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-rw-r--r--lib/Transforms/Utils/InlineFunction.cpp212
-rw-r--r--test/Transforms/Inline/inline_invoke.ll93
2 files changed, 276 insertions, 29 deletions
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index e69dc89fd0..8416170d90 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -45,31 +45,199 @@ bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI) {
return InlineFunction(CallSite(II), IFI);
}
-/// [LIBUNWIND] Find the (possibly absent) call to @llvm.eh.selector in
-/// the given landing pad.
-static EHSelectorInst *findSelectorForLandingPad(BasicBlock *lpad) {
- // The llvm.eh.exception call is required to be in the landing pad.
- for (BasicBlock::iterator i = lpad->begin(), e = lpad->end(); i != e; i++) {
+/// [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) continue;
+ 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 *selector = 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;
+ 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 landing pad.
- if (sel->getParent() == lpad) return sel;
+ // 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 (!selector) selector = 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;
}
- return 0;
+ // 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 {
@@ -726,18 +894,6 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI) {
// Leave lifetime markers for the static alloca's, scoping them to the
// function we just inlined.
if (!IFI.StaticAllocas.empty()) {
- // Also preserve the call graph, if applicable.
- CallGraphNode *StartCGN = 0, *EndCGN = 0, *CallerNode = 0;
- if (CallGraph *CG = IFI.CG) {
- Function *Start = Intrinsic::getDeclaration(Caller->getParent(),
- Intrinsic::lifetime_start);
- Function *End = Intrinsic::getDeclaration(Caller->getParent(),
- Intrinsic::lifetime_end);
- StartCGN = CG->getOrInsertFunction(Start);
- EndCGN = CG->getOrInsertFunction(End);
- CallerNode = (*CG)[Caller];
- }
-
IRBuilder<> builder(FirstNewBlock->begin());
for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
AllocaInst *AI = IFI.StaticAllocas[ai];
diff --git a/test/Transforms/Inline/inline_invoke.ll b/test/Transforms/Inline/inline_invoke.ll
index 5f657387c2..2a1b8836c7 100644
--- a/test/Transforms/Inline/inline_invoke.ll
+++ b/test/Transforms/Inline/inline_invoke.ll
@@ -16,6 +16,8 @@ declare void @_ZN1AD1Ev(%struct.A*)
declare void @use(i32) nounwind
+declare void @opaque()
+
declare i8* @llvm.eh.exception() nounwind readonly
declare i32 @llvm.eh.selector(i8*, i8*, ...) nounwind
@@ -217,8 +219,8 @@ eh.resume:
; CHECK: call void @llvm.eh.resume(i8* [[EXNJ1]], i32 [[SELJ1]])
-;; Test 2 - Don't make invalid IR for inlines into landing pads without eh.exception calls
+;; Test 2 - Don't make invalid IR for inlines into landing pads without eh.exception calls
define void @test2_out() uwtable ssp {
entry:
invoke void @test0_in()
@@ -243,3 +245,92 @@ lpad:
; CHECK-NEXT: unwind label %[[LPAD2]]
; CHECK: invoke void @_ZN1AD1Ev(%struct.A* [[A]])
; CHECK-NEXT: unwind label %[[LPAD]]
+
+
+;; Test 3 - Deal correctly with split unwind edges.
+define void @test3_out() uwtable ssp {
+entry:
+ invoke void @test0_in()
+ to label %ret unwind label %lpad
+
+ret:
+ ret void
+
+lpad:
+ br label %lpad.cont
+
+lpad.cont:
+ %exn = call i8* @llvm.eh.exception() nounwind
+ %eh.selector = call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* %exn, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*)) nounwind
+ call void @_ZSt9terminatev()
+ unreachable
+}
+
+; CHECK: define void @test3_out()
+; CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* {{%.*}}, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i32 0, i8* bitcast (i8** @_ZTIi to i8*))
+; CHECK-NEXT: invoke void @_ZN1AD1Ev(
+; CHECK-NEXT: to label %[[L:[^\s]+]] unwind
+; CHECK: [[L]]:
+; CHECK-NEXT: br label %[[JOIN:[^\s]+]]
+; CHECK: [[JOIN]]:
+; CHECK-NEXT: phi
+; CHECK-NEXT: phi
+; CHECK-NEXT: br label %lpad.cont
+; CHECK: lpad.cont:
+; CHECK-NEXT: call void @_ZSt9terminatev()
+
+
+;; Test 4 - Split unwind edges with a dominance problem
+define void @test4_out() uwtable ssp {
+entry:
+ invoke void @test0_in()
+ to label %cont unwind label %lpad.crit
+
+cont:
+ invoke void @opaque()
+ to label %ret unwind label %lpad
+
+ret:
+ ret void
+
+lpad.crit:
+ call void @opaque() nounwind
+ br label %lpad
+
+lpad:
+ %phi = phi i32 [ 0, %lpad.crit ], [ 1, %cont ]
+ %exn = call i8* @llvm.eh.exception() nounwind
+ %eh.selector = call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* %exn, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*)) nounwind
+ call void @use(i32 %phi)
+ call void @_ZSt9terminatev()
+ unreachable
+}
+
+; CHECK: define void @test4_out()
+; CHECK: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* {{%.*}}, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i32 0, i8* bitcast (i8** @_ZTIi to i8*))
+; CHECK-NEXT: invoke void @_ZN1AD1Ev(
+; CHECK-NEXT: to label %[[L:[^\s]+]] unwind
+; CHECK: [[L]]:
+; CHECK-NEXT: br label %[[JOIN:[^\s]+]]
+; CHECK: invoke void @opaque()
+; CHECK-NEXT: unwind label %lpad
+; CHECK: lpad.crit:
+; CHECK-NEXT: call i8* @llvm.eh.exception()
+; CHECK-NEXT: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* %4, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*))
+; CHECK-NEXT: br label %[[JOIN]]
+; CHECK: [[JOIN]]:
+; CHECK-NEXT: phi i8*
+; CHECK-NEXT: phi i32
+; CHECK-NEXT: call void @opaque() nounwind
+; CHECK-NEXT: br label %[[FIX:[^\s]+]]
+; CHECK: lpad:
+; CHECK-NEXT: [[T0:%.*]] = phi i32 [ 1, %cont ]
+; CHECK-NEXT: call i8* @llvm.eh.exception() nounwind
+; CHECK-NEXT: call i32 (i8*, i8*, ...)* @llvm.eh.selector(i8* %exn, i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*), i8* bitcast (i8** @_ZTIi to i8*))
+; CHECK-NEXT: br label %[[FIX]]
+; CHECK: [[FIX]]:
+; CHECK-NEXT: [[T1:%.*]] = phi i32 [ [[T0]], %lpad ], [ 0, %[[JOIN]] ]
+; CHECK-NEXT: phi i8*
+; CHECK-NEXT: phi i32
+; CHECK-NEXT: call void @use(i32 [[T1]])
+; CHECK-NEXT: call void @_ZSt9terminatev()
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-08 10:17:54 +0000