[AArch64] Support stackmap/patchpoint in getInstSizeInBytes
We currently return 4 for stackmaps and patchpoints, which is very optimistic
and can in rare cases cause the branch relaxation pass to fail to relax certain
branches.
This patch causes getInstSizeInBytes to return a pessimistic estimate of the
size as the number of bytes requested in the stackmap/patchpoint. In the future,
we could provide a more accurate estimate by sharing some of the logic in
AArch64::LowerSTACKMAP/PATCHPOINT.
Fixes part of https://llvm.org/bugs/show_bug.cgi?id=28750
Differential Revision: https://reviews.llvm.org/D24073
llvm-svn: 281301
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 6e77743..39ac480 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -19,6 +19,7 @@
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
+#include "llvm/CodeGen/StackMaps.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
@@ -58,22 +59,38 @@
if (MI.getOpcode() == AArch64::INLINEASM)
return getInlineAsmLength(MI.getOperand(0).getSymbolName(), *MAI);
+ // FIXME: We currently only handle pseudoinstructions that don't get expanded
+ // before the assembly printer.
+ unsigned NumBytes = 0;
const MCInstrDesc &Desc = MI.getDesc();
switch (Desc.getOpcode()) {
default:
// Anything not explicitly designated otherwise is a normal 4-byte insn.
- return 4;
+ NumBytes = 4;
+ break;
case TargetOpcode::DBG_VALUE:
case TargetOpcode::EH_LABEL:
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
- return 0;
+ NumBytes = 0;
+ break;
+ case TargetOpcode::STACKMAP:
+ // The upper bound for a stackmap intrinsic is the full length of its shadow
+ NumBytes = StackMapOpers(&MI).getNumPatchBytes();
+ assert(NumBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
+ break;
+ case TargetOpcode::PATCHPOINT:
+ // The size of the patchpoint intrinsic is the number of bytes requested
+ NumBytes = PatchPointOpers(&MI).getNumPatchBytes();
+ assert(NumBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
+ break;
case AArch64::TLSDESC_CALLSEQ:
// This gets lowered to an instruction sequence which takes 16 bytes
- return 16;
+ NumBytes = 16;
+ break;
}
- llvm_unreachable("getInstSizeInBytes()- Unable to determine insn size");
+ return NumBytes;
}
static void parseCondBranch(MachineInstr *LastInst, MachineBasicBlock *&Target,