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llvm-project/clang/lib/CodeGen/CGCleanup.h

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//===-- CGCleanup.h - Classes for cleanups IR generation --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These classes support the generation of LLVM IR for cleanups.
//
//===----------------------------------------------------------------------===//
#ifndef CLANG_CODEGEN_CGCLEANUP_H
#define CLANG_CODEGEN_CGCLEANUP_H
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/Instructions.h"
namespace clang {
namespace CodeGen {
class CodeGenFunction;
/// A branch fixup. These are required when emitting a goto to a
/// label which hasn't been emitted yet. The goto is optimistically
/// emitted as a branch to the basic block for the label, and (if it
/// occurs in a scope with non-trivial cleanups) a fixup is added to
/// the innermost cleanup. When a (normal) cleanup is popped, any
/// unresolved fixups in that scope are threaded through the cleanup.
struct BranchFixup {
/// The block containing the terminator which needs to be modified
/// into a switch if this fixup is resolved into the current scope.
/// If null, LatestBranch points directly to the destination.
llvm::BasicBlock *OptimisticBranchBlock;
/// The ultimate destination of the branch.
///
/// This can be set to null to indicate that this fixup was
/// successfully resolved.
llvm::BasicBlock *Destination;
/// The destination index value.
unsigned DestinationIndex;
/// The initial branch of the fixup.
llvm::BranchInst *InitialBranch;
};
template <class T> struct InvariantValue {
typedef T type;
typedef T saved_type;
static bool needsSaving(type value) { return false; }
static saved_type save(CodeGenFunction &CGF, type value) { return value; }
static type restore(CodeGenFunction &CGF, saved_type value) { return value; }
};
/// A metaprogramming class for ensuring that a value will dominate an
/// arbitrary position in a function.
template <class T> struct DominatingValue : InvariantValue<T> {};
template <class T, bool mightBeInstruction =
llvm::is_base_of<llvm::Value, T>::value &&
!llvm::is_base_of<llvm::Constant, T>::value &&
!llvm::is_base_of<llvm::BasicBlock, T>::value>
struct DominatingPointer;
template <class T> struct DominatingPointer<T,false> : InvariantValue<T*> {};
// template <class T> struct DominatingPointer<T,true> at end of file
template <class T> struct DominatingValue<T*> : DominatingPointer<T> {};
enum CleanupKind {
EHCleanup = 0x1,
NormalCleanup = 0x2,
NormalAndEHCleanup = EHCleanup | NormalCleanup,
InactiveCleanup = 0x4,
InactiveEHCleanup = EHCleanup | InactiveCleanup,
InactiveNormalCleanup = NormalCleanup | InactiveCleanup,
InactiveNormalAndEHCleanup = NormalAndEHCleanup | InactiveCleanup
};
/// A stack of scopes which respond to exceptions, including cleanups
/// and catch blocks.
class EHScopeStack {
public:
/// A saved depth on the scope stack. This is necessary because
/// pushing scopes onto the stack invalidates iterators.
class stable_iterator {
friend class EHScopeStack;
/// Offset from StartOfData to EndOfBuffer.
ptrdiff_t Size;
stable_iterator(ptrdiff_t Size) : Size(Size) {}
public:
static stable_iterator invalid() { return stable_iterator(-1); }
stable_iterator() : Size(-1) {}
bool isValid() const { return Size >= 0; }
/// Returns true if this scope encloses I.
/// Returns false if I is invalid.
/// This scope must be valid.
bool encloses(stable_iterator I) const { return Size <= I.Size; }
/// Returns true if this scope strictly encloses I: that is,
/// if it encloses I and is not I.
/// Returns false is I is invalid.
/// This scope must be valid.
bool strictlyEncloses(stable_iterator I) const { return Size < I.Size; }
friend bool operator==(stable_iterator A, stable_iterator B) {
return A.Size == B.Size;
}
friend bool operator!=(stable_iterator A, stable_iterator B) {
return A.Size != B.Size;
}
};
/// Information for lazily generating a cleanup. Subclasses must be
/// POD-like: cleanups will not be destructed, and they will be
/// allocated on the cleanup stack and freely copied and moved
/// around.
///
/// Cleanup implementations should generally be declared in an
/// anonymous namespace.
class Cleanup {
// Anchor the construction vtable.
virtual void anchor();
public:
/// Generation flags.
class Flags {
enum {
F_IsForEH = 0x1,
F_IsNormalCleanupKind = 0x2,
F_IsEHCleanupKind = 0x4
};
unsigned flags;
public:
Flags() : flags(0) {}
/// isForEH - true if the current emission is for an EH cleanup.
bool isForEHCleanup() const { return flags & F_IsForEH; }
bool isForNormalCleanup() const { return !isForEHCleanup(); }
void setIsForEHCleanup() { flags |= F_IsForEH; }
bool isNormalCleanupKind() const { return flags & F_IsNormalCleanupKind; }
void setIsNormalCleanupKind() { flags |= F_IsNormalCleanupKind; }
/// isEHCleanupKind - true if the cleanup was pushed as an EH
/// cleanup.
bool isEHCleanupKind() const { return flags & F_IsEHCleanupKind; }
void setIsEHCleanupKind() { flags |= F_IsEHCleanupKind; }
};
// Provide a virtual destructor to suppress a very common warning
// that unfortunately cannot be suppressed without this. Cleanups
// should not rely on this destructor ever being called.
virtual ~Cleanup() {}
/// Emit the cleanup. For normal cleanups, this is run in the
/// same EH context as when the cleanup was pushed, i.e. the
/// immediately-enclosing context of the cleanup scope. For
/// EH cleanups, this is run in a terminate context.
///
// \param flags cleanup kind.
virtual void Emit(CodeGenFunction &CGF, Flags flags) = 0;
};
/// ConditionalCleanupN stores the saved form of its N parameters,
/// then restores them and performs the cleanup.
template <class T, class A0>
class ConditionalCleanup1 : public Cleanup {
typedef typename DominatingValue<A0>::saved_type A0_saved;
A0_saved a0_saved;
void Emit(CodeGenFunction &CGF, Flags flags) {
A0 a0 = DominatingValue<A0>::restore(CGF, a0_saved);
T(a0).Emit(CGF, flags);
}
public:
ConditionalCleanup1(A0_saved a0)
: a0_saved(a0) {}
};
template <class T, class A0, class A1>
class ConditionalCleanup2 : public Cleanup {
typedef typename DominatingValue<A0>::saved_type A0_saved;
typedef typename DominatingValue<A1>::saved_type A1_saved;
A0_saved a0_saved;
A1_saved a1_saved;
void Emit(CodeGenFunction &CGF, Flags flags) {
A0 a0 = DominatingValue<A0>::restore(CGF, a0_saved);
A1 a1 = DominatingValue<A1>::restore(CGF, a1_saved);
T(a0, a1).Emit(CGF, flags);
}
public:
ConditionalCleanup2(A0_saved a0, A1_saved a1)
: a0_saved(a0), a1_saved(a1) {}
};
template <class T, class A0, class A1, class A2>
class ConditionalCleanup3 : public Cleanup {
typedef typename DominatingValue<A0>::saved_type A0_saved;
typedef typename DominatingValue<A1>::saved_type A1_saved;
typedef typename DominatingValue<A2>::saved_type A2_saved;
A0_saved a0_saved;
A1_saved a1_saved;
A2_saved a2_saved;
void Emit(CodeGenFunction &CGF, Flags flags) {
A0 a0 = DominatingValue<A0>::restore(CGF, a0_saved);
A1 a1 = DominatingValue<A1>::restore(CGF, a1_saved);
A2 a2 = DominatingValue<A2>::restore(CGF, a2_saved);
T(a0, a1, a2).Emit(CGF, flags);
}
public:
ConditionalCleanup3(A0_saved a0, A1_saved a1, A2_saved a2)
: a0_saved(a0), a1_saved(a1), a2_saved(a2) {}
};
template <class T, class A0, class A1, class A2, class A3>
class ConditionalCleanup4 : public Cleanup {
typedef typename DominatingValue<A0>::saved_type A0_saved;
typedef typename DominatingValue<A1>::saved_type A1_saved;
typedef typename DominatingValue<A2>::saved_type A2_saved;
typedef typename DominatingValue<A3>::saved_type A3_saved;
A0_saved a0_saved;
A1_saved a1_saved;
A2_saved a2_saved;
A3_saved a3_saved;
void Emit(CodeGenFunction &CGF, Flags flags) {
A0 a0 = DominatingValue<A0>::restore(CGF, a0_saved);
A1 a1 = DominatingValue<A1>::restore(CGF, a1_saved);
A2 a2 = DominatingValue<A2>::restore(CGF, a2_saved);
A3 a3 = DominatingValue<A3>::restore(CGF, a3_saved);
T(a0, a1, a2, a3).Emit(CGF, flags);
}
public:
ConditionalCleanup4(A0_saved a0, A1_saved a1, A2_saved a2, A3_saved a3)
: a0_saved(a0), a1_saved(a1), a2_saved(a2), a3_saved(a3) {}
};
private:
// The implementation for this class is in CGException.h and
// CGException.cpp; the definition is here because it's used as a
// member of CodeGenFunction.
/// The start of the scope-stack buffer, i.e. the allocated pointer
/// for the buffer. All of these pointers are either simultaneously
/// null or simultaneously valid.
char *StartOfBuffer;
/// The end of the buffer.
char *EndOfBuffer;
/// The first valid entry in the buffer.
char *StartOfData;
/// The innermost normal cleanup on the stack.
stable_iterator InnermostNormalCleanup;
/// The innermost EH scope on the stack.
stable_iterator InnermostEHScope;
/// The current set of branch fixups. A branch fixup is a jump to
/// an as-yet unemitted label, i.e. a label for which we don't yet
/// know the EH stack depth. Whenever we pop a cleanup, we have
/// to thread all the current branch fixups through it.
///
/// Fixups are recorded as the Use of the respective branch or
/// switch statement. The use points to the final destination.
/// When popping out of a cleanup, these uses are threaded through
/// the cleanup and adjusted to point to the new cleanup.
///
/// Note that branches are allowed to jump into protected scopes
/// in certain situations; e.g. the following code is legal:
/// struct A { ~A(); }; // trivial ctor, non-trivial dtor
/// goto foo;
/// A a;
/// foo:
/// bar();
SmallVector<BranchFixup, 8> BranchFixups;
char *allocate(size_t Size);
void *pushCleanup(CleanupKind K, size_t DataSize);
public:
EHScopeStack() : StartOfBuffer(0), EndOfBuffer(0), StartOfData(0),
InnermostNormalCleanup(stable_end()),
InnermostEHScope(stable_end()) {}
~EHScopeStack() { delete[] StartOfBuffer; }
// Variadic templates would make this not terrible.
/// Push a lazily-created cleanup on the stack.
template <class T>
void pushCleanup(CleanupKind Kind) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T();
(void) Obj;
}
/// Push a lazily-created cleanup on the stack.
template <class T, class A0>
void pushCleanup(CleanupKind Kind, A0 a0) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T(a0);
(void) Obj;
}
/// Push a lazily-created cleanup on the stack.
template <class T, class A0, class A1>
void pushCleanup(CleanupKind Kind, A0 a0, A1 a1) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T(a0, a1);
(void) Obj;
}
/// Push a lazily-created cleanup on the stack.
template <class T, class A0, class A1, class A2>
void pushCleanup(CleanupKind Kind, A0 a0, A1 a1, A2 a2) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T(a0, a1, a2);
(void) Obj;
}
/// Push a lazily-created cleanup on the stack.
template <class T, class A0, class A1, class A2, class A3>
void pushCleanup(CleanupKind Kind, A0 a0, A1 a1, A2 a2, A3 a3) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T(a0, a1, a2, a3);
(void) Obj;
}
/// Push a lazily-created cleanup on the stack.
template <class T, class A0, class A1, class A2, class A3, class A4>
void pushCleanup(CleanupKind Kind, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
void *Buffer = pushCleanup(Kind, sizeof(T));
Cleanup *Obj = new(Buffer) T(a0, a1, a2, a3, a4);
(void) Obj;
}
// Feel free to add more variants of the following:
/// Push a cleanup with non-constant storage requirements on the
/// stack. The cleanup type must provide an additional static method:
/// static size_t getExtraSize(size_t);
/// The argument to this method will be the value N, which will also
/// be passed as the first argument to the constructor.
///
/// The data stored in the extra storage must obey the same
/// restrictions as normal cleanup member data.
///
/// The pointer returned from this method is valid until the cleanup
/// stack is modified.
template <class T, class A0, class A1, class A2>
T *pushCleanupWithExtra(CleanupKind Kind, size_t N, A0 a0, A1 a1, A2 a2) {
void *Buffer = pushCleanup(Kind, sizeof(T) + T::getExtraSize(N));
return new (Buffer) T(N, a0, a1, a2);
}
void pushCopyOfCleanup(CleanupKind Kind, const void *Cleanup, size_t Size) {
void *Buffer = pushCleanup(Kind, Size);
std::memcpy(Buffer, Cleanup, Size);
}
/// Pops a cleanup scope off the stack. This is private to CGCleanup.cpp.
void popCleanup();
/// Push a set of catch handlers on the stack. The catch is
/// uninitialized and will need to have the given number of handlers
/// set on it.
class EHCatchScope *pushCatch(unsigned NumHandlers);
/// Pops a catch scope off the stack. This is private to CGException.cpp.
void popCatch();
/// Push an exceptions filter on the stack.
class EHFilterScope *pushFilter(unsigned NumFilters);
/// Pops an exceptions filter off the stack.
void popFilter();
/// Push a terminate handler on the stack.
void pushTerminate();
/// Pops a terminate handler off the stack.
void popTerminate();
/// Determines whether the exception-scopes stack is empty.
bool empty() const { return StartOfData == EndOfBuffer; }
bool requiresLandingPad() const {
return InnermostEHScope != stable_end();
}
/// Determines whether there are any normal cleanups on the stack.
bool hasNormalCleanups() const {
return InnermostNormalCleanup != stable_end();
}
/// Returns the innermost normal cleanup on the stack, or
/// stable_end() if there are no normal cleanups.
stable_iterator getInnermostNormalCleanup() const {
return InnermostNormalCleanup;
}
stable_iterator getInnermostActiveNormalCleanup() const;
stable_iterator getInnermostEHScope() const {
return InnermostEHScope;
}
stable_iterator getInnermostActiveEHScope() const;
/// An unstable reference to a scope-stack depth. Invalidated by
/// pushes but not pops.
class iterator;
/// Returns an iterator pointing to the innermost EH scope.
iterator begin() const;
/// Returns an iterator pointing to the outermost EH scope.
iterator end() const;
/// Create a stable reference to the top of the EH stack. The
/// returned reference is valid until that scope is popped off the
/// stack.
stable_iterator stable_begin() const {
return stable_iterator(EndOfBuffer - StartOfData);
}
/// Create a stable reference to the bottom of the EH stack.
static stable_iterator stable_end() {
return stable_iterator(0);
}
/// Translates an iterator into a stable_iterator.
stable_iterator stabilize(iterator it) const;
/// Turn a stable reference to a scope depth into a unstable pointer
/// to the EH stack.
iterator find(stable_iterator save) const;
/// Removes the cleanup pointed to by the given stable_iterator.
void removeCleanup(stable_iterator save);
/// Add a branch fixup to the current cleanup scope.
BranchFixup &addBranchFixup() {
assert(hasNormalCleanups() && "adding fixup in scope without cleanups");
BranchFixups.push_back(BranchFixup());
return BranchFixups.back();
}
unsigned getNumBranchFixups() const { return BranchFixups.size(); }
BranchFixup &getBranchFixup(unsigned I) {
assert(I < getNumBranchFixups());
return BranchFixups[I];
}
/// Pops lazily-removed fixups from the end of the list. This
/// should only be called by procedures which have just popped a
/// cleanup or resolved one or more fixups.
void popNullFixups();
/// Clears the branch-fixups list. This should only be called by
/// ResolveAllBranchFixups.
void clearFixups() { BranchFixups.clear(); }
};
/// A protected scope for zero-cost EH handling.
class EHScope {
llvm::BasicBlock *CachedLandingPad;
llvm::BasicBlock *CachedEHDispatchBlock;
EHScopeStack::stable_iterator EnclosingEHScope;
class CommonBitFields {
friend class EHScope;
unsigned Kind : 2;
};
enum { NumCommonBits = 2 };
protected:
class CatchBitFields {
friend class EHCatchScope;
unsigned : NumCommonBits;
unsigned NumHandlers : 32 - NumCommonBits;
};
class CleanupBitFields {
friend class EHCleanupScope;
unsigned : NumCommonBits;
/// Whether this cleanup needs to be run along normal edges.
unsigned IsNormalCleanup : 1;
/// Whether this cleanup needs to be run along exception edges.
unsigned IsEHCleanup : 1;
/// Whether this cleanup is currently active.
unsigned IsActive : 1;
/// Whether the normal cleanup should test the activation flag.
unsigned TestFlagInNormalCleanup : 1;
/// Whether the EH cleanup should test the activation flag.
unsigned TestFlagInEHCleanup : 1;
/// The amount of extra storage needed by the Cleanup.
/// Always a multiple of the scope-stack alignment.
unsigned CleanupSize : 12;
/// The number of fixups required by enclosing scopes (not including
/// this one). If this is the top cleanup scope, all the fixups
/// from this index onwards belong to this scope.
unsigned FixupDepth : 32 - 17 - NumCommonBits; // currently 13
};
class FilterBitFields {
friend class EHFilterScope;
unsigned : NumCommonBits;
unsigned NumFilters : 32 - NumCommonBits;
};
union {
CommonBitFields CommonBits;
CatchBitFields CatchBits;
CleanupBitFields CleanupBits;
FilterBitFields FilterBits;
};
public:
enum Kind { Cleanup, Catch, Terminate, Filter };
EHScope(Kind kind, EHScopeStack::stable_iterator enclosingEHScope)
: CachedLandingPad(0), CachedEHDispatchBlock(0),
EnclosingEHScope(enclosingEHScope) {
CommonBits.Kind = kind;
}
Kind getKind() const { return static_cast<Kind>(CommonBits.Kind); }
llvm::BasicBlock *getCachedLandingPad() const {
return CachedLandingPad;
}
void setCachedLandingPad(llvm::BasicBlock *block) {
CachedLandingPad = block;
}
llvm::BasicBlock *getCachedEHDispatchBlock() const {
return CachedEHDispatchBlock;
}
void setCachedEHDispatchBlock(llvm::BasicBlock *block) {
CachedEHDispatchBlock = block;
}
bool hasEHBranches() const {
if (llvm::BasicBlock *block = getCachedEHDispatchBlock())
return !block->use_empty();
return false;
}
EHScopeStack::stable_iterator getEnclosingEHScope() const {
return EnclosingEHScope;
}
};
/// A scope which attempts to handle some, possibly all, types of
/// exceptions.
///
/// Objective C \@finally blocks are represented using a cleanup scope
/// after the catch scope.
class EHCatchScope : public EHScope {
// In effect, we have a flexible array member
// Handler Handlers[0];
// But that's only standard in C99, not C++, so we have to do
// annoying pointer arithmetic instead.
public:
struct Handler {
/// A type info value, or null (C++ null, not an LLVM null pointer)
/// for a catch-all.
llvm::Value *Type;
/// The catch handler for this type.
llvm::BasicBlock *Block;
bool isCatchAll() const { return Type == 0; }
};
private:
friend class EHScopeStack;
Handler *getHandlers() {
return reinterpret_cast<Handler*>(this+1);
}
const Handler *getHandlers() const {
return reinterpret_cast<const Handler*>(this+1);
}
public:
static size_t getSizeForNumHandlers(unsigned N) {
return sizeof(EHCatchScope) + N * sizeof(Handler);
}
EHCatchScope(unsigned numHandlers,
EHScopeStack::stable_iterator enclosingEHScope)
: EHScope(Catch, enclosingEHScope) {
CatchBits.NumHandlers = numHandlers;
}
unsigned getNumHandlers() const {
return CatchBits.NumHandlers;
}
void setCatchAllHandler(unsigned I, llvm::BasicBlock *Block) {
setHandler(I, /*catchall*/ 0, Block);
}
void setHandler(unsigned I, llvm::Value *Type, llvm::BasicBlock *Block) {
assert(I < getNumHandlers());
getHandlers()[I].Type = Type;
getHandlers()[I].Block = Block;
}
const Handler &getHandler(unsigned I) const {
assert(I < getNumHandlers());
return getHandlers()[I];
}
typedef const Handler *iterator;
iterator begin() const { return getHandlers(); }
iterator end() const { return getHandlers() + getNumHandlers(); }
static bool classof(const EHScope *Scope) {
return Scope->getKind() == Catch;
}
};
/// A cleanup scope which generates the cleanup blocks lazily.
class EHCleanupScope : public EHScope {
/// The nearest normal cleanup scope enclosing this one.
EHScopeStack::stable_iterator EnclosingNormal;
/// The nearest EH scope enclosing this one.
EHScopeStack::stable_iterator EnclosingEH;
/// The dual entry/exit block along the normal edge. This is lazily
/// created if needed before the cleanup is popped.
llvm::BasicBlock *NormalBlock;
/// An optional i1 variable indicating whether this cleanup has been
/// activated yet.
llvm::AllocaInst *ActiveFlag;
/// Extra information required for cleanups that have resolved
/// branches through them. This has to be allocated on the side
/// because everything on the cleanup stack has be trivially
/// movable.
struct ExtInfo {
/// The destinations of normal branch-afters and branch-throughs.
llvm::SmallPtrSet<llvm::BasicBlock*, 4> Branches;
/// Normal branch-afters.
SmallVector<std::pair<llvm::BasicBlock*,llvm::ConstantInt*>, 4>
BranchAfters;
};
mutable struct ExtInfo *ExtInfo;
struct ExtInfo &getExtInfo() {
if (!ExtInfo) ExtInfo = new struct ExtInfo();
return *ExtInfo;
}
const struct ExtInfo &getExtInfo() const {
if (!ExtInfo) ExtInfo = new struct ExtInfo();
return *ExtInfo;
}
public:
/// Gets the size required for a lazy cleanup scope with the given
/// cleanup-data requirements.
static size_t getSizeForCleanupSize(size_t Size) {
return sizeof(EHCleanupScope) + Size;
}
size_t getAllocatedSize() const {
return sizeof(EHCleanupScope) + CleanupBits.CleanupSize;
}
EHCleanupScope(bool isNormal, bool isEH, bool isActive,
unsigned cleanupSize, unsigned fixupDepth,
EHScopeStack::stable_iterator enclosingNormal,
EHScopeStack::stable_iterator enclosingEH)
: EHScope(EHScope::Cleanup, enclosingEH), EnclosingNormal(enclosingNormal),
NormalBlock(0), ActiveFlag(0), ExtInfo(0) {
CleanupBits.IsNormalCleanup = isNormal;
CleanupBits.IsEHCleanup = isEH;
CleanupBits.IsActive = isActive;
CleanupBits.TestFlagInNormalCleanup = false;
CleanupBits.TestFlagInEHCleanup = false;
CleanupBits.CleanupSize = cleanupSize;
CleanupBits.FixupDepth = fixupDepth;
assert(CleanupBits.CleanupSize == cleanupSize && "cleanup size overflow");
}
~EHCleanupScope() {
delete ExtInfo;
}
bool isNormalCleanup() const { return CleanupBits.IsNormalCleanup; }
llvm::BasicBlock *getNormalBlock() const { return NormalBlock; }
void setNormalBlock(llvm::BasicBlock *BB) { NormalBlock = BB; }
bool isEHCleanup() const { return CleanupBits.IsEHCleanup; }
llvm::BasicBlock *getEHBlock() const { return getCachedEHDispatchBlock(); }
void setEHBlock(llvm::BasicBlock *BB) { setCachedEHDispatchBlock(BB); }
bool isActive() const { return CleanupBits.IsActive; }
void setActive(bool A) { CleanupBits.IsActive = A; }
llvm::AllocaInst *getActiveFlag() const { return ActiveFlag; }
void setActiveFlag(llvm::AllocaInst *Var) { ActiveFlag = Var; }
void setTestFlagInNormalCleanup() {
CleanupBits.TestFlagInNormalCleanup = true;
}
bool shouldTestFlagInNormalCleanup() const {
return CleanupBits.TestFlagInNormalCleanup;
}
void setTestFlagInEHCleanup() {
CleanupBits.TestFlagInEHCleanup = true;
}
bool shouldTestFlagInEHCleanup() const {
return CleanupBits.TestFlagInEHCleanup;
}
unsigned getFixupDepth() const { return CleanupBits.FixupDepth; }
EHScopeStack::stable_iterator getEnclosingNormalCleanup() const {
return EnclosingNormal;
}
size_t getCleanupSize() const { return CleanupBits.CleanupSize; }
void *getCleanupBuffer() { return this + 1; }
EHScopeStack::Cleanup *getCleanup() {
return reinterpret_cast<EHScopeStack::Cleanup*>(getCleanupBuffer());
}
/// True if this cleanup scope has any branch-afters or branch-throughs.
bool hasBranches() const { return ExtInfo && !ExtInfo->Branches.empty(); }
/// Add a branch-after to this cleanup scope. A branch-after is a
/// branch from a point protected by this (normal) cleanup to a
/// point in the normal cleanup scope immediately containing it.
/// For example,
/// for (;;) { A a; break; }
/// contains a branch-after.
///
/// Branch-afters each have their own destination out of the
/// cleanup, guaranteed distinct from anything else threaded through
/// it. Therefore branch-afters usually force a switch after the
/// cleanup.
void addBranchAfter(llvm::ConstantInt *Index,
llvm::BasicBlock *Block) {
struct ExtInfo &ExtInfo = getExtInfo();
if (ExtInfo.Branches.insert(Block))
ExtInfo.BranchAfters.push_back(std::make_pair(Block, Index));
}
/// Return the number of unique branch-afters on this scope.
unsigned getNumBranchAfters() const {
return ExtInfo ? ExtInfo->BranchAfters.size() : 0;
}
llvm::BasicBlock *getBranchAfterBlock(unsigned I) const {
assert(I < getNumBranchAfters());
return ExtInfo->BranchAfters[I].first;
}
llvm::ConstantInt *getBranchAfterIndex(unsigned I) const {
assert(I < getNumBranchAfters());
return ExtInfo->BranchAfters[I].second;
}
/// Add a branch-through to this cleanup scope. A branch-through is
/// a branch from a scope protected by this (normal) cleanup to an
/// enclosing scope other than the immediately-enclosing normal
/// cleanup scope.
///
/// In the following example, the branch through B's scope is a
/// branch-through, while the branch through A's scope is a
/// branch-after:
/// for (;;) { A a; B b; break; }
///
/// All branch-throughs have a common destination out of the
/// cleanup, one possibly shared with the fall-through. Therefore
/// branch-throughs usually don't force a switch after the cleanup.
///
/// \return true if the branch-through was new to this scope
bool addBranchThrough(llvm::BasicBlock *Block) {
return getExtInfo().Branches.insert(Block);
}
/// Determines if this cleanup scope has any branch throughs.
bool hasBranchThroughs() const {
if (!ExtInfo) return false;
return (ExtInfo->BranchAfters.size() != ExtInfo->Branches.size());
}
static bool classof(const EHScope *Scope) {
return (Scope->getKind() == Cleanup);
}
};
/// An exceptions scope which filters exceptions thrown through it.
/// Only exceptions matching the filter types will be permitted to be
/// thrown.
///
/// This is used to implement C++ exception specifications.
class EHFilterScope : public EHScope {
// Essentially ends in a flexible array member:
// llvm::Value *FilterTypes[0];
llvm::Value **getFilters() {
return reinterpret_cast<llvm::Value**>(this+1);
}
llvm::Value * const *getFilters() const {
return reinterpret_cast<llvm::Value* const *>(this+1);
}
public:
EHFilterScope(unsigned numFilters)
: EHScope(Filter, EHScopeStack::stable_end()) {
FilterBits.NumFilters = numFilters;
}
static size_t getSizeForNumFilters(unsigned numFilters) {
return sizeof(EHFilterScope) + numFilters * sizeof(llvm::Value*);
}
unsigned getNumFilters() const { return FilterBits.NumFilters; }
void setFilter(unsigned i, llvm::Value *filterValue) {
assert(i < getNumFilters());
getFilters()[i] = filterValue;
}
llvm::Value *getFilter(unsigned i) const {
assert(i < getNumFilters());
return getFilters()[i];
}
static bool classof(const EHScope *scope) {
return scope->getKind() == Filter;
}
};
/// An exceptions scope which calls std::terminate if any exception
/// reaches it.
class EHTerminateScope : public EHScope {
public:
EHTerminateScope(EHScopeStack::stable_iterator enclosingEHScope)
: EHScope(Terminate, enclosingEHScope) {}
static size_t getSize() { return sizeof(EHTerminateScope); }
static bool classof(const EHScope *scope) {
return scope->getKind() == Terminate;
}
};
/// A non-stable pointer into the scope stack.
class EHScopeStack::iterator {
char *Ptr;
friend class EHScopeStack;
explicit iterator(char *Ptr) : Ptr(Ptr) {}
public:
iterator() : Ptr(0) {}
EHScope *get() const {
return reinterpret_cast<EHScope*>(Ptr);
}
EHScope *operator->() const { return get(); }
EHScope &operator*() const { return *get(); }
iterator &operator++() {
switch (get()->getKind()) {
case EHScope::Catch:
Ptr += EHCatchScope::getSizeForNumHandlers(
static_cast<const EHCatchScope*>(get())->getNumHandlers());
break;
case EHScope::Filter:
Ptr += EHFilterScope::getSizeForNumFilters(
static_cast<const EHFilterScope*>(get())->getNumFilters());
break;
case EHScope::Cleanup:
Ptr += static_cast<const EHCleanupScope*>(get())
->getAllocatedSize();
break;
case EHScope::Terminate:
Ptr += EHTerminateScope::getSize();
break;
}
return *this;
}
iterator next() {
iterator copy = *this;
++copy;
return copy;
}
iterator operator++(int) {
iterator copy = *this;
operator++();
return copy;
}
bool encloses(iterator other) const { return Ptr >= other.Ptr; }
bool strictlyEncloses(iterator other) const { return Ptr > other.Ptr; }
bool operator==(iterator other) const { return Ptr == other.Ptr; }
bool operator!=(iterator other) const { return Ptr != other.Ptr; }
};
inline EHScopeStack::iterator EHScopeStack::begin() const {
return iterator(StartOfData);
}
inline EHScopeStack::iterator EHScopeStack::end() const {
return iterator(EndOfBuffer);
}
inline void EHScopeStack::popCatch() {
assert(!empty() && "popping exception stack when not empty");
EHCatchScope &scope = cast<EHCatchScope>(*begin());
InnermostEHScope = scope.getEnclosingEHScope();
StartOfData += EHCatchScope::getSizeForNumHandlers(scope.getNumHandlers());
}
inline void EHScopeStack::popTerminate() {
assert(!empty() && "popping exception stack when not empty");
EHTerminateScope &scope = cast<EHTerminateScope>(*begin());
InnermostEHScope = scope.getEnclosingEHScope();
StartOfData += EHTerminateScope::getSize();
}
inline EHScopeStack::iterator EHScopeStack::find(stable_iterator sp) const {
assert(sp.isValid() && "finding invalid savepoint");
assert(sp.Size <= stable_begin().Size && "finding savepoint after pop");
return iterator(EndOfBuffer - sp.Size);
}
inline EHScopeStack::stable_iterator
EHScopeStack::stabilize(iterator ir) const {
assert(StartOfData <= ir.Ptr && ir.Ptr <= EndOfBuffer);
return stable_iterator(EndOfBuffer - ir.Ptr);
}
}
}
#endif
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