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| author | Amjad Aboud <amjad.aboud@intel.com> | 2016-05-13 12:46:57 +0000 |
|---|---|---|
| committer | Amjad Aboud <amjad.aboud@intel.com> | 2016-05-13 12:46:57 +0000 |
| commit | 78b1fb01466818fd1296cd32805d4ecf1655fef8 (patch) | |
| tree | faa8fa17c68e1e3a7e64ad3eb4ec897753386497 /llvm/lib/Target/X86/X86FrameLowering.cpp | |
| parent | fc1186510b79c0dbc4ff521fcb37f6c83e564c71 (diff) | |
| download | bcm5719-llvm-78b1fb01466818fd1296cd32805d4ecf1655fef8.tar.gz bcm5719-llvm-78b1fb01466818fd1296cd32805d4ecf1655fef8.zip | |
Assure calling "cld" instruction in prologue of X86 interrupt handler function.
Differential Revision: http://reviews.llvm.org/D18725
llvm-svn: 269413
Diffstat (limited to 'llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86FrameLowering.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index 8a283775138..700ebf9e91c 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -1381,6 +1381,18 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF, if (PushedRegs) emitCalleeSavedFrameMoves(MBB, MBBI, DL); } + + // X86 Interrupt handling function cannot assume anything about the direction + // flag (DF in EFLAGS register). Clear this flag by creating "cld" instruction + // in each prologue of interrupt handler function. + // + // FIXME: Create "cld" instruction only in these cases: + // 1. The interrupt handling function uses any of the "rep" instructions. + // 2. Interrupt handling function calls another function. + // + if (Fn->getCallingConv() == CallingConv::X86_INTR) + BuildMI(MBB, MBBI, DL, TII.get(X86::CLD)) + .setMIFlag(MachineInstr::FrameSetup); } bool X86FrameLowering::canUseLEAForSPInEpilogue( |
