mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-19 19:29:31 +00:00
* Enable SCCP debugging to be turned on with a simple change of #define
* Change worklist to a set so that duplicates cannot happen * Add support for the invoke instruction * Avoid marking store and free instructions as overdefined, since they cannot produce a value anyway. * Inline the OperandChangedState implementation * Add isEdgeFeasible in preparation to fix a bug. Right now it behaves exactly as before. * Remove obsolete comment about constant pools git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2445 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
a1ab959de3
commit
59f0ce2a41
@ -30,6 +30,12 @@
|
|||||||
#include <iostream>
|
#include <iostream>
|
||||||
using std::cerr;
|
using std::cerr;
|
||||||
|
|
||||||
|
#if 0 // Enable this to get SCCP debug output
|
||||||
|
#define DEBUG_SCCP(X) X
|
||||||
|
#else
|
||||||
|
#define DEBUG_SCCP(X)
|
||||||
|
#endif
|
||||||
|
|
||||||
// InstVal class - This class represents the different lattice values that an
|
// InstVal class - This class represents the different lattice values that an
|
||||||
// instruction may occupy. It is a simple class with value semantics.
|
// instruction may occupy. It is a simple class with value semantics.
|
||||||
//
|
//
|
||||||
@ -86,7 +92,7 @@ class SCCP : public FunctionPass, public InstVisitor<SCCP> {
|
|||||||
std::set<BasicBlock*> BBExecutable;// The basic blocks that are executable
|
std::set<BasicBlock*> BBExecutable;// The basic blocks that are executable
|
||||||
std::map<Value*, InstVal> ValueState; // The state each value is in...
|
std::map<Value*, InstVal> ValueState; // The state each value is in...
|
||||||
|
|
||||||
std::vector<Instruction*> InstWorkList;// The instruction work list
|
std::set<Instruction*> InstWorkList;// The instruction work list
|
||||||
std::vector<BasicBlock*> BBWorkList; // The BasicBlock work list
|
std::vector<BasicBlock*> BBWorkList; // The BasicBlock work list
|
||||||
public:
|
public:
|
||||||
|
|
||||||
@ -116,9 +122,10 @@ private:
|
|||||||
// the users of the instruction are updated later.
|
// the users of the instruction are updated later.
|
||||||
//
|
//
|
||||||
inline bool markConstant(Instruction *I, Constant *V) {
|
inline bool markConstant(Instruction *I, Constant *V) {
|
||||||
//cerr << "markConstant: " << V << " = " << I;
|
DEBUG_SCCP(cerr << "markConstant: " << V << " = " << I);
|
||||||
|
|
||||||
if (ValueState[I].markConstant(V)) {
|
if (ValueState[I].markConstant(V)) {
|
||||||
InstWorkList.push_back(I);
|
InstWorkList.insert(I);
|
||||||
return true;
|
return true;
|
||||||
}
|
}
|
||||||
return false;
|
return false;
|
||||||
@ -131,8 +138,8 @@ private:
|
|||||||
inline bool markOverdefined(Value *V) {
|
inline bool markOverdefined(Value *V) {
|
||||||
if (ValueState[V].markOverdefined()) {
|
if (ValueState[V].markOverdefined()) {
|
||||||
if (Instruction *I = dyn_cast<Instruction>(V)) {
|
if (Instruction *I = dyn_cast<Instruction>(V)) {
|
||||||
//cerr << "markOverdefined: " << V;
|
DEBUG_SCCP(cerr << "markOverdefined: " << V);
|
||||||
InstWorkList.push_back(I); // Only instructions go on the work list
|
InstWorkList.insert(I); // Only instructions go on the work list
|
||||||
}
|
}
|
||||||
return true;
|
return true;
|
||||||
}
|
}
|
||||||
@ -163,7 +170,7 @@ private:
|
|||||||
//
|
//
|
||||||
void markExecutable(BasicBlock *BB) {
|
void markExecutable(BasicBlock *BB) {
|
||||||
if (BBExecutable.count(BB)) return;
|
if (BBExecutable.count(BB)) return;
|
||||||
//cerr << "Marking BB Executable: " << BB;
|
DEBUG_SCCP(cerr << "Marking BB Executable: " << BB);
|
||||||
BBExecutable.insert(BB); // Basic block is executable!
|
BBExecutable.insert(BB); // Basic block is executable!
|
||||||
BBWorkList.push_back(BB); // Add the block to the work list!
|
BBWorkList.push_back(BB); // Add the block to the work list!
|
||||||
}
|
}
|
||||||
@ -178,6 +185,7 @@ private:
|
|||||||
// Terminators
|
// Terminators
|
||||||
void visitReturnInst(ReturnInst *I) { /*does not have an effect*/ }
|
void visitReturnInst(ReturnInst *I) { /*does not have an effect*/ }
|
||||||
void visitBranchInst(BranchInst *I);
|
void visitBranchInst(BranchInst *I);
|
||||||
|
void visitInvokeInst(InvokeInst *I);
|
||||||
void visitSwitchInst(SwitchInst *I);
|
void visitSwitchInst(SwitchInst *I);
|
||||||
|
|
||||||
void visitUnaryOperator(Instruction *I);
|
void visitUnaryOperator(Instruction *I);
|
||||||
@ -186,11 +194,12 @@ private:
|
|||||||
void visitShiftInst(ShiftInst *I) { visitBinaryOperator(I); }
|
void visitShiftInst(ShiftInst *I) { visitBinaryOperator(I); }
|
||||||
|
|
||||||
// Instructions that cannot be folded away...
|
// Instructions that cannot be folded away...
|
||||||
|
void visitStoreInst (Instruction *I) { /*returns void*/ }
|
||||||
void visitMemAccessInst (Instruction *I) { markOverdefined(I); }
|
void visitMemAccessInst (Instruction *I) { markOverdefined(I); }
|
||||||
void visitCallInst (Instruction *I) { markOverdefined(I); }
|
void visitCallInst (Instruction *I) { markOverdefined(I); }
|
||||||
void visitInvokeInst (Instruction *I) { markOverdefined(I); }
|
void visitInvokeInst (Instruction *I) { markOverdefined(I); }
|
||||||
void visitAllocationInst(Instruction *I) { markOverdefined(I); }
|
void visitAllocationInst(Instruction *I) { markOverdefined(I); }
|
||||||
void visitFreeInst (Instruction *I) { markOverdefined(I); }
|
void visitFreeInst (Instruction *I) { /*returns void*/ }
|
||||||
|
|
||||||
void visitInstruction(Instruction *I) {
|
void visitInstruction(Instruction *I) {
|
||||||
// If a new instruction is added to LLVM that we don't handle...
|
// If a new instruction is added to LLVM that we don't handle...
|
||||||
@ -198,11 +207,21 @@ private:
|
|||||||
markOverdefined(I); // Just in case
|
markOverdefined(I); // Just in case
|
||||||
}
|
}
|
||||||
|
|
||||||
|
// isEdgeFeasible - Return true if the control flow edge from the 'From' basic
|
||||||
|
// block to the 'To' basic block is currently feasible...
|
||||||
|
//
|
||||||
|
bool isEdgeFeasible(BasicBlock *From, BasicBlock *To);
|
||||||
|
|
||||||
// OperandChangedState - This method is invoked on all of the users of an
|
// OperandChangedState - This method is invoked on all of the users of an
|
||||||
// instruction that was just changed state somehow.... Based on this
|
// instruction that was just changed state somehow.... Based on this
|
||||||
// information, we need to update the specified user of this instruction.
|
// information, we need to update the specified user of this instruction.
|
||||||
//
|
//
|
||||||
void OperandChangedState(User *U);
|
void OperandChangedState(User *U) {
|
||||||
|
// Only instructions use other variable values!
|
||||||
|
Instruction *I = cast<Instruction>(U);
|
||||||
|
if (!BBExecutable.count(I->getParent())) return;// Inst not executable yet!
|
||||||
|
visit(I);
|
||||||
|
}
|
||||||
};
|
};
|
||||||
} // end anonymous namespace
|
} // end anonymous namespace
|
||||||
|
|
||||||
@ -230,10 +249,10 @@ bool SCCP::runOnFunction(Function *F) {
|
|||||||
while (!BBWorkList.empty() || !InstWorkList.empty()) {
|
while (!BBWorkList.empty() || !InstWorkList.empty()) {
|
||||||
// Process the instruction work list...
|
// Process the instruction work list...
|
||||||
while (!InstWorkList.empty()) {
|
while (!InstWorkList.empty()) {
|
||||||
Instruction *I = InstWorkList.back();
|
Instruction *I = *InstWorkList.begin();
|
||||||
InstWorkList.pop_back();
|
InstWorkList.erase(InstWorkList.begin());
|
||||||
|
|
||||||
//cerr << "\nPopped off I-WL: " << I;
|
DEBUG_SCCP(cerr << "\nPopped off I-WL: " << I);
|
||||||
|
|
||||||
|
|
||||||
// "I" got into the work list because it either made the transition from
|
// "I" got into the work list because it either made the transition from
|
||||||
@ -250,7 +269,7 @@ bool SCCP::runOnFunction(Function *F) {
|
|||||||
BasicBlock *BB = BBWorkList.back();
|
BasicBlock *BB = BBWorkList.back();
|
||||||
BBWorkList.pop_back();
|
BBWorkList.pop_back();
|
||||||
|
|
||||||
//cerr << "\nPopped off BBWL: " << BB;
|
DEBUG_SCCP(cerr << "\nPopped off BBWL: " << BB);
|
||||||
|
|
||||||
// If this block only has a single successor, mark it as executable as
|
// If this block only has a single successor, mark it as executable as
|
||||||
// well... if not, terminate the do loop.
|
// well... if not, terminate the do loop.
|
||||||
@ -264,7 +283,7 @@ bool SCCP::runOnFunction(Function *F) {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
#if 0
|
#ifdef DEBUG_SCCP
|
||||||
for (Function::iterator BBI = F->begin(), BBEnd = F->end();
|
for (Function::iterator BBI = F->begin(), BBEnd = F->end();
|
||||||
BBI != BBEnd; ++BBI)
|
BBI != BBEnd; ++BBI)
|
||||||
if (!BBExecutable.count(*BBI))
|
if (!BBExecutable.count(*BBI))
|
||||||
@ -283,7 +302,7 @@ bool SCCP::runOnFunction(Function *F) {
|
|||||||
InstVal &IV = ValueState[Inst];
|
InstVal &IV = ValueState[Inst];
|
||||||
if (IV.isConstant()) {
|
if (IV.isConstant()) {
|
||||||
Constant *Const = IV.getConstant();
|
Constant *Const = IV.getConstant();
|
||||||
// cerr << "Constant: " << Inst << " is: " << Const;
|
DEBUG_SCCP(cerr << "Constant: " << Inst << " is: " << Const);
|
||||||
|
|
||||||
// Replaces all of the uses of a variable with uses of the constant.
|
// Replaces all of the uses of a variable with uses of the constant.
|
||||||
Inst->replaceAllUsesWith(Const);
|
Inst->replaceAllUsesWith(Const);
|
||||||
@ -305,17 +324,25 @@ bool SCCP::runOnFunction(Function *F) {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
// Reset state so that the next invokation will have empty data structures
|
// Reset state so that the next invocation will have empty data structures
|
||||||
BBExecutable.clear();
|
BBExecutable.clear();
|
||||||
ValueState.clear();
|
ValueState.clear();
|
||||||
|
|
||||||
// Merge identical constants last: this is important because we may have just
|
|
||||||
// introduced constants that already exist, and we don't want to pollute later
|
|
||||||
// stages with extraneous constants.
|
|
||||||
//
|
|
||||||
return MadeChanges;
|
return MadeChanges;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
// isEdgeFeasible - Return true if the control flow edge from the 'From' basic
|
||||||
|
// block to the 'To' basic block is currently feasible...
|
||||||
|
//
|
||||||
|
bool SCCP::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
|
||||||
|
assert(BBExecutable.count(To) && "Dest should always be alive!");
|
||||||
|
|
||||||
|
// Make sure the source basic block is executable!!
|
||||||
|
if (!BBExecutable.count(From)) return false;
|
||||||
|
|
||||||
|
// This should check the terminator in From!
|
||||||
|
return true;
|
||||||
|
}
|
||||||
|
|
||||||
// visit Implementations - Something changed in this instruction... Either an
|
// visit Implementations - Something changed in this instruction... Either an
|
||||||
// operand made a transition, or the instruction is newly executable. Change
|
// operand made a transition, or the instruction is newly executable. Change
|
||||||
@ -347,7 +374,7 @@ void SCCP::visitPHINode(PHINode *PN) {
|
|||||||
// If there are no executable operands, the PHI remains undefined.
|
// If there are no executable operands, the PHI remains undefined.
|
||||||
//
|
//
|
||||||
for (i = 0; i < NumValues; ++i) {
|
for (i = 0; i < NumValues; ++i) {
|
||||||
if (BBExecutable.count(PN->getIncomingBlock(i))) {
|
if (isEdgeFeasible(PN->getIncomingBlock(i), PN->getParent())) {
|
||||||
InstVal &IV = getValueState(PN->getIncomingValue(i));
|
InstVal &IV = getValueState(PN->getIncomingValue(i));
|
||||||
if (IV.isUndefined()) continue; // Doesn't influence PHI node.
|
if (IV.isUndefined()) continue; // Doesn't influence PHI node.
|
||||||
if (IV.isOverdefined()) { // PHI node becomes overdefined!
|
if (IV.isOverdefined()) { // PHI node becomes overdefined!
|
||||||
@ -403,6 +430,11 @@ void SCCP::visitBranchInst(BranchInst *BI) {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
void SCCP::visitInvokeInst(InvokeInst *II) {
|
||||||
|
markExecutable(II->getNormalDest());
|
||||||
|
markExecutable(II->getExceptionalDest());
|
||||||
|
}
|
||||||
|
|
||||||
void SCCP::visitSwitchInst(SwitchInst *SI) {
|
void SCCP::visitSwitchInst(SwitchInst *SI) {
|
||||||
InstVal &SCValue = getValueState(SI->getCondition());
|
InstVal &SCValue = getValueState(SI->getCondition());
|
||||||
if (SCValue.isOverdefined()) { // Overdefined condition? All dests are exe
|
if (SCValue.isOverdefined()) { // Overdefined condition? All dests are exe
|
||||||
@ -459,15 +491,3 @@ void SCCP::visitBinaryOperator(Instruction *I) {
|
|||||||
markOverdefined(I); // Don't know how to fold this instruction. :(
|
markOverdefined(I); // Don't know how to fold this instruction. :(
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
// OperandChangedState - This method is invoked on all of the users of an
|
|
||||||
// instruction that was just changed state somehow.... Based on this
|
|
||||||
// information, we need to update the specified user of this instruction.
|
|
||||||
//
|
|
||||||
void SCCP::OperandChangedState(User *U) {
|
|
||||||
// Only instructions use other variable values!
|
|
||||||
Instruction *I = cast<Instruction>(U);
|
|
||||||
if (!BBExecutable.count(I->getParent())) return; // Inst not executable yet!
|
|
||||||
|
|
||||||
visit(I);
|
|
||||||
}
|
|
||||||
|
Loading…
Reference in New Issue
Block a user