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author | Reid Kleckner <reid@kleckner.net> | 2014-01-31 17:41:22 +0000 |
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committer | Reid Kleckner <reid@kleckner.net> | 2014-01-31 17:41:22 +0000 |
commit | 65c98b9da474d0562f883d6001f31ba5b2b95183 (patch) | |
tree | 18a2b8a062180aa9b4f289b5caa8db5e1d7aa061 /lib/Target/X86 | |
parent | 0cb94d9adc631eafa88218a5e972d45e0cf35f61 (diff) | |
download | llvm-65c98b9da474d0562f883d6001f31ba5b2b95183.tar.gz llvm-65c98b9da474d0562f883d6001f31ba5b2b95183.tar.bz2 llvm-65c98b9da474d0562f883d6001f31ba5b2b95183.tar.xz |
[ms-cxxabi] Add a new calling convention that swaps 'this' and 'sret'
MSVC always places the 'this' parameter for a method first. The
implicit 'sret' pointer for methods always comes second. We already
implement this for __thiscall by putting sret parameters on the stack,
but __cdecl methods require putting both parameters on the stack in
opposite order.
Using a special calling convention allows frontends to keep the sret
parameter first, which avoids breaking lots of assumptions in LLVM and
Clang.
Fixes PR15768 with the corresponding change in Clang.
Reviewers: ributzka, majnemer
Differential Revision: http://llvm-reviews.chandlerc.com/D2663
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200561 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86')
-rw-r--r-- | lib/Target/X86/X86CallingConv.h | 27 | ||||
-rw-r--r-- | lib/Target/X86/X86CallingConv.td | 10 |
2 files changed, 37 insertions, 0 deletions
diff --git a/lib/Target/X86/X86CallingConv.h b/lib/Target/X86/X86CallingConv.h index e76f9fda2d..040da3535e 100644 --- a/lib/Target/X86/X86CallingConv.h +++ b/lib/Target/X86/X86CallingConv.h @@ -29,6 +29,33 @@ inline bool CC_X86_AnyReg_Error(unsigned &, MVT &, MVT &, return false; } +inline bool CC_X86_CDeclMethod_SRet(unsigned &ValNo, MVT &ValVT, MVT &LocVT, + CCValAssign::LocInfo &LocInfo, + ISD::ArgFlagsTy &ArgFlags, CCState &State) { + // Swap the order of the first two parameters if the first parameter is sret. + if (ArgFlags.isSRet()) { + assert(ValNo == 0); + assert(ValVT == MVT::i32); + State.AllocateStack(8, 4); + State.addLoc(CCValAssign::getCustomMem(ValNo, ValVT, 4, LocVT, LocInfo)); + + // Indicate that we need to swap the order of the first and second + // parameters by "allocating" register zero. There are no register + // parameters with cdecl methods, so we can use this to communicate to the + // next call. + State.AllocateReg(1); + return true; + } else if (ValNo == 1 && State.isAllocated(1)) { + assert(ValVT == MVT::i32 && "non-i32-sized this param unsupported"); + // Stack was already allocated while processing sret. + State.addLoc(CCValAssign::getCustomMem(ValNo, ValVT, 0, LocVT, LocInfo)); + return true; + } + + // All other args use the C calling convention. + return false; +} + } // End llvm namespace #endif diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td index 5b51a1e8e0..f40a42ee9b 100644 --- a/lib/Target/X86/X86CallingConv.td +++ b/lib/Target/X86/X86CallingConv.td @@ -485,6 +485,15 @@ def CC_X86_32_ThisCall_Win : CallingConv<[ CCDelegateTo<CC_X86_32_ThisCall_Common> ]>; +def CC_X86_CDeclMethod : CallingConv<[ + // Promote i8/i16 arguments to i32. + CCIfType<[i8, i16], CCPromoteToType<i32>>, + + CCCustom<"CC_X86_CDeclMethod_SRet">, + + CCDelegateTo<CC_X86_32_Common> +]>; + def CC_X86_32_ThisCall : CallingConv<[ CCIfSubtarget<"isTargetCygMing()", CCDelegateTo<CC_X86_32_ThisCall_Mingw>>, CCDelegateTo<CC_X86_32_ThisCall_Win> @@ -574,6 +583,7 @@ def CC_Intel_OCL_BI : CallingConv<[ def CC_X86_32 : CallingConv<[ CCIfCC<"CallingConv::X86_FastCall", CCDelegateTo<CC_X86_32_FastCall>>, CCIfCC<"CallingConv::X86_ThisCall", CCDelegateTo<CC_X86_32_ThisCall>>, + CCIfCC<"CallingConv::X86_CDeclMethod", CCDelegateTo<CC_X86_CDeclMethod>>, CCIfCC<"CallingConv::Fast", CCDelegateTo<CC_X86_32_FastCC>>, CCIfCC<"CallingConv::GHC", CCDelegateTo<CC_X86_32_GHC>>, CCIfCC<"CallingConv::HiPE", CCDelegateTo<CC_X86_32_HiPE>>, |