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-rw-r--r--lib/Target/AArch64/AArch64InstrInfo.cpp122
-rw-r--r--test/CodeGen/AArch64/machine-outliner.mir16
2 files changed, 134 insertions, 4 deletions
diff --git a/lib/Target/AArch64/AArch64InstrInfo.cpp b/lib/Target/AArch64/AArch64InstrInfo.cpp
index 9e12b1a0e70..c4593731ccb 100644
--- a/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -26,6 +26,7 @@
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/StackMaps.h"
@@ -4747,6 +4748,20 @@ AArch64InstrInfo::getOutlininingCandidateInfo(
NumInstrsToCreateFrame = 1;
}
+ // Check if the range contains a call. These require a save + restore of the
+ // link register.
+ if (std::any_of(RepeatedSequenceLocs[0].first, RepeatedSequenceLocs[0].second,
+ [](const MachineInstr &MI) { return MI.isCall(); }))
+ NumInstrsToCreateFrame += 2; // Save + restore the link register.
+
+ // Handle the last instruction separately. If this is a tail call, then the
+ // last instruction is a call. We don't want to save + restore in this case.
+ // However, it could be possible that the last instruction is a call without
+ // it being valid to tail call this sequence. We should consider this as well.
+ else if (RepeatedSequenceLocs[0].second->isCall() &&
+ FrameID != MachineOutlinerTailCall)
+ NumInstrsToCreateFrame += 2;
+
return MachineOutlinerInfo(NumInstrsForCall, NumInstrsToCreateFrame, CallID,
FrameID);
}
@@ -4796,6 +4811,70 @@ AArch64InstrInfo::getOutliningType(MachineInstr &MI) const {
return MachineOutlinerInstrType::Illegal;
}
+ // Outline calls without stack parameters or aggregate parameters.
+ if (MI.isCall()) {
+ assert(MF->getFunction() && "MF doesn't have a function?");
+ const Module *M = MF->getFunction()->getParent();
+ assert(M && "No module?");
+
+ // Get the function associated with the call. Look at each operand and find
+ // the one that represents the callee and get its name.
+ Function *Callee = nullptr;
+ for (const MachineOperand &MOP : MI.operands()) {
+ if (MOP.isSymbol()) {
+ Callee = M->getFunction(MOP.getSymbolName());
+ break;
+ }
+
+ else if (MOP.isGlobal()) {
+ Callee = M->getFunction(MOP.getGlobal()->getGlobalIdentifier());
+ break;
+ }
+ }
+
+ // Only handle functions that we have information about.
+ if (!Callee)
+ return MachineOutlinerInstrType::Illegal;
+
+ // We have a function we have information about. Check it if it's something
+ // can safely outline.
+
+ // If the callee is vararg, it passes parameters on the stack. Don't touch
+ // it.
+ // FIXME: Functions like printf are very common and we should be able to
+ // outline them.
+ if (Callee->isVarArg())
+ return MachineOutlinerInstrType::Illegal;
+
+ // Check if any of the arguments are a pointer to a struct. We don't want
+ // to outline these since they might be loaded in two instructions.
+ for (Argument &Arg : Callee->args()) {
+ if (Arg.getType()->isPointerTy() &&
+ Arg.getType()->getPointerElementType()->isAggregateType())
+ return MachineOutlinerInstrType::Illegal;
+ }
+
+ // If the thing we're calling doesn't access memory at all, then we're good
+ // to go.
+ if (Callee->doesNotAccessMemory())
+ return MachineOutlinerInstrType::Legal;
+
+ // It accesses memory. Get the machine function for the callee to see if
+ // it's safe to outline.
+ MachineFunction *CalleeMF = MF->getMMI().getMachineFunction(*Callee);
+
+ // We don't know what's going on with the callee at all. Don't touch it.
+ if (!CalleeMF)
+ return MachineOutlinerInstrType::Illegal;
+
+ // Does it pass anything on the stack? If it does, don't outline it.
+ if (CalleeMF->getInfo<AArch64FunctionInfo>()->getBytesInStackArgArea() != 0)
+ return MachineOutlinerInstrType::Illegal;
+
+ // It doesn't, so it's safe to outline and we're done.
+ return MachineOutlinerInstrType::Legal;
+ }
+
// Don't outline positions.
if (MI.isPosition())
return MachineOutlinerInstrType::Illegal;
@@ -4820,7 +4899,6 @@ AArch64InstrInfo::getOutliningType(MachineInstr &MI) const {
if (MI.modifiesRegister(AArch64::SP, &RI) ||
MI.readsRegister(AArch64::SP, &RI)) {
- // Is it a memory operation?
if (MI.mayLoadOrStore()) {
unsigned Base; // Filled with the base regiser of MI.
int64_t Offset; // Filled with the offset of MI.
@@ -4841,12 +4919,11 @@ AArch64InstrInfo::getOutliningType(MachineInstr &MI) const {
// TODO: We should really test what happens if an instruction overflows.
// This is tricky to test with IR tests, but when the outliner is moved
// to a MIR test, it really ought to be checked.
-
Offset += 16; // Update the offset to what it would be if we outlined.
if (Offset < MinOffset * Scale || Offset > MaxOffset * Scale)
return MachineOutlinerInstrType::Illegal;
-
- // It's in range, so we can outline it.
+
+ // It's in range, so we can outline it.
return MachineOutlinerInstrType::Legal;
}
@@ -4889,6 +4966,43 @@ void AArch64InstrInfo::insertOutlinerEpilogue(
MachineBasicBlock &MBB, MachineFunction &MF,
const MachineOutlinerInfo &MInfo) const {
+ bool ContainsCalls = false;
+
+ for (MachineInstr &MI : MBB) {
+ if (MI.isCall()) {
+ ContainsCalls = true;
+ break;
+ }
+ }
+
+ if (ContainsCalls) {
+ // Fix up the instructions in the range, since we're going to modify the
+ // stack.
+ fixupPostOutline(MBB);
+
+ MachineBasicBlock::iterator It = MBB.begin();
+ MachineBasicBlock::iterator Et = MBB.end();
+
+ if (MInfo.FrameConstructionID == MachineOutlinerTailCall)
+ Et = std::prev(MBB.end());
+
+ // Insert a save before the outlined region
+ MachineInstr *STRXpre = BuildMI(MF, DebugLoc(), get(AArch64::STRXpre))
+ .addReg(AArch64::SP, RegState::Define)
+ .addReg(AArch64::LR)
+ .addReg(AArch64::SP)
+ .addImm(-16);
+ It = MBB.insert(It, STRXpre);
+
+ // Insert a restore before the terminator for the function.
+ MachineInstr *LDRXpost = BuildMI(MF, DebugLoc(), get(AArch64::LDRXpost))
+ .addReg(AArch64::SP, RegState::Define)
+ .addReg(AArch64::LR, RegState::Define)
+ .addReg(AArch64::SP)
+ .addImm(16);
+ Et = MBB.insert(Et, LDRXpost);
+ }
+
// If this is a tail call outlined function, then there's already a return.
if (MInfo.FrameConstructionID == MachineOutlinerTailCall)
return;
diff --git a/test/CodeGen/AArch64/machine-outliner.mir b/test/CodeGen/AArch64/machine-outliner.mir
index ee3daf11c9f..708e2e42880 100644
--- a/test/CodeGen/AArch64/machine-outliner.mir
+++ b/test/CodeGen/AArch64/machine-outliner.mir
@@ -1,6 +1,10 @@
# RUN: llc -mtriple=aarch64--- -run-pass=machine-outliner %s -o - | FileCheck %s
--- |
+ define void @baz() #0 {
+ ret void
+ }
+
define i32 @main() #0 {
ret i32 0
}
@@ -80,6 +84,7 @@ body: |
---
# This test ensures that we can avoid saving LR when it's available.
# CHECK-LABEL: bb.1:
+# CHECK-NOT: BL @baz, implicit-def dead %lr, implicit %sp
# CHECK: BL @OUTLINED_FUNCTION_[[F1:[0-9]+]], implicit-def %lr, implicit %sp
# CHECK-NEXT: %w17 = ORRWri %wzr, 2
# CHECK-NEXT: BL @OUTLINED_FUNCTION_[[F1]], implicit-def %lr, implicit %sp
@@ -93,15 +98,19 @@ body: |
%fp = frame-setup ADDXri %sp, 16, 0
bb.1:
+ BL @baz, implicit-def dead %lr, implicit %sp
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
+ BL @baz, implicit-def dead %lr, implicit %sp
%w17 = ORRWri %wzr, 2
+ BL @baz, implicit-def dead %lr, implicit %sp
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
%w17 = ORRWri %wzr, 1
+ BL @baz, implicit-def dead %lr, implicit %sp
%w8 = ORRWri %wzr, 0
bb.2:
@@ -110,6 +119,13 @@ body: |
RET undef %lr
...
+---
+name: baz
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: %w0, %lr, %w8
+ RET undef %lr
# CHECK-LABEL: name: OUTLINED_FUNCTION_{{[0-9]}}
# CHECK=LABEL: name: OUTLINED_FUNCTION_{{[1-9]}}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-22 08:55:21 +0000