CGCleanup.cpp File Reference

#include "CGCleanup.h"
#include "CodeGenFunction.h"

Include dependency graph for CGCleanup.cpp:

Go to the source code of this file.

Enumerations
enum	ForActivation_t { ForActivation, ForDeactivation }
Functions
static void	ResolveAllBranchFixups (CodeGenFunction &CGF, llvm::SwitchInst *Switch, llvm::BasicBlock *CleanupEntry)
static llvm::SwitchInst *	TransitionToCleanupSwitch (CodeGenFunction &CGF, llvm::BasicBlock *Block)
static llvm::BasicBlock *	CreateNormalEntry (CodeGenFunction &CGF, EHCleanupScope &Scope)
static llvm::BasicBlock *	SimplifyCleanupEntry (CodeGenFunction &CGF, llvm::BasicBlock *Entry)
	Attempts to reduce a cleanup's entry block to a fallthrough. This is basically llvm::MergeBlockIntoPredecessor, except simplified/optimized for the tighter constraints on cleanup blocks.
static void	EmitCleanup (CodeGenFunction &CGF, EHScopeStack::Cleanup *Fn, EHScopeStack::Cleanup::Flags flags, llvm::Value *ActiveFlag)
static void	ForwardPrebranchedFallthrough (llvm::BasicBlock *Exit, llvm::BasicBlock *From, llvm::BasicBlock *To)
static void	destroyOptimisticNormalEntry (CodeGenFunction &CGF, EHCleanupScope &scope)
	We don't need a normal entry block for the given cleanup. Optimistic fixup branches can cause these blocks to come into existence anyway; if so, destroy it.
static bool	IsUsedAsNormalCleanup (EHScopeStack &EHStack, EHScopeStack::stable_iterator C)
static bool	IsUsedAsEHCleanup (EHScopeStack &EHStack, EHScopeStack::stable_iterator cleanup)
static void	SetupCleanupBlockActivation (CodeGenFunction &CGF, EHScopeStack::stable_iterator C, ForActivation_t kind, llvm::Instruction *dominatingIP)
	The given cleanup block is changing activation state. Configure a cleanup variable if necessary.

---

Enumeration Type Documentation

enum ForActivation_t

Enumerator:

ForActivation
ForDeactivation

Definition at line 1032 of file CGCleanup.cpp.

---

Function Documentation

static llvm::BasicBlock* CreateNormalEntry	(	CodeGenFunction &	CGF,
		EHCleanupScope &	Scope
	)		[static]

Definition at line 417 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::createBasicBlock(), clang::CodeGen::EHCleanupScope::getNormalBlock(), clang::CodeGen::EHCleanupScope::isNormalCleanup(), and clang::CodeGen::EHCleanupScope::setNormalBlock().

Referenced by clang::CodeGen::CodeGenFunction::EmitBranchThroughCleanup(), and clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static void destroyOptimisticNormalEntry	(	CodeGenFunction &	CGF,
		EHCleanupScope &	scope
	)		[static]

We don't need a normal entry block for the given cleanup. Optimistic fixup branches can cause these blocks to come into existence anyway; if so, destroy it.

The validity of this transformation is very much specific to the exact ways in which we form branches to cleanup entries.

Definition at line 522 of file CGCleanup.cpp.

References clang::CodeGen::EHCleanupScope::getNormalBlock(), clang::CodeGen::CodeGenFunction::getUnreachableBlock(), and clang::CodeGen::CodeGenFunction::NormalCleanupDest.

Referenced by clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static void EmitCleanup	(	CodeGenFunction &	CGF,
		EHScopeStack::Cleanup *	Fn,
		EHScopeStack::Cleanup::Flags	flags,
		llvm::Value *	ActiveFlag
	)		[static]

Definition at line 467 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::Builder, clang::CodeGen::CodeGenFunction::createBasicBlock(), clang::CodeGen::CodeGenFunction::EHStack, clang::CodeGen::EHScopeStack::Cleanup::Emit(), clang::CodeGen::CodeGenFunction::EmitBlock(), clang::CodeGen::CodeGenFunction::HaveInsertPoint(), clang::CodeGen::EHScopeStack::Cleanup::Flags::isForEHCleanup(), clang::CodeGen::EHScopeStack::popTerminate(), and clang::CodeGen::EHScopeStack::pushTerminate().

Referenced by clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static void ForwardPrebranchedFallthrough	(	llvm::BasicBlock *	Exit,
		llvm::BasicBlock *	From,
		llvm::BasicBlock *	To
	)		[static]

Definition at line 498 of file CGCleanup.cpp.

Referenced by clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static bool IsUsedAsEHCleanup	(	EHScopeStack &	EHStack,
		EHScopeStack::stable_iterator	cleanup
	)		[static]

Definition at line 1011 of file CGCleanup.cpp.

References clang::CodeGen::EHScopeStack::find(), clang::CodeGen::EHScopeStack::getInnermostEHScope(), clang::CodeGen::EHScope::hasEHBranches(), and clang::CodeGen::EHScopeStack::stable_iterator::strictlyEncloses().

Referenced by SetupCleanupBlockActivation().

static bool IsUsedAsNormalCleanup	(	EHScopeStack &	EHStack,
		EHScopeStack::stable_iterator	C
	)		[static]

Definition at line 992 of file CGCleanup.cpp.

References AttributeLangSupport::C, clang::CodeGen::EHScopeStack::find(), clang::CodeGen::EHScopeStack::getInnermostNormalCleanup(), S, and clang::CodeGen::EHScopeStack::stable_iterator::strictlyEncloses().

Referenced by SetupCleanupBlockActivation().

static void ResolveAllBranchFixups	(	CodeGenFunction &	CGF,
		llvm::SwitchInst *	Switch,
		llvm::BasicBlock *	CleanupEntry
	)		[static]

All the branch fixups on the EH stack have propagated out past the outermost normal cleanup; resolve them all by adding cases to the given switch instruction.

Definition at line 278 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::Builder, clang::CodeGen::EHScopeStack::clearFixups(), clang::CodeGen::BranchFixup::Destination, clang::CodeGen::BranchFixup::DestinationIndex, clang::CodeGen::CodeGenFunction::EHStack, clang::CodeGen::EHScopeStack::getBranchFixup(), clang::CodeGen::CodeGenFunction::getNormalCleanupDestSlot(), clang::CodeGen::EHScopeStack::getNumBranchFixups(), clang::CodeGen::BranchFixup::InitialBranch, and clang::CodeGen::BranchFixup::OptimisticBranchBlock.

Referenced by clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static void SetupCleanupBlockActivation	(	CodeGenFunction &	CGF,
		EHScopeStack::stable_iterator	C,
		ForActivation_t	kind,
		llvm::Instruction *	dominatingIP
	)		[static]

The given cleanup block is changing activation state. Configure a cleanup variable if necessary.

It would be good if we had some way of determining if there were extra uses *after* the change-over point.

Definition at line 1042 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::Builder, clang::CodeGen::CodeGenFunction::CreateTempAlloca(), clang::CodeGen::CodeGenFunction::EHStack, clang::CodeGen::EHScopeStack::find(), ForActivation, ForDeactivation, clang::CodeGen::EHCleanupScope::getActiveFlag(), clang::CodeGen::EHCleanupScope::isEHCleanup(), clang::CodeGen::CodeGenFunction::isInConditionalBranch(), clang::CodeGen::EHCleanupScope::isNormalCleanup(), IsUsedAsEHCleanup(), IsUsedAsNormalCleanup(), clang::CodeGen::EHCleanupScope::setActiveFlag(), clang::CodeGen::CodeGenFunction::setBeforeOutermostConditional(), clang::CodeGen::EHCleanupScope::setTestFlagInEHCleanup(), and clang::CodeGen::EHCleanupScope::setTestFlagInNormalCleanup().

Referenced by clang::CodeGen::CodeGenFunction::ActivateCleanupBlock(), and clang::CodeGen::CodeGenFunction::DeactivateCleanupBlock().

static llvm::BasicBlock* SimplifyCleanupEntry	(	CodeGenFunction &	CGF,
		llvm::BasicBlock *	Entry
	)		[static]

Attempts to reduce a cleanup's entry block to a fallthrough. This is basically llvm::MergeBlockIntoPredecessor, except simplified/optimized for the tighter constraints on cleanup blocks.

Returns the new block, whatever it is.

Definition at line 433 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::Builder.

Referenced by clang::CodeGen::CodeGenFunction::PopCleanupBlock().

static llvm::SwitchInst* TransitionToCleanupSwitch	(	CodeGenFunction &	CGF,
		llvm::BasicBlock *	Block
	)		[static]

Transitions the terminator of the given exit-block of a cleanup to be a cleanup switch.

Definition at line 315 of file CGCleanup.cpp.

References clang::CodeGen::CodeGenFunction::getNormalCleanupDestSlot().

Referenced by clang::CodeGen::CodeGenFunction::ResolveBranchFixups().