r312275 - [clang-cl] Explicitly set object format to COFF in CL mode

Oleg Ranevskyy via cfe-commits cfe-commits at lists.llvm.org
Thu Aug 31 13:31:31 PDT 2017

Author: oleg
Date: Thu Aug 31 13:31:30 2017
New Revision: 312275

URL: http://llvm.org/viewvc/llvm-project?rev=312275&view=rev
[clang-cl] Explicitly set object format to COFF in CL mode

Currently object format is taken from the default target triple. For toolchains with a non-COFF default target this may result in an object format inappropriate for pc-windows and lead to compilation issues. 

For example, the default triple `aarch64-linux-elf` may produce something like `aarch64-pc-windows-msvc19.0.24215-elf` in CL mode. Clang creates `MicrosoftARM64TargetInfo` for such triple with data layout `e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128`. On the other hand, the AArch64 backend in `computeDataLayout` detects a non-COFF target and selects `e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128` as data layout for little endian. Different layouts used by clang and the backend cause an error:
error: backend data layout 'e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128'
 does not match expected target description 'e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128'
This can be observed on the clang's Driver/cl-pch.c test with AArch64 as a default target.

This patch enforces COFF in CL mode.

Reviewers: hans

Reviewed By: hans

Subscribers: cfe-commits, aemerson, asl, kristof.beyls

Differential Revision: https://reviews.llvm.org/D37336


Modified: cfe/trunk/lib/Driver/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Driver.cpp?rev=312275&r1=312274&r2=312275&view=diff
--- cfe/trunk/lib/Driver/Driver.cpp (original)
+++ cfe/trunk/lib/Driver/Driver.cpp Thu Aug 31 13:31:30 2017
@@ -663,6 +663,7 @@ Compilation *Driver::BuildCompilation(Ar
+    T.setObjectFormat(llvm::Triple::COFF);
     DefaultTargetTriple = T.str();
   if (const Arg *A = Args.getLastArg(options::OPT_target))

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