1//===-- WebAssemblyMCLowerPrePass.cpp - Prepare for MC lower --------------===//
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/// \file
10/// Some information in MC lowering / asm printing gets generated as
11/// instructions get emitted, but may be necessary at the start, such as for
12/// .globaltype declarations. This pass collects this information.
13///
14//===----------------------------------------------------------------------===//
15
16#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
17#include "WebAssembly.h"
18#include "WebAssemblyMachineFunctionInfo.h"
19#include "WebAssemblySubtarget.h"
20#include "WebAssemblyUtilities.h"
21#include "llvm/ADT/SCCIterator.h"
22#include "llvm/CodeGen/MachineFrameInfo.h"
23#include "llvm/CodeGen/MachineFunction.h"
24#include "llvm/CodeGen/MachineInstrBuilder.h"
25#include "llvm/CodeGen/MachineLoopInfo.h"
26#include "llvm/CodeGen/MachineModuleInfoImpls.h"
27#include "llvm/CodeGen/MachineRegisterInfo.h"
28#include "llvm/CodeGen/Passes.h"
29#include "llvm/IR/Module.h"
30#include "llvm/Support/Debug.h"
31#include "llvm/Support/raw_ostream.h"
32using namespace llvm;
33
34#define DEBUG_TYPE "wasm-mclower-prepass"
35
36namespace {
37class WebAssemblyMCLowerPrePass final : public ModulePass {
38 StringRef getPassName() const override {
39 return "WebAssembly MC Lower Pre Pass";
40 }
41
42 void getAnalysisUsage(AnalysisUsage &AU) const override {
43 AU.setPreservesCFG();
44 ModulePass::getAnalysisUsage(AU);
45 }
46
47 bool runOnModule(Module &M) override;
48
49public:
50 static char ID; // Pass identification, replacement for typeid
51 WebAssemblyMCLowerPrePass() : ModulePass(ID) {}
52};
53} // end anonymous namespace
54
55char WebAssemblyMCLowerPrePass::ID = 0;
56INITIALIZE_PASS(
57 WebAssemblyMCLowerPrePass, DEBUG_TYPE,
58 "Collects information ahead of time for MC lowering",
59 false, false)
60
61ModulePass *llvm::createWebAssemblyMCLowerPrePass() {
62 return new WebAssemblyMCLowerPrePass();
63}
64
65// NOTE: this is a ModulePass since we need to enforce that this code has run
66// for all functions before AsmPrinter. If this way of doing things is ever
67// suboptimal, we could opt to make it a MachineFunctionPass and instead use
68// something like createBarrierNoopPass() to enforce ordering.
69//
70// The information stored here is essential for emitExternalDecls in the Wasm
71// AsmPrinter
72bool WebAssemblyMCLowerPrePass::runOnModule(Module &M) {
73 auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>();
74 if (!MMIWP)
75 return true;
76
77 MachineModuleInfo &MMI = MMIWP->getMMI();
78 MachineModuleInfoWasm &MMIW = MMI.getObjFileInfo<MachineModuleInfoWasm>();
79
80 for (Function &F : M) {
81 MachineFunction *MF = MMI.getMachineFunction(F);
82 if (!MF)
83 continue;
84
85 LLVM_DEBUG(dbgs() << "********** MC Lower Pre Pass **********\n"
86 "********** Function: "
87 << MF->getName() << '\n');
88
89 for (MachineBasicBlock &MBB : *MF) {
90 for (auto &MI : MBB) {
91 // FIXME: what should all be filtered out beyond these?
92 if (MI.isDebugInstr() || MI.isInlineAsm())
93 continue;
94 for (MachineOperand &MO : MI.uses()) {
95 if (MO.isSymbol()) {
96 MMIW.MachineSymbolsUsed.insert(X: MO.getSymbolName());
97 }
98 }
99 }
100 }
101 }
102 return true;
103}
104