From f0c5456d7d6a9f74281011297d86cb3b1fa53cc1 Mon Sep 17 00:00:00 2001
From: Bob Wilson <bob.wilson@apple.com>
Date: Sun, 10 Feb 2013 16:01:41 +0000
Subject: [PATCH] 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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174838 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Driver/Tools.cpp | 16 ++++++++++++----
test/Driver/flags.c | 6 ++++++
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index c5499dea769..0ed010e4ea3 100644
--- a/lib/Driver/Tools.cpp
+++ b/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/test/Driver/flags.c b/test/Driver/flags.c
index d328b827bb6..27862316f88 100644
--- a/test/Driver/flags.c
+++ b/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
--
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