Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 1 | //===-- EHScopeStack.h - Stack for cleanup IR generation --------*- C++ -*-===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // These classes should be the minimum interface required for other parts of |
| 11 | // CodeGen to emit cleanups. The implementation is in CGCleanup.cpp and other |
| 12 | // implemenentation details that are not widely needed are in CGCleanup.h. |
| 13 | // |
| 14 | //===----------------------------------------------------------------------===// |
| 15 | |
Stephen Hines | 176edba | 2014-12-01 14:53:08 -0800 | [diff] [blame] | 16 | #ifndef LLVM_CLANG_LIB_CODEGEN_EHSCOPESTACK_H |
| 17 | #define LLVM_CLANG_LIB_CODEGEN_EHSCOPESTACK_H |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 18 | |
| 19 | #include "clang/Basic/LLVM.h" |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 20 | #include "llvm/ADT/STLExtras.h" |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 21 | #include "llvm/ADT/SmallVector.h" |
| 22 | #include "llvm/IR/BasicBlock.h" |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 23 | #include "llvm/IR/Instructions.h" |
Stephen Hines | 651f13c | 2014-04-23 16:59:28 -0700 | [diff] [blame] | 24 | #include "llvm/IR/Value.h" |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 25 | |
| 26 | namespace clang { |
| 27 | namespace CodeGen { |
| 28 | |
| 29 | class CodeGenFunction; |
| 30 | |
| 31 | /// A branch fixup. These are required when emitting a goto to a |
| 32 | /// label which hasn't been emitted yet. The goto is optimistically |
| 33 | /// emitted as a branch to the basic block for the label, and (if it |
| 34 | /// occurs in a scope with non-trivial cleanups) a fixup is added to |
| 35 | /// the innermost cleanup. When a (normal) cleanup is popped, any |
| 36 | /// unresolved fixups in that scope are threaded through the cleanup. |
| 37 | struct BranchFixup { |
| 38 | /// The block containing the terminator which needs to be modified |
| 39 | /// into a switch if this fixup is resolved into the current scope. |
| 40 | /// If null, LatestBranch points directly to the destination. |
| 41 | llvm::BasicBlock *OptimisticBranchBlock; |
| 42 | |
| 43 | /// The ultimate destination of the branch. |
| 44 | /// |
| 45 | /// This can be set to null to indicate that this fixup was |
| 46 | /// successfully resolved. |
| 47 | llvm::BasicBlock *Destination; |
| 48 | |
| 49 | /// The destination index value. |
| 50 | unsigned DestinationIndex; |
| 51 | |
| 52 | /// The initial branch of the fixup. |
| 53 | llvm::BranchInst *InitialBranch; |
| 54 | }; |
| 55 | |
| 56 | template <class T> struct InvariantValue { |
| 57 | typedef T type; |
| 58 | typedef T saved_type; |
| 59 | static bool needsSaving(type value) { return false; } |
| 60 | static saved_type save(CodeGenFunction &CGF, type value) { return value; } |
| 61 | static type restore(CodeGenFunction &CGF, saved_type value) { return value; } |
| 62 | }; |
| 63 | |
| 64 | /// A metaprogramming class for ensuring that a value will dominate an |
| 65 | /// arbitrary position in a function. |
| 66 | template <class T> struct DominatingValue : InvariantValue<T> {}; |
| 67 | |
| 68 | template <class T, bool mightBeInstruction = |
Stephen Hines | 651f13c | 2014-04-23 16:59:28 -0700 | [diff] [blame] | 69 | std::is_base_of<llvm::Value, T>::value && |
| 70 | !std::is_base_of<llvm::Constant, T>::value && |
| 71 | !std::is_base_of<llvm::BasicBlock, T>::value> |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 72 | struct DominatingPointer; |
| 73 | template <class T> struct DominatingPointer<T,false> : InvariantValue<T*> {}; |
| 74 | // template <class T> struct DominatingPointer<T,true> at end of file |
| 75 | |
| 76 | template <class T> struct DominatingValue<T*> : DominatingPointer<T> {}; |
| 77 | |
Stephen Hines | 176edba | 2014-12-01 14:53:08 -0800 | [diff] [blame] | 78 | enum CleanupKind : unsigned { |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 79 | /// Denotes a cleanup that should run when a scope is exited using exceptional |
| 80 | /// control flow (a throw statement leading to stack unwinding, ). |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 81 | EHCleanup = 0x1, |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 82 | |
| 83 | /// Denotes a cleanup that should run when a scope is exited using normal |
| 84 | /// control flow (falling off the end of the scope, return, goto, ...). |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 85 | NormalCleanup = 0x2, |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 86 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 87 | NormalAndEHCleanup = EHCleanup | NormalCleanup, |
| 88 | |
| 89 | InactiveCleanup = 0x4, |
| 90 | InactiveEHCleanup = EHCleanup | InactiveCleanup, |
| 91 | InactiveNormalCleanup = NormalCleanup | InactiveCleanup, |
Pirama Arumuga Nainar | 4967a71 | 2016-09-19 22:19:55 -0700 | [diff] [blame^] | 92 | InactiveNormalAndEHCleanup = NormalAndEHCleanup | InactiveCleanup, |
| 93 | |
| 94 | LifetimeMarker = 0x8, |
| 95 | NormalEHLifetimeMarker = LifetimeMarker | NormalAndEHCleanup, |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 96 | }; |
| 97 | |
| 98 | /// A stack of scopes which respond to exceptions, including cleanups |
| 99 | /// and catch blocks. |
| 100 | class EHScopeStack { |
| 101 | public: |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 102 | /* Should switch to alignof(uint64_t) instead of 8, when EHCleanupScope can */ |
| 103 | enum { ScopeStackAlignment = 8 }; |
| 104 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 105 | /// A saved depth on the scope stack. This is necessary because |
| 106 | /// pushing scopes onto the stack invalidates iterators. |
| 107 | class stable_iterator { |
| 108 | friend class EHScopeStack; |
| 109 | |
| 110 | /// Offset from StartOfData to EndOfBuffer. |
| 111 | ptrdiff_t Size; |
| 112 | |
| 113 | stable_iterator(ptrdiff_t Size) : Size(Size) {} |
| 114 | |
| 115 | public: |
| 116 | static stable_iterator invalid() { return stable_iterator(-1); } |
| 117 | stable_iterator() : Size(-1) {} |
| 118 | |
| 119 | bool isValid() const { return Size >= 0; } |
| 120 | |
| 121 | /// Returns true if this scope encloses I. |
| 122 | /// Returns false if I is invalid. |
| 123 | /// This scope must be valid. |
| 124 | bool encloses(stable_iterator I) const { return Size <= I.Size; } |
| 125 | |
| 126 | /// Returns true if this scope strictly encloses I: that is, |
| 127 | /// if it encloses I and is not I. |
| 128 | /// Returns false is I is invalid. |
| 129 | /// This scope must be valid. |
| 130 | bool strictlyEncloses(stable_iterator I) const { return Size < I.Size; } |
| 131 | |
| 132 | friend bool operator==(stable_iterator A, stable_iterator B) { |
| 133 | return A.Size == B.Size; |
| 134 | } |
| 135 | friend bool operator!=(stable_iterator A, stable_iterator B) { |
| 136 | return A.Size != B.Size; |
| 137 | } |
| 138 | }; |
| 139 | |
| 140 | /// Information for lazily generating a cleanup. Subclasses must be |
| 141 | /// POD-like: cleanups will not be destructed, and they will be |
| 142 | /// allocated on the cleanup stack and freely copied and moved |
| 143 | /// around. |
| 144 | /// |
| 145 | /// Cleanup implementations should generally be declared in an |
| 146 | /// anonymous namespace. |
| 147 | class Cleanup { |
| 148 | // Anchor the construction vtable. |
| 149 | virtual void anchor(); |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 150 | |
| 151 | protected: |
| 152 | ~Cleanup() = default; |
| 153 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 154 | public: |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 155 | Cleanup(const Cleanup &) = default; |
| 156 | Cleanup(Cleanup &&) {} |
| 157 | Cleanup() = default; |
| 158 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 159 | /// Generation flags. |
| 160 | class Flags { |
| 161 | enum { |
| 162 | F_IsForEH = 0x1, |
| 163 | F_IsNormalCleanupKind = 0x2, |
| 164 | F_IsEHCleanupKind = 0x4 |
| 165 | }; |
| 166 | unsigned flags; |
| 167 | |
| 168 | public: |
| 169 | Flags() : flags(0) {} |
| 170 | |
| 171 | /// isForEH - true if the current emission is for an EH cleanup. |
| 172 | bool isForEHCleanup() const { return flags & F_IsForEH; } |
| 173 | bool isForNormalCleanup() const { return !isForEHCleanup(); } |
| 174 | void setIsForEHCleanup() { flags |= F_IsForEH; } |
| 175 | |
| 176 | bool isNormalCleanupKind() const { return flags & F_IsNormalCleanupKind; } |
| 177 | void setIsNormalCleanupKind() { flags |= F_IsNormalCleanupKind; } |
| 178 | |
| 179 | /// isEHCleanupKind - true if the cleanup was pushed as an EH |
| 180 | /// cleanup. |
| 181 | bool isEHCleanupKind() const { return flags & F_IsEHCleanupKind; } |
| 182 | void setIsEHCleanupKind() { flags |= F_IsEHCleanupKind; } |
| 183 | }; |
| 184 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 185 | |
| 186 | /// Emit the cleanup. For normal cleanups, this is run in the |
| 187 | /// same EH context as when the cleanup was pushed, i.e. the |
| 188 | /// immediately-enclosing context of the cleanup scope. For |
| 189 | /// EH cleanups, this is run in a terminate context. |
| 190 | /// |
| 191 | // \param flags cleanup kind. |
| 192 | virtual void Emit(CodeGenFunction &CGF, Flags flags) = 0; |
| 193 | }; |
| 194 | |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 195 | /// ConditionalCleanup stores the saved form of its parameters, |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 196 | /// then restores them and performs the cleanup. |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 197 | template <class T, class... As> |
| 198 | class ConditionalCleanup final : public Cleanup { |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 199 | typedef std::tuple<typename DominatingValue<As>::saved_type...> SavedTuple; |
| 200 | SavedTuple Saved; |
| 201 | |
| 202 | template <std::size_t... Is> |
| 203 | T restore(CodeGenFunction &CGF, llvm::index_sequence<Is...>) { |
| 204 | // It's important that the restores are emitted in order. The braced init |
| 205 | // list guarentees that. |
| 206 | return T{DominatingValue<As>::restore(CGF, std::get<Is>(Saved))...}; |
| 207 | } |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 208 | |
Stephen Hines | 651f13c | 2014-04-23 16:59:28 -0700 | [diff] [blame] | 209 | void Emit(CodeGenFunction &CGF, Flags flags) override { |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 210 | restore(CGF, llvm::index_sequence_for<As...>()).Emit(CGF, flags); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 211 | } |
| 212 | |
| 213 | public: |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 214 | ConditionalCleanup(typename DominatingValue<As>::saved_type... A) |
| 215 | : Saved(A...) {} |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 216 | |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 217 | ConditionalCleanup(SavedTuple Tuple) : Saved(std::move(Tuple)) {} |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 218 | }; |
| 219 | |
| 220 | private: |
| 221 | // The implementation for this class is in CGException.h and |
| 222 | // CGException.cpp; the definition is here because it's used as a |
| 223 | // member of CodeGenFunction. |
| 224 | |
| 225 | /// The start of the scope-stack buffer, i.e. the allocated pointer |
| 226 | /// for the buffer. All of these pointers are either simultaneously |
| 227 | /// null or simultaneously valid. |
| 228 | char *StartOfBuffer; |
| 229 | |
| 230 | /// The end of the buffer. |
| 231 | char *EndOfBuffer; |
| 232 | |
| 233 | /// The first valid entry in the buffer. |
| 234 | char *StartOfData; |
| 235 | |
| 236 | /// The innermost normal cleanup on the stack. |
| 237 | stable_iterator InnermostNormalCleanup; |
| 238 | |
| 239 | /// The innermost EH scope on the stack. |
| 240 | stable_iterator InnermostEHScope; |
| 241 | |
| 242 | /// The current set of branch fixups. A branch fixup is a jump to |
| 243 | /// an as-yet unemitted label, i.e. a label for which we don't yet |
| 244 | /// know the EH stack depth. Whenever we pop a cleanup, we have |
| 245 | /// to thread all the current branch fixups through it. |
| 246 | /// |
| 247 | /// Fixups are recorded as the Use of the respective branch or |
| 248 | /// switch statement. The use points to the final destination. |
| 249 | /// When popping out of a cleanup, these uses are threaded through |
| 250 | /// the cleanup and adjusted to point to the new cleanup. |
| 251 | /// |
| 252 | /// Note that branches are allowed to jump into protected scopes |
| 253 | /// in certain situations; e.g. the following code is legal: |
| 254 | /// struct A { ~A(); }; // trivial ctor, non-trivial dtor |
| 255 | /// goto foo; |
| 256 | /// A a; |
| 257 | /// foo: |
| 258 | /// bar(); |
| 259 | SmallVector<BranchFixup, 8> BranchFixups; |
| 260 | |
| 261 | char *allocate(size_t Size); |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 262 | void deallocate(size_t Size); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 263 | |
| 264 | void *pushCleanup(CleanupKind K, size_t DataSize); |
| 265 | |
| 266 | public: |
Stephen Hines | 6bcf27b | 2014-05-29 04:14:42 -0700 | [diff] [blame] | 267 | EHScopeStack() : StartOfBuffer(nullptr), EndOfBuffer(nullptr), |
| 268 | StartOfData(nullptr), InnermostNormalCleanup(stable_end()), |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 269 | InnermostEHScope(stable_end()) {} |
| 270 | ~EHScopeStack() { delete[] StartOfBuffer; } |
| 271 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 272 | /// Push a lazily-created cleanup on the stack. |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 273 | template <class T, class... As> void pushCleanup(CleanupKind Kind, As... A) { |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 274 | static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment, |
| 275 | "Cleanup's alignment is too large."); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 276 | void *Buffer = pushCleanup(Kind, sizeof(T)); |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 277 | Cleanup *Obj = new (Buffer) T(A...); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 278 | (void) Obj; |
| 279 | } |
| 280 | |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 281 | /// Push a lazily-created cleanup on the stack. Tuple version. |
| 282 | template <class T, class... As> |
| 283 | void pushCleanupTuple(CleanupKind Kind, std::tuple<As...> A) { |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 284 | static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment, |
| 285 | "Cleanup's alignment is too large."); |
Pirama Arumuga Nainar | 3ea9e33 | 2015-04-08 08:57:32 -0700 | [diff] [blame] | 286 | void *Buffer = pushCleanup(Kind, sizeof(T)); |
| 287 | Cleanup *Obj = new (Buffer) T(std::move(A)); |
| 288 | (void) Obj; |
| 289 | } |
| 290 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 291 | // Feel free to add more variants of the following: |
| 292 | |
| 293 | /// Push a cleanup with non-constant storage requirements on the |
| 294 | /// stack. The cleanup type must provide an additional static method: |
| 295 | /// static size_t getExtraSize(size_t); |
| 296 | /// The argument to this method will be the value N, which will also |
| 297 | /// be passed as the first argument to the constructor. |
| 298 | /// |
| 299 | /// The data stored in the extra storage must obey the same |
| 300 | /// restrictions as normal cleanup member data. |
| 301 | /// |
| 302 | /// The pointer returned from this method is valid until the cleanup |
| 303 | /// stack is modified. |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 304 | template <class T, class... As> |
| 305 | T *pushCleanupWithExtra(CleanupKind Kind, size_t N, As... A) { |
Pirama Arumuga Nainar | 87d948e | 2016-03-03 15:49:35 -0800 | [diff] [blame] | 306 | static_assert(llvm::AlignOf<T>::Alignment <= ScopeStackAlignment, |
| 307 | "Cleanup's alignment is too large."); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 308 | void *Buffer = pushCleanup(Kind, sizeof(T) + T::getExtraSize(N)); |
Stephen Hines | 0e2c34f | 2015-03-23 12:09:02 -0700 | [diff] [blame] | 309 | return new (Buffer) T(N, A...); |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 310 | } |
| 311 | |
| 312 | void pushCopyOfCleanup(CleanupKind Kind, const void *Cleanup, size_t Size) { |
| 313 | void *Buffer = pushCleanup(Kind, Size); |
| 314 | std::memcpy(Buffer, Cleanup, Size); |
| 315 | } |
| 316 | |
| 317 | /// Pops a cleanup scope off the stack. This is private to CGCleanup.cpp. |
| 318 | void popCleanup(); |
| 319 | |
| 320 | /// Push a set of catch handlers on the stack. The catch is |
| 321 | /// uninitialized and will need to have the given number of handlers |
| 322 | /// set on it. |
| 323 | class EHCatchScope *pushCatch(unsigned NumHandlers); |
| 324 | |
| 325 | /// Pops a catch scope off the stack. This is private to CGException.cpp. |
| 326 | void popCatch(); |
| 327 | |
| 328 | /// Push an exceptions filter on the stack. |
| 329 | class EHFilterScope *pushFilter(unsigned NumFilters); |
| 330 | |
| 331 | /// Pops an exceptions filter off the stack. |
| 332 | void popFilter(); |
| 333 | |
| 334 | /// Push a terminate handler on the stack. |
| 335 | void pushTerminate(); |
| 336 | |
| 337 | /// Pops a terminate handler off the stack. |
| 338 | void popTerminate(); |
| 339 | |
Pirama Arumuga Nainar | b6d6993 | 2015-07-01 12:25:36 -0700 | [diff] [blame] | 340 | // Returns true iff the current scope is either empty or contains only |
| 341 | // lifetime markers, i.e. no real cleanup code |
| 342 | bool containsOnlyLifetimeMarkers(stable_iterator Old) const; |
| 343 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 344 | /// Determines whether the exception-scopes stack is empty. |
| 345 | bool empty() const { return StartOfData == EndOfBuffer; } |
| 346 | |
Pirama Arumuga Nainar | 4967a71 | 2016-09-19 22:19:55 -0700 | [diff] [blame^] | 347 | bool requiresLandingPad() const; |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 348 | |
| 349 | /// Determines whether there are any normal cleanups on the stack. |
| 350 | bool hasNormalCleanups() const { |
| 351 | return InnermostNormalCleanup != stable_end(); |
| 352 | } |
| 353 | |
| 354 | /// Returns the innermost normal cleanup on the stack, or |
| 355 | /// stable_end() if there are no normal cleanups. |
| 356 | stable_iterator getInnermostNormalCleanup() const { |
| 357 | return InnermostNormalCleanup; |
| 358 | } |
| 359 | stable_iterator getInnermostActiveNormalCleanup() const; |
| 360 | |
| 361 | stable_iterator getInnermostEHScope() const { |
| 362 | return InnermostEHScope; |
| 363 | } |
| 364 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 365 | |
| 366 | /// An unstable reference to a scope-stack depth. Invalidated by |
| 367 | /// pushes but not pops. |
| 368 | class iterator; |
| 369 | |
| 370 | /// Returns an iterator pointing to the innermost EH scope. |
| 371 | iterator begin() const; |
| 372 | |
| 373 | /// Returns an iterator pointing to the outermost EH scope. |
| 374 | iterator end() const; |
| 375 | |
| 376 | /// Create a stable reference to the top of the EH stack. The |
| 377 | /// returned reference is valid until that scope is popped off the |
| 378 | /// stack. |
| 379 | stable_iterator stable_begin() const { |
| 380 | return stable_iterator(EndOfBuffer - StartOfData); |
| 381 | } |
| 382 | |
| 383 | /// Create a stable reference to the bottom of the EH stack. |
| 384 | static stable_iterator stable_end() { |
| 385 | return stable_iterator(0); |
| 386 | } |
| 387 | |
| 388 | /// Translates an iterator into a stable_iterator. |
| 389 | stable_iterator stabilize(iterator it) const; |
| 390 | |
| 391 | /// Turn a stable reference to a scope depth into a unstable pointer |
| 392 | /// to the EH stack. |
| 393 | iterator find(stable_iterator save) const; |
| 394 | |
Reid Kleckner | 43a75fc | 2013-06-19 17:07:50 +0000 | [diff] [blame] | 395 | /// Add a branch fixup to the current cleanup scope. |
| 396 | BranchFixup &addBranchFixup() { |
| 397 | assert(hasNormalCleanups() && "adding fixup in scope without cleanups"); |
| 398 | BranchFixups.push_back(BranchFixup()); |
| 399 | return BranchFixups.back(); |
| 400 | } |
| 401 | |
| 402 | unsigned getNumBranchFixups() const { return BranchFixups.size(); } |
| 403 | BranchFixup &getBranchFixup(unsigned I) { |
| 404 | assert(I < getNumBranchFixups()); |
| 405 | return BranchFixups[I]; |
| 406 | } |
| 407 | |
| 408 | /// Pops lazily-removed fixups from the end of the list. This |
| 409 | /// should only be called by procedures which have just popped a |
| 410 | /// cleanup or resolved one or more fixups. |
| 411 | void popNullFixups(); |
| 412 | |
| 413 | /// Clears the branch-fixups list. This should only be called by |
| 414 | /// ResolveAllBranchFixups. |
| 415 | void clearFixups() { BranchFixups.clear(); } |
| 416 | }; |
| 417 | |
| 418 | } // namespace CodeGen |
| 419 | } // namespace clang |
| 420 | |
| 421 | #endif |