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Split `Metadata` away from the `Value` class hierarchy, as part of PR21532. Assembly and bitcode changes are in the wings, but this is the bulk of the change for the IR C++ API. I have a follow-up patch prepared for `clang`. If this breaks other sub-projects, I apologize in advance :(. Help me compile it on Darwin I'll try to fix it. FWIW, the errors should be easy to fix, so it may be simpler to just fix it yourself. This breaks the build for all metadata-related code that's out-of-tree. Rest assured the transition is mechanical and the compiler should catch almost all of the problems. Here's a quick guide for updating your code: - `Metadata` is the root of a class hierarchy with three main classes: `MDNode`, `MDString`, and `ValueAsMetadata`. It is distinct from the `Value` class hierarchy. It is typeless -- i.e., instances do *not* have a `Type`. - `MDNode`'s operands are all `Metadata *` (instead of `Value *`). - `TrackingVH<MDNode>` and `WeakVH` referring to metadata can be replaced with `TrackingMDNodeRef` and `TrackingMDRef`, respectively. If you're referring solely to resolved `MDNode`s -- post graph construction -- just use `MDNode*`. - `MDNode` (and the rest of `Metadata`) have only limited support for `replaceAllUsesWith()`. As long as an `MDNode` is pointing at a forward declaration -- the result of `MDNode::getTemporary()` -- it maintains a side map of its uses and can RAUW itself. Once the forward declarations are fully resolved RAUW support is dropped on the ground. This means that uniquing collisions on changing operands cause nodes to become "distinct". (This already happened fairly commonly, whenever an operand went to null.) If you're constructing complex (non self-reference) `MDNode` cycles, you need to call `MDNode::resolveCycles()` on each node (or on a top-level node that somehow references all of the nodes). Also, don't do that. Metadata cycles (and the RAUW machinery needed to construct them) are expensive. - An `MDNode` can only refer to a `Constant` through a bridge called `ConstantAsMetadata` (one of the subclasses of `ValueAsMetadata`). As a side effect, accessing an operand of an `MDNode` that is known to be, e.g., `ConstantInt`, takes three steps: first, cast from `Metadata` to `ConstantAsMetadata`; second, extract the `Constant`; third, cast down to `ConstantInt`. The eventual goal is to introduce `MDInt`/`MDFloat`/etc. and have metadata schema owners transition away from using `Constant`s when the type isn't important (and they don't care about referring to `GlobalValue`s). In the meantime, I've added transitional API to the `mdconst` namespace that matches semantics with the old code, in order to avoid adding the error-prone three-step equivalent to every call site. If your old code was: MDNode *N = foo(); bar(isa <ConstantInt>(N->getOperand(0))); baz(cast <ConstantInt>(N->getOperand(1))); bak(cast_or_null <ConstantInt>(N->getOperand(2))); bat(dyn_cast <ConstantInt>(N->getOperand(3))); bay(dyn_cast_or_null<ConstantInt>(N->getOperand(4))); you can trivially match its semantics with: MDNode *N = foo(); bar(mdconst::hasa <ConstantInt>(N->getOperand(0))); baz(mdconst::extract <ConstantInt>(N->getOperand(1))); bak(mdconst::extract_or_null <ConstantInt>(N->getOperand(2))); bat(mdconst::dyn_extract <ConstantInt>(N->getOperand(3))); bay(mdconst::dyn_extract_or_null<ConstantInt>(N->getOperand(4))); and when you transition your metadata schema to `MDInt`: MDNode *N = foo(); bar(isa <MDInt>(N->getOperand(0))); baz(cast <MDInt>(N->getOperand(1))); bak(cast_or_null <MDInt>(N->getOperand(2))); bat(dyn_cast <MDInt>(N->getOperand(3))); bay(dyn_cast_or_null<MDInt>(N->getOperand(4))); - A `CallInst` -- specifically, intrinsic instructions -- can refer to metadata through a bridge called `MetadataAsValue`. This is a subclass of `Value` where `getType()->isMetadataTy()`. `MetadataAsValue` is the *only* class that can legally refer to a `LocalAsMetadata`, which is a bridged form of non-`Constant` values like `Argument` and `Instruction`. It can also refer to any other `Metadata` subclass. (I'll break all your testcases in a follow-up commit, when I propagate this change to assembly.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223802 91177308-0d34-0410-b5e6-96231b3b80d8
163 lines
6.0 KiB
C++
163 lines
6.0 KiB
C++
//===---- llvm/MDBuilder.cpp - Builder for LLVM metadata ------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the MDBuilder class, which is used as a convenient way to
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// create LLVM metadata with a consistent and simplified interface.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/Metadata.h"
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using namespace llvm;
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MDString *MDBuilder::createString(StringRef Str) {
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return MDString::get(Context, Str);
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}
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ConstantAsMetadata *MDBuilder::createConstant(Constant *C) {
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return ConstantAsMetadata::get(C);
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}
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MDNode *MDBuilder::createFPMath(float Accuracy) {
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if (Accuracy == 0.0)
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return nullptr;
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assert(Accuracy > 0.0 && "Invalid fpmath accuracy!");
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auto *Op =
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createConstant(ConstantFP::get(Type::getFloatTy(Context), Accuracy));
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return MDNode::get(Context, Op);
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}
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MDNode *MDBuilder::createBranchWeights(uint32_t TrueWeight,
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uint32_t FalseWeight) {
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uint32_t Weights[] = {TrueWeight, FalseWeight};
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return createBranchWeights(Weights);
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}
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MDNode *MDBuilder::createBranchWeights(ArrayRef<uint32_t> Weights) {
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assert(Weights.size() >= 2 && "Need at least two branch weights!");
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SmallVector<Metadata *, 4> Vals(Weights.size() + 1);
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Vals[0] = createString("branch_weights");
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Type *Int32Ty = Type::getInt32Ty(Context);
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for (unsigned i = 0, e = Weights.size(); i != e; ++i)
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Vals[i + 1] = createConstant(ConstantInt::get(Int32Ty, Weights[i]));
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return MDNode::get(Context, Vals);
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}
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MDNode *MDBuilder::createRange(const APInt &Lo, const APInt &Hi) {
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assert(Lo.getBitWidth() == Hi.getBitWidth() && "Mismatched bitwidths!");
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// If the range is everything then it is useless.
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if (Hi == Lo)
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return nullptr;
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// Return the range [Lo, Hi).
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Type *Ty = IntegerType::get(Context, Lo.getBitWidth());
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Metadata *Range[2] = {createConstant(ConstantInt::get(Ty, Lo)),
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createConstant(ConstantInt::get(Ty, Hi))};
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return MDNode::get(Context, Range);
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}
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MDNode *MDBuilder::createAnonymousAARoot(StringRef Name, MDNode *Extra) {
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// To ensure uniqueness the root node is self-referential.
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MDNode *Dummy = MDNode::getTemporary(Context, None);
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SmallVector<Metadata *, 3> Args(1, Dummy);
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if (Extra)
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Args.push_back(Extra);
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if (!Name.empty())
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Args.push_back(createString(Name));
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MDNode *Root = MDNode::get(Context, Args);
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// At this point we have
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// !0 = metadata !{} <- dummy
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// !1 = metadata !{metadata !0} <- root
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// Replace the dummy operand with the root node itself and delete the dummy.
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Root->replaceOperandWith(0, Root);
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MDNode::deleteTemporary(Dummy);
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// We now have
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// !1 = metadata !{metadata !1} <- self-referential root
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return Root;
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}
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MDNode *MDBuilder::createTBAARoot(StringRef Name) {
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return MDNode::get(Context, createString(Name));
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}
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/// \brief Return metadata for a non-root TBAA node with the given name,
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/// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
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MDNode *MDBuilder::createTBAANode(StringRef Name, MDNode *Parent,
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bool isConstant) {
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if (isConstant) {
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Constant *Flags = ConstantInt::get(Type::getInt64Ty(Context), 1);
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Metadata *Ops[3] = {createString(Name), Parent, createConstant(Flags)};
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return MDNode::get(Context, Ops);
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} else {
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Metadata *Ops[2] = {createString(Name), Parent};
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return MDNode::get(Context, Ops);
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}
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}
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MDNode *MDBuilder::createAliasScopeDomain(StringRef Name) {
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return MDNode::get(Context, createString(Name));
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}
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MDNode *MDBuilder::createAliasScope(StringRef Name, MDNode *Domain) {
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Metadata *Ops[2] = {createString(Name), Domain};
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return MDNode::get(Context, Ops);
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}
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/// \brief Return metadata for a tbaa.struct node with the given
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/// struct field descriptions.
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MDNode *MDBuilder::createTBAAStructNode(ArrayRef<TBAAStructField> Fields) {
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SmallVector<Metadata *, 4> Vals(Fields.size() * 3);
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Type *Int64 = Type::getInt64Ty(Context);
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for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
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Vals[i * 3 + 0] = createConstant(ConstantInt::get(Int64, Fields[i].Offset));
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Vals[i * 3 + 1] = createConstant(ConstantInt::get(Int64, Fields[i].Size));
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Vals[i * 3 + 2] = Fields[i].TBAA;
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}
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return MDNode::get(Context, Vals);
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}
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/// \brief Return metadata for a TBAA struct node in the type DAG
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/// with the given name, a list of pairs (offset, field type in the type DAG).
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MDNode *MDBuilder::createTBAAStructTypeNode(
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StringRef Name, ArrayRef<std::pair<MDNode *, uint64_t>> Fields) {
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SmallVector<Metadata *, 4> Ops(Fields.size() * 2 + 1);
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Type *Int64 = Type::getInt64Ty(Context);
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Ops[0] = createString(Name);
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for (unsigned i = 0, e = Fields.size(); i != e; ++i) {
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Ops[i * 2 + 1] = Fields[i].first;
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Ops[i * 2 + 2] = createConstant(ConstantInt::get(Int64, Fields[i].second));
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}
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return MDNode::get(Context, Ops);
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}
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/// \brief Return metadata for a TBAA scalar type node with the
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/// given name, an offset and a parent in the TBAA type DAG.
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MDNode *MDBuilder::createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
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uint64_t Offset) {
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ConstantInt *Off = ConstantInt::get(Type::getInt64Ty(Context), Offset);
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Metadata *Ops[3] = {createString(Name), Parent, createConstant(Off)};
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return MDNode::get(Context, Ops);
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}
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/// \brief Return metadata for a TBAA tag node with the given
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/// base type, access type and offset relative to the base type.
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MDNode *MDBuilder::createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
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uint64_t Offset) {
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Type *Int64 = Type::getInt64Ty(Context);
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Metadata *Ops[3] = {BaseType, AccessType,
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createConstant(ConstantInt::get(Int64, Offset))};
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return MDNode::get(Context, Ops);
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}
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