[llvm-commits] [llvm] r149318 - /llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
Bill Wendling
isanbard at gmail.com
Mon Jan 30 17:18:21 PST 2012
Author: void
Date: Mon Jan 30 19:18:21 2012
New Revision: 149318
URL: http://llvm.org/viewvc/llvm-project?rev=149318&view=rev
Log:
Remove more dead functions.
Modified:
llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=149318&r1=149317&r2=149318&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Mon Jan 30 19:18:21 2012
@@ -10,13 +10,6 @@
// This file implements inlining of a function into a call site, resolving
// parameters and the return value as appropriate.
//
-// The code in this file for handling inlines through invoke
-// instructions preserves semantics only under some assumptions about
-// the behavior of unwinders which correspond to gcc-style libUnwind
-// exception personality functions. Eventually the IR will be
-// improved to make this unnecessary, but until then, this code is
-// marked [LIBUNWIND].
-//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
@@ -45,204 +38,6 @@
return InlineFunction(CallSite(II), IFI);
}
-// FIXME: New EH - Remove the functions marked [LIBUNWIND] when new EH is
-// turned on.
-
-/// [LIBUNWIND] Look for an llvm.eh.exception call in the given block.
-static EHExceptionInst *findExceptionInBlock(BasicBlock *bb) {
- for (BasicBlock::iterator i = bb->begin(), e = bb->end(); i != e; i++) {
- EHExceptionInst *exn = dyn_cast<EHExceptionInst>(i);
- if (exn) return exn;
- }
-
- return 0;
-}
-
-/// [LIBUNWIND] Look for the 'best' llvm.eh.selector instruction for
-/// the given llvm.eh.exception call.
-static EHSelectorInst *findSelectorForException(EHExceptionInst *exn) {
- BasicBlock *exnBlock = exn->getParent();
-
- EHSelectorInst *outOfBlockSelector = 0;
- for (Instruction::use_iterator
- ui = exn->use_begin(), ue = exn->use_end(); ui != ue; ++ui) {
- EHSelectorInst *sel = dyn_cast<EHSelectorInst>(*ui);
- if (!sel) continue;
-
- // Immediately accept an eh.selector in the same block as the
- // excepton call.
- if (sel->getParent() == exnBlock) return sel;
-
- // Otherwise, use the first selector we see.
- if (!outOfBlockSelector) outOfBlockSelector = sel;
- }
-
- return outOfBlockSelector;
-}
-
-/// [LIBUNWIND] Find the (possibly absent) call to @llvm.eh.selector
-/// in the given landing pad. In principle, llvm.eh.exception is
-/// required to be in the landing pad; in practice, SplitCriticalEdge
-/// can break that invariant, and then inlining can break it further.
-/// There's a real need for a reliable solution here, but until that
-/// happens, we have some fragile workarounds here.
-static EHSelectorInst *findSelectorForLandingPad(BasicBlock *lpad) {
- // Look for an exception call in the actual landing pad.
- EHExceptionInst *exn = findExceptionInBlock(lpad);
- if (exn) return findSelectorForException(exn);
-
- // Okay, if that failed, look for one in an obvious successor. If
- // we find one, we'll fix the IR by moving things back to the
- // landing pad.
-
- bool dominates = true; // does the lpad dominate the exn call
- BasicBlock *nonDominated = 0; // if not, the first non-dominated block
- BasicBlock *lastDominated = 0; // and the block which branched to it
-
- BasicBlock *exnBlock = lpad;
-
- // We need to protect against lpads that lead into infinite loops.
- SmallPtrSet<BasicBlock*,4> visited;
- visited.insert(exnBlock);
-
- do {
- // We're not going to apply this hack to anything more complicated
- // than a series of unconditional branches, so if the block
- // doesn't terminate in an unconditional branch, just fail. More
- // complicated cases can arise when, say, sinking a call into a
- // split unwind edge and then inlining it; but that can do almost
- // *anything* to the CFG, including leaving the selector
- // completely unreachable. The only way to fix that properly is
- // to (1) prohibit transforms which move the exception or selector
- // values away from the landing pad, e.g. by producing them with
- // instructions that are pinned to an edge like a phi, or
- // producing them with not-really-instructions, and (2) making
- // transforms which split edges deal with that.
- BranchInst *branch = dyn_cast<BranchInst>(&exnBlock->back());
- if (!branch || branch->isConditional()) return 0;
-
- BasicBlock *successor = branch->getSuccessor(0);
-
- // Fail if we found an infinite loop.
- if (!visited.insert(successor)) return 0;
-
- // If the successor isn't dominated by exnBlock:
- if (!successor->getSinglePredecessor()) {
- // We don't want to have to deal with threading the exception
- // through multiple levels of phi, so give up if we've already
- // followed a non-dominating edge.
- if (!dominates) return 0;
-
- // Otherwise, remember this as a non-dominating edge.
- dominates = false;
- nonDominated = successor;
- lastDominated = exnBlock;
- }
-
- exnBlock = successor;
-
- // Can we stop here?
- exn = findExceptionInBlock(exnBlock);
- } while (!exn);
-
- // Look for a selector call for the exception we found.
- EHSelectorInst *selector = findSelectorForException(exn);
- if (!selector) return 0;
-
- // The easy case is when the landing pad still dominates the
- // exception call, in which case we can just move both calls back to
- // the landing pad.
- if (dominates) {
- selector->moveBefore(lpad->getFirstNonPHI());
- exn->moveBefore(selector);
- return selector;
- }
-
- // Otherwise, we have to split at the first non-dominating block.
- // The CFG looks basically like this:
- // lpad:
- // phis_0
- // insnsAndBranches_1
- // br label %nonDominated
- // nonDominated:
- // phis_2
- // insns_3
- // %exn = call i8* @llvm.eh.exception()
- // insnsAndBranches_4
- // %selector = call @llvm.eh.selector(i8* %exn, ...
- // We need to turn this into:
- // lpad:
- // phis_0
- // %exn0 = call i8* @llvm.eh.exception()
- // %selector0 = call @llvm.eh.selector(i8* %exn0, ...
- // insnsAndBranches_1
- // br label %split // from lastDominated
- // nonDominated:
- // phis_2 (without edge from lastDominated)
- // %exn1 = call i8* @llvm.eh.exception()
- // %selector1 = call i8* @llvm.eh.selector(i8* %exn1, ...
- // br label %split
- // split:
- // phis_2 (edge from lastDominated, edge from split)
- // %exn = phi ...
- // %selector = phi ...
- // insns_3
- // insnsAndBranches_4
-
- assert(nonDominated);
- assert(lastDominated);
-
- // First, make clones of the intrinsics to go in lpad.
- EHExceptionInst *lpadExn = cast<EHExceptionInst>(exn->clone());
- EHSelectorInst *lpadSelector = cast<EHSelectorInst>(selector->clone());
- lpadSelector->setArgOperand(0, lpadExn);
- lpadSelector->insertBefore(lpad->getFirstNonPHI());
- lpadExn->insertBefore(lpadSelector);
-
- // Split the non-dominated block.
- BasicBlock *split =
- nonDominated->splitBasicBlock(nonDominated->getFirstNonPHI(),
- nonDominated->getName() + ".lpad-fix");
-
- // Redirect the last dominated branch there.
- cast<BranchInst>(lastDominated->back()).setSuccessor(0, split);
-
- // Move the existing intrinsics to the end of the old block.
- selector->moveBefore(&nonDominated->back());
- exn->moveBefore(selector);
-
- Instruction *splitIP = &split->front();
-
- // For all the phis in nonDominated, make a new phi in split to join
- // that phi with the edge from lastDominated.
- for (BasicBlock::iterator
- i = nonDominated->begin(), e = nonDominated->end(); i != e; ++i) {
- PHINode *phi = dyn_cast<PHINode>(i);
- if (!phi) break;
-
- PHINode *splitPhi = PHINode::Create(phi->getType(), 2, phi->getName(),
- splitIP);
- phi->replaceAllUsesWith(splitPhi);
- splitPhi->addIncoming(phi, nonDominated);
- splitPhi->addIncoming(phi->removeIncomingValue(lastDominated),
- lastDominated);
- }
-
- // Make new phis for the exception and selector.
- PHINode *exnPhi = PHINode::Create(exn->getType(), 2, "", splitIP);
- exn->replaceAllUsesWith(exnPhi);
- selector->setArgOperand(0, exn); // except for this use
- exnPhi->addIncoming(exn, nonDominated);
- exnPhi->addIncoming(lpadExn, lastDominated);
-
- PHINode *selectorPhi = PHINode::Create(selector->getType(), 2, "", splitIP);
- selector->replaceAllUsesWith(selectorPhi);
- selectorPhi->addIncoming(selector, nonDominated);
- selectorPhi->addIncoming(lpadSelector, lastDominated);
-
- return lpadSelector;
-}
-
namespace {
/// A class for recording information about inlining through an invoke.
class InvokeInliningInfo {
@@ -285,12 +80,6 @@
return OuterUnwindDest;
}
- EHSelectorInst *getOuterSelector() {
- if (!OuterSelector)
- OuterSelector = findSelectorForLandingPad(OuterUnwindDest);
- return OuterSelector;
- }
-
BasicBlock *getInnerUnwindDest();
LandingPadInst *getLandingPadInst() const { return CallerLPad; }
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