diff mbox

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

Message ID 20170427080932.11703-5-daniel.santos@pobox.com
State New
Headers show

Commit Message

Daniel Santos April 27, 2017, 8:09 a.m. UTC
Adds the options -mcall-ms2sysv-xlogues to i386.opt and i386.c and
documentation to invoke.texi.  Using -mcall-ms2sysv-xlogues on SEH
targets is currently unsupported and will result in a sorry ().  SEH
targets can be supported, but it would require adding support for
CFA_REG_EXPRESSION to the SEH unwind emit code in
gcc/config/i386/winnt.c -- this is the same for use of aligned SSE MOVs
after a realigned stack pointer.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
---
 gcc/config/i386/i386.c   |  6 +++++-
 gcc/config/i386/i386.opt |  4 ++++
 gcc/doc/invoke.texi      | 13 ++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

Comments

Sandra Loosemore April 27, 2017, 10:54 p.m. UTC | #1
On 04/27/2017 02:09 AM, Daniel Santos wrote:

> @@ -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 & restores,

s/&/and/

The documentation part is OK with that change.

-Sandra
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..c9e565a9216 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 & 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