Win64: Put a REX_W prefix on all TAILJMP* instructions
MSDN's x64 software conventions page says that this is one of the fixed
list of legal epilogues:
https://msdn.microsoft.com/en-us/library/tawsa7cb.aspx
Presumably this is how the unwinder distinguishes epilogue jumps from
in-function control flow.
Also normalize the way we place "## TAILCALL" comments on such jumps.
llvm-svn: 227611
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index f64e5d4..930163c 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -1123,10 +1123,12 @@
}
// Jump to label or value in register.
+ bool IsWin64 = STI.isTargetWin64();
if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) {
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNdi)
- ? X86::TAILJMPd : X86::TAILJMPd64));
+ unsigned Op = (RetOpcode == X86::TCRETURNdi)
+ ? X86::TAILJMPd
+ : (IsWin64 ? X86::TAILJMPd64_REX : X86::TAILJMPd64);
+ MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op));
if (JumpTarget.isGlobal())
MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
JumpTarget.getTargetFlags());
@@ -1136,14 +1138,16 @@
JumpTarget.getTargetFlags());
}
} else if (RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64) {
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNmi)
- ? X86::TAILJMPm : X86::TAILJMPm64));
+ unsigned Op = (RetOpcode == X86::TCRETURNmi)
+ ? X86::TAILJMPm
+ : (IsWin64 ? X86::TAILJMPm64_REX : X86::TAILJMPm64);
+ MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII.get(Op));
for (unsigned i = 0; i != 5; ++i)
MIB.addOperand(MBBI->getOperand(i));
} else if (RetOpcode == X86::TCRETURNri64) {
- BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr64)).
- addReg(JumpTarget.getReg(), RegState::Kill);
+ BuildMI(MBB, MBBI, DL,
+ TII.get(IsWin64 ? X86::TAILJMPr64_REX : X86::TAILJMPr64))
+ .addReg(JumpTarget.getReg(), RegState::Kill);
} else {
BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr)).
addReg(JumpTarget.getReg(), RegState::Kill);
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index f103288..cabeba6 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -21441,6 +21441,9 @@
case X86::TAILJMPd64:
case X86::TAILJMPr64:
case X86::TAILJMPm64:
+ case X86::TAILJMPd64_REX:
+ case X86::TAILJMPr64_REX:
+ case X86::TAILJMPm64_REX:
llvm_unreachable("TAILJMP64 would not be touched here.");
case X86::TCRETURNdi64:
case X86::TCRETURNri64:
diff --git a/llvm/lib/Target/X86/X86InstrControl.td b/llvm/lib/Target/X86/X86InstrControl.td
index e1c36a8..6ab961f 100644
--- a/llvm/lib/Target/X86/X86InstrControl.td
+++ b/llvm/lib/Target/X86/X86InstrControl.td
@@ -240,13 +240,13 @@
// mcinst.
def TAILJMPd : Ii32PCRel<0xE9, RawFrm, (outs),
(ins i32imm_pcrel:$dst),
- "jmp\t$dst # TAILCALL",
+ "jmp\t$dst",
[], IIC_JMP_REL>;
def TAILJMPr : I<0xFF, MRM4r, (outs), (ins ptr_rc_tailcall:$dst),
"", [], IIC_JMP_REG>; // FIXME: Remove encoding when JIT is dead.
let mayLoad = 1 in
def TAILJMPm : I<0xFF, MRM4m, (outs), (ins i32mem_TC:$dst),
- "jmp{l}\t{*}$dst # TAILCALL", [], IIC_JMP_MEM>;
+ "jmp{l}\t{*}$dst", [], IIC_JMP_MEM>;
}
@@ -290,13 +290,25 @@
def TCRETURNmi64 : PseudoI<(outs),
(ins i64mem_TC:$dst, i32imm:$offset), []>;
- def TAILJMPd64 : Ii32PCRel<0xE9, RawFrm, (outs),
- (ins i64i32imm_pcrel:$dst),
- "jmp\t$dst # TAILCALL", [], IIC_JMP_REL>;
+ def TAILJMPd64 : Ii32PCRel<0xE9, RawFrm, (outs), (ins i64i32imm_pcrel:$dst),
+ "jmp\t$dst", [], IIC_JMP_REL>;
def TAILJMPr64 : I<0xFF, MRM4r, (outs), (ins ptr_rc_tailcall:$dst),
- "jmp{q}\t{*}$dst # TAILCALL", [], IIC_JMP_MEM>;
+ "jmp{q}\t{*}$dst", [], IIC_JMP_MEM>;
let mayLoad = 1 in
def TAILJMPm64 : I<0xFF, MRM4m, (outs), (ins i64mem_TC:$dst),
- "jmp{q}\t{*}$dst # TAILCALL", [], IIC_JMP_MEM>;
+ "jmp{q}\t{*}$dst", [], IIC_JMP_MEM>;
+
+ // Win64 wants jumps leaving the function to have a REX_W prefix.
+ let hasREX_WPrefix = 1 in {
+ def TAILJMPd64_REX : Ii32PCRel<0xE9, RawFrm, (outs),
+ (ins i64i32imm_pcrel:$dst),
+ "rex64 jmp\t$dst", [], IIC_JMP_REL>;
+ def TAILJMPr64_REX : I<0xFF, MRM4r, (outs), (ins ptr_rc_tailcall:$dst),
+ "rex64 jmp{q}\t{*}$dst", [], IIC_JMP_MEM>;
+
+ let mayLoad = 1 in
+ def TAILJMPm64_REX : I<0xFF, MRM4m, (outs), (ins i64mem_TC:$dst),
+ "rex64 jmp{q}\t{*}$dst", [], IIC_JMP_MEM>;
+ }
}
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 60b0cb8..24a7588 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -353,6 +353,7 @@
{ X86::SETSr, X86::SETSm, TB_FOLDED_STORE },
{ X86::TAILJMPr, X86::TAILJMPm, TB_FOLDED_LOAD },
{ X86::TAILJMPr64, X86::TAILJMPm64, TB_FOLDED_LOAD },
+ { X86::TAILJMPr64_REX, X86::TAILJMPm64_REX, TB_FOLDED_LOAD },
{ X86::TEST16ri, X86::TEST16mi, TB_FOLDED_LOAD },
{ X86::TEST32ri, X86::TEST32mi, TB_FOLDED_LOAD },
{ X86::TEST64ri32, X86::TEST64mi32, TB_FOLDED_LOAD },
diff --git a/llvm/lib/Target/X86/X86InstrInfo.td b/llvm/lib/Target/X86/X86InstrInfo.td
index 327727a..e850ebd 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.td
+++ b/llvm/lib/Target/X86/X86InstrInfo.td
@@ -795,6 +795,7 @@
def In32BitMode : Predicate<"Subtarget->is32Bit()">,
AssemblerPredicate<"Mode32Bit", "32-bit mode">;
def IsWin64 : Predicate<"Subtarget->isTargetWin64()">;
+def NotWin64 : Predicate<"!Subtarget->isTargetWin64()">;
def IsPS4 : Predicate<"Subtarget->isTargetPS4()">;
def NotPS4 : Predicate<"!Subtarget->isTargetPS4()">;
def IsNaCl : Predicate<"Subtarget->isTargetNaCl()">;
diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index 5436fc2..99b1aa2 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -509,6 +509,7 @@
// inputs modeled as normal uses instead of implicit uses. As such, truncate
// off all but the first operand (the callee). FIXME: Change isel.
case X86::TAILJMPr64:
+ case X86::TAILJMPr64_REX:
case X86::CALL64r:
case X86::CALL64pcrel32: {
unsigned Opcode = OutMI.getOpcode();
@@ -1010,8 +1011,14 @@
break;
}
case X86::TAILJMPr:
+ case X86::TAILJMPm:
case X86::TAILJMPd:
+ case X86::TAILJMPr64:
+ case X86::TAILJMPm64:
case X86::TAILJMPd64:
+ case X86::TAILJMPr64_REX:
+ case X86::TAILJMPm64_REX:
+ case X86::TAILJMPd64_REX:
// Lower these as normal, but add some comments.
OutStreamer.AddComment("TAILCALL");
break;