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Revert "Patch for function cloning to inline all blocks whose address is taken"

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as it was causing build failures in ruby.

This reverts commit r207713.

llvm-svn: 209135
This commit is contained in:
Eric Christopher 2014-05-19 16:04:10 +00:00
parent 46b39e0f70
commit 2c8f65cf87
1 changed files with 34 additions and 106 deletions
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140
lib/Transforms/Utils/CloneFunction.cpp
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@ -32,7 +32,6 @@
#include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ValueMapper.h" #include "llvm/Transforms/Utils/ValueMapper.h"
#include <map> #include <map>
#include <set>
using namespace llvm; using namespace llvm;
// CloneBasicBlock - See comments in Cloning.h // CloneBasicBlock - See comments in Cloning.h
@ -273,36 +272,42 @@ namespace {
NameSuffix(nameSuffix), CodeInfo(codeInfo), DL(DL) { NameSuffix(nameSuffix), CodeInfo(codeInfo), DL(DL) {
} }
/// CloneBlock - The specified block is found to be reachable, so clone it /// CloneBlock - The specified block is found to be reachable, clone it and
/// into NewBB. /// anything that it can reach.
/// ToClone is the vector of actually cloned blocks.
/// OrigBBs is the set of all blocks reacheable from the entry block.
/// It contains the block candidates and makes sure each block
/// is cloned at most once.
void CloneBlock(const BasicBlock *BB, void CloneBlock(const BasicBlock *BB,
BasicBlock *NewBB, std::vector<const BasicBlock*> &ToClone);
std::vector<const BasicBlock *> &ToClone,
std::set<const BasicBlock *> &OrigBBs);
}; };
} }
/// CloneBlock - The specified block is found to be reachable, so clone it /// CloneBlock - The specified block is found to be reachable, clone it and
/// into NewBB. /// anything that it can reach.
/// ToClone is the vector of actually cloned blocks.
/// OrigBBs is the set of all blocks reacheable from the entry block.
/// It contains the block candidates and makes sure each block
/// is cloned at most once.
void PruningFunctionCloner::CloneBlock(const BasicBlock *BB, void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
BasicBlock *NewBB, std::vector<const BasicBlock*> &ToClone){
std::vector<const BasicBlock *> &ToClone, WeakVH &BBEntry = VMap[BB];
std::set<const BasicBlock *> &OrigBBs) {
// Remove BB from list of blocks to clone.
// When it was not in the list, it has been cloned already, so
// don't clone again.
if (!OrigBBs.erase(BB)) return;
// Have we already cloned this block?
if (BBEntry) return;
// Nope, clone it now. // Nope, clone it now.
BasicBlock *NewBB;
BBEntry = NewBB = BasicBlock::Create(BB->getContext());
if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
// It is only legal to clone a function if a block address within that
// function is never referenced outside of the function. Given that, we
// want to map block addresses from the old function to block addresses in
// the clone. (This is different from the generic ValueMapper
// implementation, which generates an invalid blockaddress when
// cloning a function.)
//
// Note that we don't need to fix the mapping for unreachable blocks;
// the default mapping there is safe.
if (BB->hasAddressTaken()) {
Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
const_cast<BasicBlock*>(BB));
VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
}
bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false; bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
@ -420,7 +425,7 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
const DataLayout *DL, const DataLayout *DL,
Instruction *TheCall) { Instruction *TheCall) {
assert(NameSuffix && "NameSuffix cannot be null!"); assert(NameSuffix && "NameSuffix cannot be null!");
#ifndef NDEBUG #ifndef NDEBUG
for (Function::const_arg_iterator II = OldFunc->arg_begin(), for (Function::const_arg_iterator II = OldFunc->arg_begin(),
E = OldFunc->arg_end(); II != E; ++II) E = OldFunc->arg_end(); II != E; ++II)
@ -430,91 +435,15 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges, PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
NameSuffix, CodeInfo, DL); NameSuffix, CodeInfo, DL);
// Since all BB address references need to be known before block-by-block // Clone the entry block, and anything recursively reachable from it.
// processing, we need to create all reachable blocks before processing
// them for instruction cloning and pruning. Some of these blocks may
// be removed due to later pruning.
std::vector<const BasicBlock*> CloneWorklist; std::vector<const BasicBlock*> CloneWorklist;
//
// OrigBBs consists of all blocks reachable from the entry
// block.
// This list will be pruned down by the CloneFunction() due to two
// two optimizations:
// First, when a conditional branch target is known at compile-time,
// only the actual branch destination block needs to be cloned.
// Second, when a switch statement target is known at compile-time,
// only the actual case statement needs to be cloned.
std::set<const BasicBlock *> OrigBBs;
CloneWorklist.push_back(&OldFunc->getEntryBlock()); CloneWorklist.push_back(&OldFunc->getEntryBlock());
while (!CloneWorklist.empty()) { while (!CloneWorklist.empty()) {
const BasicBlock *BB = CloneWorklist.back(); const BasicBlock *BB = CloneWorklist.back();
CloneWorklist.pop_back(); CloneWorklist.pop_back();
PFC.CloneBlock(BB, CloneWorklist);
// Don't revisit blocks.
if (VMap.count(BB))
continue;
BasicBlock *NewBB = BasicBlock::Create(BB->getContext());
if (BB->hasName())
NewBB->setName(BB->getName() + NameSuffix);
// It is legal to clone a function when a block address within that
// function is never escapes outside of the function. Given that, we
// want to map block addresses from the old function to block addresses in
// the clone. (This is different from the generic ValueMapper
// implementation, which generates an invalid block address when
// cloning a function.)
// Note the current escape address does not catch all legal cases: even
// when all block addresses taken are local and the function has the
// always_inline attribute due to the indirect branch inlining is
// suppressed.
// Note that we don't need to fix the mapping for unreachable blocks;
// the default mapping there is safe.
if (BB->hasAddressTaken()) {
Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
const_cast<BasicBlock*>(BB));
VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
}
OrigBBs.insert(BB);
VMap[BB] = NewBB;
// Iterate over all possible successors and add them to the CloneWorklist.
const TerminatorInst *Term = BB->getTerminator();
for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
BasicBlock *Succ = Term->getSuccessor(i);
CloneWorklist.push_back(Succ);
}
} }
// Now, fill only the reachable blocks with the cloned contents
// of the originals.
assert(CloneWorklist.empty() && "Dirty worklist before re-use\n");
CloneWorklist.push_back(&OldFunc->getEntryBlock());
while (!CloneWorklist.empty()) {
const BasicBlock *BB = CloneWorklist.back();
CloneWorklist.pop_back();
PFC.CloneBlock(BB, cast<BasicBlock>(VMap[BB]), CloneWorklist,
OrigBBs);
}
// FIXME: Delete BB's that were created but have been pruned.
// Actual cloning may have found pruning opportunities since
// branch or switch statement target may have been known at compile-time.
// Alternatively we could write a routine CloneFunction and add a) a
// parameter to actually do the cloning and b) a return parameter that
// gives a list of blocks that need to be cloned also. Then we could
// call CloneFunction when we collect the blocks to clone, but suppress
// cloning. And then actually *do* the cloning in the while loop above. Then
// the cleanup here would become redundant, and so would be the OrigBBs.
for (std::set<const BasicBlock *>::iterator Oi = OrigBBs.begin(),
Oe = OrigBBs.end(); Oi != Oe; ++Oi) {
const BasicBlock *Orig = *Oi;
BasicBlock *NewBB = cast<BasicBlock>(VMap[Orig]);
delete NewBB;
VMap[Orig] = 0;
}
// Loop over all of the basic blocks in the old function. If the block was // Loop over all of the basic blocks in the old function. If the block was
// reachable, we have cloned it and the old block is now in the value map: // reachable, we have cloned it and the old block is now in the value map:
// insert it into the new function in the right order. If not, ignore it. // insert it into the new function in the right order. If not, ignore it.
@ -525,8 +454,7 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
BI != BE; ++BI) { BI != BE; ++BI) {
Value *V = VMap[BI]; Value *V = VMap[BI];
BasicBlock *NewBB = cast_or_null<BasicBlock>(V); BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
if (!NewBB) if (!NewBB) continue; // Dead block.
continue; // Dead block.
// Add the new block to the new function. // Add the new block to the new function.
NewFunc->getBasicBlockList().push_back(NewBB); NewFunc->getBasicBlockList().push_back(NewBB);