diff mbox

[05/12,rev,1,i386] Add option -mcall-ms2sysv-xlogues

Message ID 20170428061216.17586-1-daniel.santos@pobox.com
State New
Headers show

Commit Message

Daniel Santos April 28, 2017, 6:12 a.m. UTC 
Oops.  I blame my fingers.  :)

Daniel
---
 gcc/config/i386/i386.c   |  6 +++++-
 gcc/config/i386/i386.opt |  4 ++++
 gcc/doc/invoke.texi      | 13 ++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 113f83742c2..521116195cb 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4508,7 +4508,8 @@  ix86_target_string (HOST_WIDE_INT isa, HOST_WIDE_INT isa2,
     { "-mstv",				MASK_STV },
     { "-mavx256-split-unaligned-load",	MASK_AVX256_SPLIT_UNALIGNED_LOAD },
     { "-mavx256-split-unaligned-store",	MASK_AVX256_SPLIT_UNALIGNED_STORE },
-    { "-mprefer-avx128",		MASK_PREFER_AVX128 }
+    { "-mprefer-avx128",		MASK_PREFER_AVX128 },
+    { "-mcall-ms2sysv-xlogues",		MASK_CALL_MS2SYSV_XLOGUES }
   };
 
   /* Additional flag options.  */
@@ -6319,6 +6320,9 @@  ix86_option_override_internal (bool main_args_p,
 #endif
    }
 
+  if (TARGET_SEH && TARGET_CALL_MS2SYSV_XLOGUES)
+    sorry ("-mcall-ms2sysv-xlogues isn%'t currently supported with SEH");
+
   if (!(opts_set->x_target_flags & MASK_VZEROUPPER))
     opts->x_target_flags |= MASK_VZEROUPPER;
   if (!(opts_set->x_target_flags & MASK_STV))
diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
index 9384e29b1de..65b228544a5 100644
--- a/gcc/config/i386/i386.opt
+++ b/gcc/config/i386/i386.opt
@@ -538,6 +538,10 @@  Enum(calling_abi) String(sysv) Value(SYSV_ABI)
 EnumValue
 Enum(calling_abi) String(ms) Value(MS_ABI)
 
+mcall-ms2sysv-xlogues
+Target Report Mask(CALL_MS2SYSV_XLOGUES) Save
+Use libgcc stubs to save and restore registers clobbered by 64-bit Microsoft to System V ABI calls.
+
 mveclibabi=
 Target RejectNegative Joined Var(ix86_veclibabi_type) Enum(ix86_veclibabi) Init(ix86_veclibabi_type_none)
 Vector library ABI to use.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 0eeea7b3b87..d9894f37ee5 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1209,7 +1209,7 @@  See RS/6000 and PowerPC Options.
 -msse2avx  -mfentry  -mrecord-mcount  -mnop-mcount  -m8bit-idiv @gol
 -mavx256-split-unaligned-load  -mavx256-split-unaligned-store @gol
 -malign-data=@var{type}  -mstack-protector-guard=@var{guard} @gol
--mmitigate-rop  -mgeneral-regs-only}
+-mmitigate-rop  -mgeneral-regs-only  -mcall-ms2sysv-xlogues}
 
 @emph{x86 Windows Options}
 @gccoptlist{-mconsole  -mcygwin  -mno-cygwin  -mdll @gol
@@ -25308,6 +25308,17 @@  You can control this behavior for specific functions by
 using the function attributes @code{ms_abi} and @code{sysv_abi}.
 @xref{Function Attributes}.
 
+@item -mcall-ms2sysv-xlogues
+@opindex mcall-ms2sysv-xlogues
+@opindex mno-call-ms2sysv-xlogues
+Due to differences in 64-bit ABIs, any Microsoft ABI function that calls a
+System V ABI function must consider RSI, RDI and XMM6-15 as clobbered.  By
+default, the code for saving and restoring these registers is emitted inline,
+resulting in fairly lengthy prologues and epilogues.  Using
+@option{-mcall-ms2sysv-xlogues} emits prologues and epilogues that
+use stubs in the static portion of libgcc to perform these saves and restores,
+thus reducing function size at the cost of a few extra instructions.
+
 @item -mtls-dialect=@var{type}
 @opindex mtls-dialect
 Generate code to access thread-local storage using the @samp{gnu} or