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IR: Split Metadata from Value

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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
This commit is contained in:
Duncan P. N. Exon Smith
2014-12-09 18:38:53 +00:00
parent db7b69e3a6
commit dad20b2ae2
88 changed files with 3370 additions and 1970 deletions
Download Patch File Download Diff File Expand all files Collapse all files

91
lib/IR/DebugInfo.cpp
View File

@ -52,7 +52,7 @@ bool DIDescriptor::Verify() const {
DIImportedEntity(DbgNode).Verify() || DIExpression(DbgNode).Verify());
}
static Value *getField(const MDNode *DbgNode, unsigned Elt) {
static Metadata *getField(const MDNode *DbgNode, unsigned Elt) {
if (!DbgNode || Elt >= DbgNode->getNumOperands())
return nullptr;
return DbgNode->getOperand(Elt);
@ -73,25 +73,17 @@ StringRef DIDescriptor::getStringField(unsigned Elt) const {
}
uint64_t DIDescriptor::getUInt64Field(unsigned Elt) const {
if (!DbgNode)
return 0;
if (Elt < DbgNode->getNumOperands())
if (ConstantInt *CI =
dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
if (auto *C = getConstantField(Elt))
if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
return CI->getZExtValue();
return 0;
}
int64_t DIDescriptor::getInt64Field(unsigned Elt) const {
if (!DbgNode)
return 0;
if (Elt < DbgNode->getNumOperands())
if (ConstantInt *CI =
dyn_cast_or_null<ConstantInt>(DbgNode->getOperand(Elt)))
return CI->getSExtValue();
if (auto *C = getConstantField(Elt))
if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
return CI->getZExtValue();
return 0;
}
@ -102,12 +94,7 @@ DIDescriptor DIDescriptor::getDescriptorField(unsigned Elt) const {
}
GlobalVariable *DIDescriptor::getGlobalVariableField(unsigned Elt) const {
if (!DbgNode)
return nullptr;
if (Elt < DbgNode->getNumOperands())
return dyn_cast_or_null<GlobalVariable>(DbgNode->getOperand(Elt));
return nullptr;
return dyn_cast_or_null<GlobalVariable>(getConstantField(Elt));
}
Constant *DIDescriptor::getConstantField(unsigned Elt) const {
@ -115,17 +102,14 @@ Constant *DIDescriptor::getConstantField(unsigned Elt) const {
return nullptr;
if (Elt < DbgNode->getNumOperands())
return dyn_cast_or_null<Constant>(DbgNode->getOperand(Elt));
if (auto *C =
dyn_cast_or_null<ConstantAsMetadata>(DbgNode->getOperand(Elt)))
return C->getValue();
return nullptr;
}
Function *DIDescriptor::getFunctionField(unsigned Elt) const {
if (!DbgNode)
return nullptr;
if (Elt < DbgNode->getNumOperands())
return dyn_cast_or_null<Function>(DbgNode->getOperand(Elt));
return nullptr;
return dyn_cast_or_null<Function>(getConstantField(Elt));
}
void DIDescriptor::replaceFunctionField(unsigned Elt, Function *F) {
@ -134,7 +118,7 @@ void DIDescriptor::replaceFunctionField(unsigned Elt, Function *F) {
if (Elt < DbgNode->getNumOperands()) {
MDNode *Node = const_cast<MDNode *>(DbgNode);
Node->replaceOperandWith(Elt, F);
Node->replaceOperandWith(Elt, F ? ConstantAsMetadata::get(F) : nullptr);
}
}
@ -347,27 +331,23 @@ void DIDescriptor::replaceAllUsesWith(LLVMContext &VMContext, DIDescriptor D) {
// itself.
const MDNode *DN = D;
if (DbgNode == DN) {
SmallVector<Value*, 10> Ops(DbgNode->getNumOperands());
SmallVector<Metadata *, 10> Ops(DbgNode->getNumOperands());
for (size_t i = 0; i != Ops.size(); ++i)
Ops[i] = DbgNode->getOperand(i);
DN = MDNode::get(VMContext, Ops);
}
MDNode *Node = const_cast<MDNode *>(DbgNode);
const Value *V = cast_or_null<Value>(DN);
Node->replaceAllUsesWith(const_cast<Value *>(V));
auto *Node = cast<MDNodeFwdDecl>(const_cast<MDNode *>(DbgNode));
Node->replaceAllUsesWith(const_cast<MDNode *>(DN));
MDNode::deleteTemporary(Node);
DbgNode = DN;
}
void DIDescriptor::replaceAllUsesWith(MDNode *D) {
assert(DbgNode && "Trying to replace an unverified type!");
assert(DbgNode != D && "This replacement should always happen");
MDNode *Node = const_cast<MDNode *>(DbgNode);
const MDNode *DN = D;
const Value *V = cast_or_null<Value>(DN);
Node->replaceAllUsesWith(const_cast<Value *>(V));
auto *Node = cast<MDNodeFwdDecl>(const_cast<MDNode *>(DbgNode));
Node->replaceAllUsesWith(D);
MDNode::deleteTemporary(Node);
}
@ -398,7 +378,7 @@ bool DIObjCProperty::Verify() const {
static bool fieldIsMDNode(const MDNode *DbgNode, unsigned Elt) {
// FIXME: This function should return true, if the field is null or the field
// is indeed a MDNode: return !Fld || isa<MDNode>(Fld).
Value *Fld = getField(DbgNode, Elt);
Metadata *Fld = getField(DbgNode, Elt);
if (Fld && isa<MDString>(Fld) && !cast<MDString>(Fld)->getString().empty())
return false;
return true;
@ -406,7 +386,7 @@ static bool fieldIsMDNode(const MDNode *DbgNode, unsigned Elt) {
/// \brief Check if a field at position Elt of a MDNode is a MDString.
static bool fieldIsMDString(const MDNode *DbgNode, unsigned Elt) {
Value *Fld = getField(DbgNode, Elt);
Metadata *Fld = getField(DbgNode, Elt);
return !Fld || isa<MDString>(Fld);
}
@ -533,7 +513,6 @@ bool DISubprogram::Verify() const {
// If a DISubprogram has an llvm::Function*, then scope chains from all
// instructions within the function should lead to this DISubprogram.
if (auto *F = getFunction()) {
LLVMContext &Ctxt = F->getContext();
for (auto &BB : *F) {
for (auto &I : BB) {
DebugLoc DL = I.getDebugLoc();
@ -543,15 +522,15 @@ bool DISubprogram::Verify() const {
MDNode *Scope = nullptr;
MDNode *IA = nullptr;
// walk the inlined-at scopes
while (DL.getScopeAndInlinedAt(Scope, IA, F->getContext()), IA)
while ((IA = DL.getInlinedAt()))
DL = DebugLoc::getFromDILocation(IA);
DL.getScopeAndInlinedAt(Scope, IA, Ctxt);
DL.getScopeAndInlinedAt(Scope, IA);
assert(!IA);
while (!DIDescriptor(Scope).isSubprogram()) {
DILexicalBlockFile D(Scope);
Scope = D.isLexicalBlockFile()
? D.getScope()
: DebugLoc::getFromDILexicalBlock(Scope).getScope(Ctxt);
: DebugLoc::getFromDILexicalBlock(Scope).getScope();
}
if (!DISubprogram(Scope).describes(F))
return false;
@ -678,7 +657,7 @@ MDString *DICompositeType::getIdentifier() const {
static void VerifySubsetOf(const MDNode *LHS, const MDNode *RHS) {
for (unsigned i = 0; i != LHS->getNumOperands(); ++i) {
// Skip the 'empty' list (that's a single i32 0, rather than truly empty).
if (i == 0 && isa<ConstantInt>(LHS->getOperand(i)))
if (i == 0 && mdconst::hasa<ConstantInt>(LHS->getOperand(i)))
continue;
const MDNode *E = cast<MDNode>(LHS->getOperand(i));
bool found = false;
@ -690,7 +669,7 @@ static void VerifySubsetOf(const MDNode *LHS, const MDNode *RHS) {
#endif
void DICompositeType::setArraysHelper(MDNode *Elements, MDNode *TParams) {
TrackingVH<MDNode> N(*this);
TrackingMDNodeRef N(*this);
if (Elements) {
#ifndef NDEBUG
// Check that the new list of members contains all the old members as well.
@ -714,7 +693,7 @@ DIScopeRef DIScope::getRef() const {
}
void DICompositeType::setContainingType(DICompositeType ContainingType) {
TrackingVH<MDNode> N(*this);
TrackingMDNodeRef N(*this);
N->replaceOperandWith(5, ContainingType.getRef());
DbgNode = N;
}
@ -748,8 +727,8 @@ DIArray DISubprogram::getVariables() const {
return DIArray(getNodeField(DbgNode, 8));
}
Value *DITemplateValueParameter::getValue() const {
return getField(DbgNode, 3);
Metadata *DITemplateValueParameter::getValue() const {
return DbgNode->getOperand(3);
}
DIScopeRef DIScope::getContext() const {
@ -851,7 +830,7 @@ void DICompileUnit::replaceGlobalVariables(DIArray GlobalVariables) {
DILocation DILocation::copyWithNewScope(LLVMContext &Ctx,
DILexicalBlockFile NewScope) {
SmallVector<Value *, 10> Elts;
SmallVector<Metadata *, 10> Elts;
assert(Verify());
for (unsigned I = 0; I < DbgNode->getNumOperands(); ++I) {
if (I != 2)
@ -875,7 +854,7 @@ DIVariable llvm::createInlinedVariable(MDNode *DV, MDNode *InlinedScope,
return cleanseInlinedVariable(DV, VMContext);
// Insert inlined scope.
SmallVector<Value *, 8> Elts;
SmallVector<Metadata *, 8> Elts;
for (unsigned I = 0, E = DIVariableInlinedAtIndex; I != E; ++I)
Elts.push_back(DV->getOperand(I));
Elts.push_back(InlinedScope);
@ -891,7 +870,7 @@ DIVariable llvm::cleanseInlinedVariable(MDNode *DV, LLVMContext &VMContext) {
return DIVariable(DV);
// Remove inlined scope.
SmallVector<Value *, 8> Elts;
SmallVector<Metadata *, 8> Elts;
for (unsigned I = 0, E = DIVariableInlinedAtIndex; I != E; ++I)
Elts.push_back(DV->getOperand(I));
@ -923,7 +902,7 @@ DISubprogram llvm::getDISubprogram(const Function *F) {
if (Inst == BB.end())
continue;
DebugLoc DLoc = Inst->getDebugLoc();
const MDNode *Scope = DLoc.getScopeNode(F->getParent()->getContext());
const MDNode *Scope = DLoc.getScopeNode();
DISubprogram Subprogram = getDISubprogram(Scope);
return Subprogram.describes(F) ? Subprogram : DISubprogram();
}
@ -1533,10 +1512,10 @@ bool llvm::StripDebugInfo(Module &M) {
}
unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
Value *Val = M.getModuleFlag("Debug Info Version");
if (!Val)
return 0;
return cast<ConstantInt>(Val)->getZExtValue();
if (auto *Val = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("Debug Info Version")))
return Val->getZExtValue();
return 0;
}
llvm::DenseMap<const llvm::Function *, llvm::DISubprogram>