diff options
Diffstat (limited to 'include/llvm/IR/User.h')
| -rw-r--r-- | include/llvm/IR/User.h | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/include/llvm/IR/User.h b/include/llvm/IR/User.h index 4dfa19cf241f..d6a603ce845d 100644 --- a/include/llvm/IR/User.h +++ b/include/llvm/IR/User.h @@ -36,7 +36,7 @@ namespace llvm { template <typename T> class ArrayRef; template <typename T> class MutableArrayRef; -/// \brief Compile-time customization of User operands. +/// Compile-time customization of User operands. /// /// Customizes operand-related allocators and accessors. template <class> @@ -81,13 +81,13 @@ protected: "Error in initializing hung off uses for User"); } - /// \brief Allocate the array of Uses, followed by a pointer + /// Allocate the array of Uses, followed by a pointer /// (with bottom bit set) to the User. /// \param IsPhi identifies callers which are phi nodes and which need /// N BasicBlock* allocated along with N void allocHungoffUses(unsigned N, bool IsPhi = false); - /// \brief Grow the number of hung off uses. Note that allocHungoffUses + /// Grow the number of hung off uses. Note that allocHungoffUses /// should be called if there are no uses. void growHungoffUses(unsigned N, bool IsPhi = false); @@ -97,15 +97,31 @@ protected: public: User(const User &) = delete; - /// \brief Free memory allocated for User and Use objects. + /// Free memory allocated for User and Use objects. void operator delete(void *Usr); - /// \brief Placement delete - required by std, but never called. - void operator delete(void*, unsigned) { + /// Placement delete - required by std, called if the ctor throws. + void operator delete(void *Usr, unsigned) { + // Note: If a subclass manipulates the information which is required to calculate the + // Usr memory pointer, e.g. NumUserOperands, the operator delete of that subclass has + // to restore the changed information to the original value, since the dtor of that class + // is not called if the ctor fails. + User::operator delete(Usr); + +#ifndef LLVM_ENABLE_EXCEPTIONS llvm_unreachable("Constructor throws?"); +#endif } - /// \brief Placement delete - required by std, but never called. - void operator delete(void*, unsigned, bool) { + /// Placement delete - required by std, called if the ctor throws. + void operator delete(void *Usr, unsigned, bool) { + // Note: If a subclass manipulates the information which is required to calculate the + // Usr memory pointer, e.g. NumUserOperands, the operator delete of that subclass has + // to restore the changed information to the original value, since the dtor of that class + // is not called if the ctor fails. + User::operator delete(Usr); + +#ifndef LLVM_ENABLE_EXCEPTIONS llvm_unreachable("Constructor throws?"); +#endif } protected: @@ -194,7 +210,7 @@ public: NumUserOperands = NumOps; } - /// \brief Subclasses with hung off uses need to manage the operand count + /// Subclasses with hung off uses need to manage the operand count /// themselves. In these instances, the operand count isn't used to find the /// OperandList, so there's no issue in having the operand count change. void setNumHungOffUseOperands(unsigned NumOps) { @@ -226,7 +242,7 @@ public: return const_op_range(op_begin(), op_end()); } - /// \brief Iterator for directly iterating over the operand Values. + /// Iterator for directly iterating over the operand Values. struct value_op_iterator : iterator_adaptor_base<value_op_iterator, op_iterator, std::random_access_iterator_tag, Value *, @@ -268,7 +284,7 @@ public: return make_range(value_op_begin(), value_op_end()); } - /// \brief Drop all references to operands. + /// Drop all references to operands. /// /// This function is in charge of "letting go" of all objects that this User /// refers to. This allows one to 'delete' a whole class at a time, even @@ -281,7 +297,7 @@ public: U.set(nullptr); } - /// \brief Replace uses of one Value with another. + /// Replace uses of one Value with another. /// /// Replaces all references to the "From" definition with references to the /// "To" definition. |