From 2616e2ec85934f2a45add8fd0df30defe3b3a7ad Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Sun, 10 Feb 2013 16:01:41 +0000 Subject: [PATCH] Use -mno-implicit-float by default for kernel/kext code. Apple's kernel engineers have been expecting this behavior even though we've never implemented it before, as far as I can tell. In recent months, clang has gotten better at using vector instructions to optimize memcpy-like operations, and that has exposed problems when vector/floating-point instructions are used in kexts that don't support that. This behavior also matches what Apple's GCC did for PowerPC targets. llvm-svn: 174838 --- clang/lib/Driver/Tools.cpp | 16 ++++++++++++---- clang/test/Driver/flags.c | 6 ++++++ 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp index c5499de..0ed010e 100644 --- a/clang/lib/Driver/Tools.cpp +++ b/clang/lib/Driver/Tools.cpp @@ -1200,10 +1200,18 @@ void Clang::AddX86TargetArgs(const ArgList &Args, Args.hasArg(options::OPT_fapple_kext)) CmdArgs.push_back("-disable-red-zone"); - if (Args.hasFlag(options::OPT_msoft_float, - options::OPT_mno_soft_float, - false) || - Args.hasArg(options::OPT_mno_implicit_float)) + // Default to avoid implicit floating-point for kernel/kext code, but allow + // that to be overridden with -mno-soft-float. + bool NoImplicitFloat = (Args.hasArg(options::OPT_mkernel) || + Args.hasArg(options::OPT_fapple_kext)); + if (Arg *A = Args.getLastArg(options::OPT_msoft_float, + options::OPT_mno_soft_float, + options::OPT_mno_implicit_float)) { + const Option &O = A->getOption(); + NoImplicitFloat = (O.matches(options::OPT_mno_implicit_float) || + O.matches(options::OPT_msoft_float)); + } + if (NoImplicitFloat) CmdArgs.push_back("-no-implicit-float"); if (const char *CPUName = getX86TargetCPU(Args, getToolChain().getTriple())) { diff --git a/clang/test/Driver/flags.c b/clang/test/Driver/flags.c index d328b82..2786231 100644 --- a/clang/test/Driver/flags.c +++ b/clang/test/Driver/flags.c @@ -10,5 +10,11 @@ // RUN: %clang -target i386-apple-darwin9 -### -S -mno-implicit-float %s 2> %t.log // RUN: grep '"-no-implicit-float"' %t.log +// RUN: %clang -target i386-apple-darwin9 -### -S -mkernel %s 2> %t.log +// RUN: grep '"-no-implicit-float"' %t.log + +// RUN: %clang -target i386-apple-darwin9 -### -S -mkernel -mno-soft-float %s 2> %t.log +// RUN: grep '"-no-implicit-float"' %t.log | count 0 + // RUN: %clang -target armv7-apple-darwin10 -### -S -mno-implicit-float %s 2> %t.log // RUN: grep '"-no-implicit-float"' %t.log -- 2.7.4