> Date: Fri, 20 Jan 2017 21:41:37 +1000
> From: Patrick Wildt <[email protected]>
>
> Hi,
>
> currently our clang for ARM64 creates code thinking it can do unaligned
> access. Which is kinda true, since our kernel does not enforce strict
> alignment yet. The Pine64 on the other hand enforces strict alignment
> at least as long as EFI is running. This means efiboot needs to be
> compiled with strict alignment, while it wouldn't yet matter on kernel
> or userland.
>
> Still, we probably want to make strict alignment the default and then
> enforce it. This diff makes clang use strict alignment on OpenBSD if
> it wasn't overridden by any flags.
>
> ok?
ok kettenis@
Perhaps we should wait upstreaming this for a bit until we're sure it
is viable to enforce strict-alignment though.
> diff --git a/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
> b/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
> index bc7b9a98bb6..2e88668e866 100644
> --- a/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
> +++ b/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
> @@ -2470,7 +2470,9 @@ getAArch64MicroArchFeaturesFromMcpu(const Driver &D,
> StringRef Mcpu,
> return getAArch64MicroArchFeaturesFromMtune(D, CPU, Args, Features);
> }
>
> -static void getAArch64TargetFeatures(const Driver &D, const ArgList &Args,
> +static void getAArch64TargetFeatures(const Driver &D,
> + const llvm::Triple &Triple,
> + const ArgList &Args,
> std::vector<const char *> &Features) {
> Arg *A;
> bool success = true;
> @@ -2512,9 +2514,11 @@ static void getAArch64TargetFeatures(const Driver &D,
> const ArgList &Args,
> }
>
> if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
> - options::OPT_munaligned_access))
> + options::OPT_munaligned_access)) {
> if (A->getOption().matches(options::OPT_mno_unaligned_access))
> Features.push_back("+strict-align");
> + } else if (Triple.isOSOpenBSD())
> + Features.push_back("+strict-align");
>
> if (Args.hasArg(options::OPT_ffixed_x18))
> Features.push_back("+reserve-x18");
> @@ -2600,7 +2604,7 @@ static void getTargetFeatures(const ToolChain &TC,
> const llvm::Triple &Triple,
> break;
> case llvm::Triple::aarch64:
> case llvm::Triple::aarch64_be:
> - getAArch64TargetFeatures(D, Args, Features);
> + getAArch64TargetFeatures(D, Triple, Args, Features);
> break;
> case llvm::Triple::x86:
> case llvm::Triple::x86_64:
>
>
