LLVM 19.0.0git
PatchableFunction.cpp
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1//===-- PatchableFunction.cpp - Patchable prologues for LLVM -------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements edits function bodies in place to support the
10// "patchable-function" attribute.
11//
12//===----------------------------------------------------------------------===//
13
20#include "llvm/Pass.h"
21#include "llvm/PassRegistry.h"
22
23using namespace llvm;
24
25namespace {
26struct PatchableFunction : public MachineFunctionPass {
27 static char ID; // Pass identification, replacement for typeid
28 PatchableFunction() : MachineFunctionPass(ID) {
30 }
31
35 MachineFunctionProperties::Property::NoVRegs);
36 }
37};
38}
39
40bool PatchableFunction::runOnMachineFunction(MachineFunction &MF) {
41 MachineBasicBlock &FirstMBB = *MF.begin();
42
43 if (MF.getFunction().hasFnAttribute("patchable-function-entry")) {
45 // The initial .loc covers PATCHABLE_FUNCTION_ENTER.
46 BuildMI(FirstMBB, FirstMBB.begin(), DebugLoc(),
47 TII->get(TargetOpcode::PATCHABLE_FUNCTION_ENTER));
48 return true;
49 } else if (MF.getFunction().hasFnAttribute("patchable-function")) {
50#ifndef NDEBUG
51 Attribute PatchAttr = MF.getFunction().getFnAttribute("patchable-function");
52 StringRef PatchType = PatchAttr.getValueAsString();
53 assert(PatchType == "prologue-short-redirect" && "Only possibility today!");
54#endif
55 auto *TII = MF.getSubtarget().getInstrInfo();
56 BuildMI(FirstMBB, FirstMBB.begin(), DebugLoc(),
57 TII->get(TargetOpcode::PATCHABLE_OP))
58 .addImm(2);
59 MF.ensureAlignment(Align(16));
60 return true;
61 }
62 return false;
63}
64
65char PatchableFunction::ID = 0;
66char &llvm::PatchableFunctionID = PatchableFunction::ID;
67INITIALIZE_PASS(PatchableFunction, "patchable-function",
68 "Implement the 'patchable-function' attribute", false, false)
const HexagonInstrInfo * TII
#define F(x, y, z)
Definition: MD5.cpp:55
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:38
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
StringRef getValueAsString() const
Return the attribute's value as a string.
Definition: Attributes.cpp:349
A debug info location.
Definition: DebugLoc.h:33
Attribute getFnAttribute(Attribute::AttrKind Kind) const
Return the attribute for the given attribute kind.
Definition: Function.cpp:706
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.cpp:680
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
virtual bool runOnMachineFunction(MachineFunction &MF)=0
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
virtual MachineFunctionProperties getRequiredProperties() const
Properties which a MachineFunction may have at a given point in time.
MachineFunctionProperties & set(Property P)
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
void ensureAlignment(Align A)
ensureAlignment - Make sure the function is at least A bytes aligned.
Function & getFunction()
Return the LLVM function that this machine code represents.
const MachineInstrBuilder & addImm(int64_t Val) const
Add a new immediate operand.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
TargetInstrInfo - Interface to description of machine instruction set.
virtual const TargetInstrInfo * getInstrInfo() const
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
Definition: CallingConv.h:24
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
char & PatchableFunctionID
This pass implements the "patchable-function" attribute.
void initializePatchableFunctionPass(PassRegistry &)
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39