WebAssemblyCFGSort.cpp File Reference

This file implements a CFG sorting pass. More...

#include "WebAssembly.h"
#include "WebAssemblyExceptionInfo.h"
#include "WebAssemblySortRegion.h"
#include "WebAssemblyUtilities.h"
#include "llvm/ADT/PriorityQueue.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/WasmEHFuncInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "wasm-cfg-sort"

Functions
	INITIALIZE_PASS (WebAssemblyCFGSort, DEBUG_TYPE, "Reorders blocks in topological order", false, false) FunctionPass *llvm
static void	maybeUpdateTerminator (MachineBasicBlock *MBB)
static void	sortBlocks (MachineFunction &MF, const MachineLoopInfo &MLI, const WebAssemblyExceptionInfo &WEI, MachineDominatorTree &MDT)
	Sort the blocks, taking special care to make sure that regions are not interrupted by blocks not dominated by their header.

Variables
static cl::opt< bool >	WasmDisableEHPadSort ("wasm-disable-ehpad-sort", cl::ReallyHidden, cl::desc("WebAssembly: Disable EH pad-first sort order. Testing purpose only."), cl::init(false))

Detailed Description

This file implements a CFG sorting pass.

This pass reorders the blocks in a function to put them into topological order, ignoring loop backedges, and without any loop or exception being interrupted by a block not dominated by the its header, with special care to keep the order as similar as possible to the original order.

Definition in file WebAssemblyCFGSort.cpp.

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "wasm-cfg-sort"

Definition at line 37 of file WebAssemblyCFGSort.cpp.

Function Documentation

INITIALIZE_PASS()

INITIALIZE_PASS	(	WebAssemblyCFGSort	,
		DEBUG_TYPE	,
		"Reorders blocks in topological order"	,
		false	,
		false
	)

Definition at line 72 of file WebAssemblyCFGSort.cpp.

maybeUpdateTerminator()

static void maybeUpdateTerminator ( MachineBasicBlock *  MBB )

static

Definition at line 79 of file WebAssemblyCFGSort.cpp.

References assert(), llvm::MachineFunction::getBlockNumbered(), llvm::MachineBasicBlock::getNumber(), llvm::MachineFunction::getNumBlockIDs(), llvm::MachineBasicBlock::getParent(), MBB, llvm::MachineBasicBlock::terminators(), and llvm::MachineBasicBlock::updateTerminator().

Referenced by sortBlocks().

sortBlocks()

static void sortBlocks ( MachineFunction &  MF, const MachineLoopInfo &  MLI, const WebAssemblyExceptionInfo &  WEI, MachineDominatorTree &  MDT  )

static

Sort the blocks, taking special care to make sure that regions are not interrupted by blocks not dominated by their header.

TODO: There are many opportunities for improving the heuristics here. Explore them.

Definition at line 185 of file WebAssemblyCFGSort.cpp.

References assert(), llvm::SetVector< T, Vector, Set, N >::back(), llvm::RegionBase< Tr >::contains(), llvm::SetVector< T, Vector, Set, N >::count(), llvm::SmallPtrSetImpl< PtrType >::count(), llvm::MachineDominatorTree::dominates(), llvm::SetVector< T, Vector, Set, N >::empty(), llvm::MachineFunction::front(), llvm::WebAssembly::SortRegionInfo::getBottom(), llvm::LoopInfoBase< BlockT, LoopT >::getLoopFor(), llvm::MachineBasicBlock::getNumber(), llvm::MachineFunction::getNumBlockIDs(), llvm::WebAssembly::SortRegionInfo::getRegionFor(), llvm::MachineFunction::getWasmEHFuncInfo(), llvm::SetVector< T, Vector, Set, N >::insert(), llvm::MachineBasicBlock::isEHPad(), maybeUpdateTerminator(), MBB, llvm::MachineBasicBlock::moveAfter(), N, llvm::SetVector< T, Vector, Set, N >::pop_back(), llvm::SetVector< T, Vector, Set, N >::pop_back_val(), llvm::MachineBasicBlock::pred_size(), llvm::MachineBasicBlock::predecessors(), llvm::MachineFunction::RenumberBlocks(), llvm::SetVector< T, Vector, Set, N >::size(), llvm::MachineBasicBlock::successors(), llvm::DominatorTreeBase< NodeT, IsPostDom >::updateBlockNumbers(), and WasmDisableEHPadSort.

Variable Documentation

WasmDisableEHPadSort

cl::opt< bool > WasmDisableEHPadSort("wasm-disable-ehpad-sort", cl::ReallyHidden, cl::desc( "WebAssembly: Disable EH pad-first sort order. Testing purpose only."), cl::init(false)) ( "wasm-disable-ehpad-sort"  , cl::ReallyHidden  , cl::desc( "WebAssembly: Disable EH pad-first sort order. Testing purpose only.")  , cl::init(false)    )

static

Referenced by sortBlocks().