF_API=",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
     "LLVM_NATIVE_ARCH=$native_target",
-    "LLVM_NATIVE_ASMPARSER=1",
-    "LLVM_NATIVE_ASMPRINTER=1",
-    "LLVM_NATIVE_DISASSEMBLER=1",
-    "LLVM_NATIVE_TARGET=1",
-    "LLVM_NATIVE_TARGETINFO=1",
-    "LLVM_NATIVE_TARGETMC=1",
-    "LLVM_NATIVE_TARGETMCA=1",
     "LLVM_UNREACHABLE_OPTIMIZE=1",
     "LLVM_USE_INTEL_JITEVENTS=",
     "LLVM_USE_OPROFILE=",
@@ -347,6 +340,28 @@ write_cmake_config("llvm-config") {
     "PACKAGE_VERSION=${llvm_version}git",
   ]
 
+  if (llvm_build_native) {
+    values += [
+      "LLVM_NATIVE_ASMPARSER=1",
+      "LLVM_NATIVE_ASMPRINTER=1",
+      "LLVM_NATIVE_DISASSEMBLER=1",
+      "LLVM_NATIVE_TARGET=1",
+      "LLVM_NATIVE_TARGETINFO=1",
+      "LLVM_NATIVE_TARGETMC=1",
+      "LLVM_NATIVE_TARGETMCA=1",
+    ]
+  } else {
+    values += [
+      "LLVM_NATIVE_ASMPARSER=",
+      "LLVM_NATIVE_ASMPRINTER=",
+      "LLVM_NATIVE_DISASSEMBLER=",
+      "LLVM_NATIVE_TARGET=",
+      "LLVM_NATIVE_TARGETINFO=",
+      "LLVM_NATIVE_TARGETMC=",
+      "LLVM_NATIVE_TARGETMCA=",
+    ]
+  }
+
   if (current_os == "win") {
     values += [
       "HAVE_SYSEXITS_H=",

llvm/utils/gn/secondary/llvm/lib/Target/targets.gni

@@ -26,18 +26,21 @@ llvm_all_targets = [
   "X86",
 ]
 
+# FIXME: This should be based off target_cpu once cross compiles work.
+if (host_cpu == "arm64") {
+  native_target = "AArch64"
+} else if (host_cpu == "arm") {
+  native_target = "ARM"
+} else if (host_cpu == "ppc" || host_cpu == "ppc64") {
+  native_target = "PowerPC"
+} else if (host_cpu == "x86" || host_cpu == "x64") {
+  native_target = "X86"
+} else {
+  assert(false, "add your host_cpu above")
+}
+
 if (llvm_targets_to_build == "host") {
-  if (host_cpu == "arm64") {
-    llvm_targets_to_build = [ "AArch64" ]
-  } else if (host_cpu == "arm") {
-    llvm_targets_to_build = [ "ARM" ]
-  } else if (host_cpu == "ppc" || host_cpu == "ppc64") {
-    llvm_targets_to_build = [ "PowerPC" ]
-  } else if (host_cpu == "x86" || host_cpu == "x64") {
-    llvm_targets_to_build = [ "X86" ]
-  } else {
-    assert(false, "add your host_cpu above")
-  }
+  llvm_targets_to_build = [ native_target ]
 } else if (llvm_targets_to_build == "all") {
   llvm_targets_to_build = llvm_all_targets
 }
@@ -54,7 +57,11 @@ llvm_build_PowerPC = false
 llvm_build_SystemZ = false
 llvm_build_WebAssembly = false
 llvm_build_X86 = false
+llvm_build_native = false
 foreach(target, llvm_targets_to_build) {
+  if (target == native_target) {
+    llvm_build_native = true
+  }
   if (target == "AArch64") {
     llvm_build_AArch64 = true
   } else if (target == "AMDGPU") {
@@ -87,19 +94,6 @@ foreach(target, llvm_targets_to_build) {
   }
 }
 
-# FIXME: This should be based off target_cpu once cross compiles work.
-if (host_cpu == "arm64") {
-  native_target = "AArch64"
-} else if (host_cpu == "arm") {
-  native_target = "ARM"
-} else if (host_cpu == "ppc" || host_cpu == "ppc64") {
-  native_target = "PowerPC"
-} else if (host_cpu == "x86" || host_cpu == "x64") {
-  native_target = "X86"
-} else {
-  assert(false, "Unsuppored host_cpu '$host_cpu'.")
-}
-
 supported_android_toolchains = []
 
 if (android_ndk_path != "") {