diff options
| -rw-r--r-- | llvm/lib/Bitcode/Writer/ValueEnumerator.cpp | 24 | ||||
| -rw-r--r-- | llvm/test/Bitcode/mdnodes-distinct-nodes-first.ll | 18 |
2 files changed, 36 insertions, 6 deletions
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp index 4de0d261c57..72b0048b031 100644 --- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp +++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp @@ -647,6 +647,22 @@ void ValueEnumerator::EnumerateFunctionLocalMetadata( EnumerateValue(Local->getValue()); } +static unsigned getMetadataTypeOrder(const Metadata *MD) { + // Strings are emitted in bulk and must come first. + if (isa<MDString>(MD)) + return 0; + + // ConstantAsMetadata doesn't reference anything. We may as well shuffle it + // to the front since we can detect it. + auto *N = dyn_cast<MDNode>(MD); + if (!N) + return 1; + + // The reader is fast forward references for distinct node operands, but slow + // when uniqued operands are unresolved. + return N->isDistinct() ? 2 : 3; +} + void ValueEnumerator::organizeMetadata() { assert(MetadataMap.size() == MDs.size() && "Metadata map and vector out of sync"); @@ -668,14 +684,10 @@ void ValueEnumerator::organizeMetadata() { // be unique, the result of std::sort will be deterministic. There's no need // for std::stable_sort. std::sort(Order.begin(), Order.end(), [this](MDIndex LHS, MDIndex RHS) { - return std::make_tuple(LHS.F, !isa<MDString>(LHS.get(MDs)), LHS.ID) < - std::make_tuple(RHS.F, !isa<MDString>(RHS.get(MDs)), RHS.ID); + return std::make_tuple(LHS.F, getMetadataTypeOrder(LHS.get(MDs)), LHS.ID) < + std::make_tuple(RHS.F, getMetadataTypeOrder(RHS.get(MDs)), RHS.ID); }); - // Return early if nothing is moving to functions and there are no strings. - if (!Order.back().F && !isa<MDString>(Order.front().get(MDs))) - return; - // Rebuild MDs, index the metadata ranges for each function in FunctionMDs, // and fix up MetadataMap. std::vector<const Metadata *> OldMDs = std::move(MDs); diff --git a/llvm/test/Bitcode/mdnodes-distinct-nodes-first.ll b/llvm/test/Bitcode/mdnodes-distinct-nodes-first.ll new file mode 100644 index 00000000000..1d146817e6b --- /dev/null +++ b/llvm/test/Bitcode/mdnodes-distinct-nodes-first.ll @@ -0,0 +1,18 @@ +; RUN: llvm-as <%s | llvm-bcanalyzer -dump | FileCheck %s +; Check that distinct nodes are emitted before uniqued nodes, even if that +; breaks post-order traversals. + +; Nodes in this testcase are numbered to match how they are referenced in +; bitcode. !1 is referenced as opN=1. + +; CHECK: <DISTINCT_NODE op0=2/> +!1 = distinct !{!2} + +; CHECK-NEXT: <NODE op0=1/> +!2 = !{!1} + +; Note: named metadata nodes are not cannot reference null so their operands +; are numbered off-by-one. +; CHECK-NEXT: <NAME +; CHECK-NEXT: <NAMED_NODE op0=1/> +!named = !{!2} |
