llvm16 targets

1 files changed, 388 insertions, 0 deletions

diff --git a/contrib/libs/llvm16/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp b/contrib/libs/llvm16/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
new file mode 100644
index 00000000000..e60f1397b99
--- /dev/null
+++ b/contrib/libs/llvm16/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
@@ -0,0 +1,388 @@
+//===-- WebAssemblyFrameLowering.cpp - WebAssembly Frame Lowering ----------==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the WebAssembly implementation of
+/// TargetFrameLowering class.
+///
+/// On WebAssembly, there aren't a lot of things to do here. There are no
+/// callee-saved registers to save, and no spill slots.
+///
+/// The stack grows downward.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssemblyFrameLowering.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "Utils/WebAssemblyTypeUtilities.h"
+#include "WebAssembly.h"
+#include "WebAssemblyInstrInfo.h"
+#include "WebAssemblyMachineFunctionInfo.h"
+#include "WebAssemblySubtarget.h"
+#include "WebAssemblyTargetMachine.h"
+#include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfoImpls.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "wasm-frame-info"
+
+// TODO: wasm64
+// TODO: Emit TargetOpcode::CFI_INSTRUCTION instructions
+
+// In an ideal world, when objects are added to the MachineFrameInfo by
+// FunctionLoweringInfo::set, we could somehow hook into target-specific code to
+// ensure they are assigned the right stack ID.  However there isn't a hook that
+// runs between then and DAG building time, though, so instead we hoist stack
+// objects lazily when they are first used, and comprehensively after the DAG is
+// built via the PreprocessISelDAG hook, called by the
+// SelectionDAGISel::runOnMachineFunction.  We have to do it in two places
+// because we want to do it while building the selection DAG for uses of alloca,
+// but not all alloca instructions are used so we have to follow up afterwards.
+std::optional<unsigned>
+WebAssemblyFrameLowering::getLocalForStackObject(MachineFunction &MF,
+                                                 int FrameIndex) {
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+
+  // If already hoisted to a local, done.
+  if (MFI.getStackID(FrameIndex) == TargetStackID::WasmLocal)
+    return static_cast<unsigned>(MFI.getObjectOffset(FrameIndex));
+
+  // If not allocated in the object address space, this object will be in
+  // linear memory.
+  const AllocaInst *AI = MFI.getObjectAllocation(FrameIndex);
+  if (!AI || !WebAssembly::isWasmVarAddressSpace(AI->getAddressSpace()))
+    return std::nullopt;
+
+  // Otherwise, allocate this object in the named value stack, outside of linear
+  // memory.
+  SmallVector<EVT, 4> ValueVTs;
+  const WebAssemblyTargetLowering &TLI =
+      *MF.getSubtarget<WebAssemblySubtarget>().getTargetLowering();
+  WebAssemblyFunctionInfo *FuncInfo = MF.getInfo<WebAssemblyFunctionInfo>();
+  ComputeValueVTs(TLI, MF.getDataLayout(), AI->getAllocatedType(), ValueVTs);
+  MFI.setStackID(FrameIndex, TargetStackID::WasmLocal);
+  // Abuse SP offset to record the index of the first local in the object.
+  unsigned Local = FuncInfo->getParams().size() + FuncInfo->getLocals().size();
+  MFI.setObjectOffset(FrameIndex, Local);
+  // Allocate WebAssembly locals for each non-aggregate component of the
+  // allocation.
+  for (EVT ValueVT : ValueVTs)
+    FuncInfo->addLocal(ValueVT.getSimpleVT());
+  // Abuse object size to record number of WebAssembly locals allocated to
+  // this object.
+  MFI.setObjectSize(FrameIndex, ValueVTs.size());
+  return static_cast<unsigned>(Local);
+}
+
+/// We need a base pointer in the case of having items on the stack that
+/// require stricter alignment than the stack pointer itself.  Because we need
+/// to shift the stack pointer by some unknown amount to force the alignment,
+/// we need to record the value of the stack pointer on entry to the function.
+bool WebAssemblyFrameLowering::hasBP(const MachineFunction &MF) const {
+  const auto *RegInfo =
+      MF.getSubtarget<WebAssemblySubtarget>().getRegisterInfo();
+  return RegInfo->hasStackRealignment(MF);
+}
+
+/// Return true if the specified function should have a dedicated frame pointer
+/// register.
+bool WebAssemblyFrameLowering::hasFP(const MachineFunction &MF) const {
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+
+  // When we have var-sized objects, we move the stack pointer by an unknown
+  // amount, and need to emit a frame pointer to restore the stack to where we
+  // were on function entry.
+  // If we already need a base pointer, we use that to fix up the stack pointer.
+  // If there are no fixed-size objects, we would have no use of a frame
+  // pointer, and thus should not emit one.
+  bool HasFixedSizedObjects = MFI.getStackSize() > 0;
+  bool NeedsFixedReference = !hasBP(MF) || HasFixedSizedObjects;
+
+  return MFI.isFrameAddressTaken() ||
+         (MFI.hasVarSizedObjects() && NeedsFixedReference) ||
+         MFI.hasStackMap() || MFI.hasPatchPoint();
+}
+
+/// Under normal circumstances, when a frame pointer is not required, we reserve
+/// argument space for call sites in the function immediately on entry to the
+/// current function. This eliminates the need for add/sub sp brackets around
+/// call sites. Returns true if the call frame is included as part of the stack
+/// frame.
+bool WebAssemblyFrameLowering::hasReservedCallFrame(
+    const MachineFunction &MF) const {
+  return !MF.getFrameInfo().hasVarSizedObjects();
+}
+
+// Returns true if this function needs a local user-space stack pointer for its
+// local frame (not for exception handling).
+bool WebAssemblyFrameLowering::needsSPForLocalFrame(
+    const MachineFunction &MF) const {
+  auto &MFI = MF.getFrameInfo();
+  return MFI.getStackSize() || MFI.adjustsStack() || hasFP(MF);
+}
+
+// In function with EH pads, we need to make a copy of the value of
+// __stack_pointer global in SP32/64 register, in order to use it when
+// restoring __stack_pointer after an exception is caught.
+bool WebAssemblyFrameLowering::needsPrologForEH(
+    const MachineFunction &MF) const {
+  auto EHType = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType();
+  return EHType == ExceptionHandling::Wasm &&
+         MF.getFunction().hasPersonalityFn() && MF.getFrameInfo().hasCalls();
+}
+
+/// Returns true if this function needs a local user-space stack pointer.
+/// Unlike a machine stack pointer, the wasm user stack pointer is a global
+/// variable, so it is loaded into a register in the prolog.
+bool WebAssemblyFrameLowering::needsSP(const MachineFunction &MF) const {
+  return needsSPForLocalFrame(MF) || needsPrologForEH(MF);
+}
+
+/// Returns true if the local user-space stack pointer needs to be written back
+/// to __stack_pointer global by this function (this is not meaningful if
+/// needsSP is false). If false, the stack red zone can be used and only a local
+/// SP is needed.
+bool WebAssemblyFrameLowering::needsSPWriteback(
+    const MachineFunction &MF) const {
+  auto &MFI = MF.getFrameInfo();
+  assert(needsSP(MF));
+  // When we don't need a local stack pointer for its local frame but only to
+  // support EH, we don't need to write SP back in the epilog, because we don't
+  // bump down the stack pointer in the prolog. We need to write SP back in the
+  // epilog only if
+  // 1. We need SP not only for EH support but also because we actually use
+  // stack or we have a frame address taken.
+  // 2. We cannot use the red zone.
+  bool CanUseRedZone = MFI.getStackSize() <= RedZoneSize && !MFI.hasCalls() &&
+                       !MF.getFunction().hasFnAttribute(Attribute::NoRedZone);
+  return needsSPForLocalFrame(MF) && !CanUseRedZone;
+}
+
+unsigned WebAssemblyFrameLowering::getSPReg(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::SP64
+             : WebAssembly::SP32;
+}
+
+unsigned WebAssemblyFrameLowering::getFPReg(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::FP64
+             : WebAssembly::FP32;
+}
+
+unsigned
+WebAssemblyFrameLowering::getOpcConst(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::CONST_I64
+             : WebAssembly::CONST_I32;
+}
+
+unsigned WebAssemblyFrameLowering::getOpcAdd(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::ADD_I64
+             : WebAssembly::ADD_I32;
+}
+
+unsigned WebAssemblyFrameLowering::getOpcSub(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::SUB_I64
+             : WebAssembly::SUB_I32;
+}
+
+unsigned WebAssemblyFrameLowering::getOpcAnd(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::AND_I64
+             : WebAssembly::AND_I32;
+}
+
+unsigned
+WebAssemblyFrameLowering::getOpcGlobGet(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::GLOBAL_GET_I64
+             : WebAssembly::GLOBAL_GET_I32;
+}
+
+unsigned
+WebAssemblyFrameLowering::getOpcGlobSet(const MachineFunction &MF) {
+  return MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()
+             ? WebAssembly::GLOBAL_SET_I64
+             : WebAssembly::GLOBAL_SET_I32;
+}
+
+void WebAssemblyFrameLowering::writeSPToGlobal(
+    unsigned SrcReg, MachineFunction &MF, MachineBasicBlock &MBB,
+    MachineBasicBlock::iterator &InsertStore, const DebugLoc &DL) const {
+  const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
+
+  const char *ES = "__stack_pointer";
+  auto *SPSymbol = MF.createExternalSymbolName(ES);
+
+  BuildMI(MBB, InsertStore, DL, TII->get(getOpcGlobSet(MF)))
+      .addExternalSymbol(SPSymbol)
+      .addReg(SrcReg);
+}
+
+MachineBasicBlock::iterator
+WebAssemblyFrameLowering::eliminateCallFramePseudoInstr(
+    MachineFunction &MF, MachineBasicBlock &MBB,
+    MachineBasicBlock::iterator I) const {
+  assert(!I->getOperand(0).getImm() && (hasFP(MF) || hasBP(MF)) &&
+         "Call frame pseudos should only be used for dynamic stack adjustment");
+  auto &ST = MF.getSubtarget<WebAssemblySubtarget>();
+  const auto *TII = ST.getInstrInfo();
+  if (I->getOpcode() == TII->getCallFrameDestroyOpcode() &&
+      needsSPWriteback(MF)) {
+    DebugLoc DL = I->getDebugLoc();
+    writeSPToGlobal(getSPReg(MF), MF, MBB, I, DL);
+  }
+  return MBB.erase(I);
+}
+
+void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
+                                            MachineBasicBlock &MBB) const {
+  // TODO: Do ".setMIFlag(MachineInstr::FrameSetup)" on emitted instructions
+  auto &MFI = MF.getFrameInfo();
+  assert(MFI.getCalleeSavedInfo().empty() &&
+         "WebAssembly should not have callee-saved registers");
+
+  if (!needsSP(MF))
+    return;
+  uint64_t StackSize = MFI.getStackSize();
+
+  auto &ST = MF.getSubtarget<WebAssemblySubtarget>();
+  const auto *TII = ST.getInstrInfo();
+  auto &MRI = MF.getRegInfo();
+
+  auto InsertPt = MBB.begin();
+  while (InsertPt != MBB.end() &&
+         WebAssembly::isArgument(InsertPt->getOpcode()))
+    ++InsertPt;
+  DebugLoc DL;
+
+  const TargetRegisterClass *PtrRC =
+      MRI.getTargetRegisterInfo()->getPointerRegClass(MF);
+  unsigned SPReg = getSPReg(MF);
+  if (StackSize)
+    SPReg = MRI.createVirtualRegister(PtrRC);
+
+  const char *ES = "__stack_pointer";
+  auto *SPSymbol = MF.createExternalSymbolName(ES);
+  BuildMI(MBB, InsertPt, DL, TII->get(getOpcGlobGet(MF)), SPReg)
+      .addExternalSymbol(SPSymbol);
+
+  bool HasBP = hasBP(MF);
+  if (HasBP) {
+    auto FI = MF.getInfo<WebAssemblyFunctionInfo>();
+    Register BasePtr = MRI.createVirtualRegister(PtrRC);
+    FI->setBasePointerVreg(BasePtr);
+    BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::COPY), BasePtr)
+        .addReg(SPReg);
+  }
+  if (StackSize) {
+    // Subtract the frame size
+    Register OffsetReg = MRI.createVirtualRegister(PtrRC);
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcConst(MF)), OffsetReg)
+        .addImm(StackSize);
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcSub(MF)), getSPReg(MF))
+        .addReg(SPReg)
+        .addReg(OffsetReg);
+  }
+  if (HasBP) {
+    Register BitmaskReg = MRI.createVirtualRegister(PtrRC);
+    Align Alignment = MFI.getMaxAlign();
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcConst(MF)), BitmaskReg)
+        .addImm((int64_t) ~(Alignment.value() - 1));
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcAnd(MF)), getSPReg(MF))
+        .addReg(getSPReg(MF))
+        .addReg(BitmaskReg);
+  }
+  if (hasFP(MF)) {
+    // Unlike most conventional targets (where FP points to the saved FP),
+    // FP points to the bottom of the fixed-size locals, so we can use positive
+    // offsets in load/store instructions.
+    BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::COPY), getFPReg(MF))
+        .addReg(getSPReg(MF));
+  }
+  if (StackSize && needsSPWriteback(MF)) {
+    writeSPToGlobal(getSPReg(MF), MF, MBB, InsertPt, DL);
+  }
+}
+
+void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
+                                            MachineBasicBlock &MBB) const {
+  uint64_t StackSize = MF.getFrameInfo().getStackSize();
+  if (!needsSP(MF) || !needsSPWriteback(MF))
+    return;
+  auto &ST = MF.getSubtarget<WebAssemblySubtarget>();
+  const auto *TII = ST.getInstrInfo();
+  auto &MRI = MF.getRegInfo();
+  auto InsertPt = MBB.getFirstTerminator();
+  DebugLoc DL;
+
+  if (InsertPt != MBB.end())
+    DL = InsertPt->getDebugLoc();
+
+  // Restore the stack pointer. If we had fixed-size locals, add the offset
+  // subtracted in the prolog.
+  unsigned SPReg = 0;
+  unsigned SPFPReg = hasFP(MF) ? getFPReg(MF) : getSPReg(MF);
+  if (hasBP(MF)) {
+    auto FI = MF.getInfo<WebAssemblyFunctionInfo>();
+    SPReg = FI->getBasePointerVreg();
+  } else if (StackSize) {
+    const TargetRegisterClass *PtrRC =
+        MRI.getTargetRegisterInfo()->getPointerRegClass(MF);
+    Register OffsetReg = MRI.createVirtualRegister(PtrRC);
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcConst(MF)), OffsetReg)
+        .addImm(StackSize);
+    // In the epilog we don't need to write the result back to the SP32/64
+    // physreg because it won't be used again. We can use a stackified register
+    // instead.
+    SPReg = MRI.createVirtualRegister(PtrRC);
+    BuildMI(MBB, InsertPt, DL, TII->get(getOpcAdd(MF)), SPReg)
+        .addReg(SPFPReg)
+        .addReg(OffsetReg);
+  } else {
+    SPReg = SPFPReg;
+  }
+
+  writeSPToGlobal(SPReg, MF, MBB, InsertPt, DL);
+}
+
+bool WebAssemblyFrameLowering::isSupportedStackID(
+    TargetStackID::Value ID) const {
+  // Use the Object stack for WebAssembly locals which can only be accessed
+  // by name, not via an address in linear memory.
+  if (ID == TargetStackID::WasmLocal)
+    return true;
+
+  return TargetFrameLowering::isSupportedStackID(ID);
+}
+
+TargetFrameLowering::DwarfFrameBase
+WebAssemblyFrameLowering::getDwarfFrameBase(const MachineFunction &MF) const {
+  DwarfFrameBase Loc;
+  Loc.Kind = DwarfFrameBase::WasmFrameBase;
+  const WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
+  if (needsSP(MF) && MFI.isFrameBaseVirtual()) {
+    unsigned LocalNum = MFI.getFrameBaseLocal();
+    Loc.Location.WasmLoc = {WebAssembly::TI_LOCAL, LocalNum};
+  } else {
+    // TODO: This should work on a breakpoint at a function with no frame,
+    // but probably won't work for traversing up the stack.
+    Loc.Location.WasmLoc = {WebAssembly::TI_GLOBAL_RELOC, 0};
+  }
+  return Loc;
+}