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Make class comment visible in Doxygen.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28436 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Vladimir Prus
2006-05-23 15:32:15 +00:00
parent 124729155d
commit 1fd8a4f65d
1 changed files with 31 additions and 28 deletions
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59
include/llvm/CodeGen/MachineFrameInfo.h
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@@ -6,34 +6,7 @@
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The MachineFrameInfo class represents an abstract stack frame until
// prolog/epilog code is inserted. This class is key to allowing stack frame
// representation optimizations, such as frame pointer elimination. It also
// allows more mundane (but still important) optimizations, such as reordering
// of abstract objects on the stack frame.
//
// To support this, the class assigns unique integer identifiers to stack
// objects requested clients. These identifiers are negative integers for fixed
// stack objects (such as arguments passed on the stack) or positive for objects
// that may be reordered. Instructions which refer to stack objects use a
// special MO_FrameIndex operand to represent these frame indexes.
//
// Because this class keeps track of all references to the stack frame, it knows
// when a variable sized object is allocated on the stack. This is the sole
// condition which prevents frame pointer elimination, which is an important
// optimization on register-poor architectures. Because original variable sized
// alloca's in the source program are the only source of variable sized stack
// objects, it is safe to decide whether there will be any variable sized
// objects before all stack objects are known (for example, register allocator
// spill code never needs variable sized objects).
//
// When prolog/epilog code emission is performed, the final stack frame is built
// and the machine instructions are modified to refer to the actual stack
// offsets of the object, eliminating all MO_FrameIndex operands from the
// program.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H
#define LLVM_CODEGEN_MACHINEFRAMEINFO_H
@@ -47,6 +20,36 @@ class Type;
class MachineDebugInfo;
class MachineFunction;
/// The MachineFrameInfo class represents an abstract stack frame until
/// prolog/epilog code is inserted. This class is key to allowing stack frame
/// representation optimizations, such as frame pointer elimination. It also
/// allows more mundane (but still important) optimizations, such as reordering
/// of abstract objects on the stack frame.
///
/// To support this, the class assigns unique integer identifiers to stack
/// objects requested clients. These identifiers are negative integers for
/// fixed stack objects (such as arguments passed on the stack) or positive
/// for objects that may be reordered. Instructions which refer to stack
/// objects use a special MO_FrameIndex operand to represent these frame
/// indexes.
///
/// Because this class keeps track of all references to the stack frame, it
/// knows when a variable sized object is allocated on the stack. This is the
/// sole condition which prevents frame pointer elimination, which is an
/// important optimization on register-poor architectures. Because original
/// variable sized alloca's in the source program are the only source of
/// variable sized stack objects, it is safe to decide whether there will be
/// any variable sized objects before all stack objects are known (for
/// example, register allocator spill code never needs variable sized
/// objects).
///
/// When prolog/epilog code emission is performed, the final stack frame is
/// built and the machine instructions are modified to refer to the actual
/// stack offsets of the object, eliminating all MO_FrameIndex operands from
/// the program.
///
/// @brief Abstract Stack Frame Information
class MachineFrameInfo {
// StackObject - Represent a single object allocated on the stack.