Use -mno-implicit-float by default for kernel/kext code. <rdar://13177960>
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
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 @@
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())) {