From 4a1d40cba032b81e8301cbf3d0227545d0856307 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Wed, 21 Apr 2021 12:40:39 +0300
Subject: [PATCH] [llvm-rc] Try to fix the Preprocessor/llvm-rc.rc test on non
 arm/x86 architectures

When llvm-rc invokes clang for preprocessing, it uses a target
triple derived from the default target. The test verifies that
e.g. _WIN32 is defined when preprocessing.

If running clang with e.g. -target ppc64le-windows-msvc, that
particular arch/OS combination isn't hooked up, so _WIN32 doesn't
get defined in that configuration. Therefore, the preprocessing
test fails.

Instead make llvm-rc inspect the architecture of the default target.
If it's one of the known supported architectures, use it as such,
otherwise set a default one (x86_64). (Clang can run preprocessing
with an x86_64 target triple, even if the x86 backend isn't
enabled.)

Also remove superfluous llvm:: specifications on enums in llvm-rc.cpp.
---
 tools/llvm-rc/llvm-rc.cpp | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/tools/llvm-rc/llvm-rc.cpp b/tools/llvm-rc/llvm-rc.cpp
index ab5ecb8fa3f..b61fba78ad0 100644
--- a/tools/llvm-rc/llvm-rc.cpp
+++ b/tools/llvm-rc/llvm-rc.cpp
@@ -114,10 +114,25 @@ ErrorOr<std::string> findClang(const char *Argv0) {
 
 std::string getClangClTriple() {
   Triple T(sys::getDefaultTargetTriple());
-  T.setOS(llvm::Triple::Win32);
-  T.setVendor(llvm::Triple::PC);
-  T.setEnvironment(llvm::Triple::MSVC);
-  T.setObjectFormat(llvm::Triple::COFF);
+  switch (T.getArch()) {
+  case Triple::x86:
+  case Triple::x86_64:
+  case Triple::arm:
+  case Triple::thumb:
+  case Triple::aarch64:
+    // These work properly with the clang driver, setting the expected
+    // defines such as _WIN32 etc.
+    break;
+  default:
+    // Other archs aren't set up for use with windows as target OS, (clang
+    // doesn't define e.g. _WIN32 etc), so set a reasonable default arch.
+    T.setArch(Triple::x86_64);
+    break;
+  }
+  T.setOS(Triple::Win32);
+  T.setVendor(Triple::PC);
+  T.setEnvironment(Triple::MSVC);
+  T.setObjectFormat(Triple::COFF);
   return T.str();
 }