return Index.getValueInfo(GUID);
}
+static bool shouldImportGlobal(const ValueInfo &VI,
+ const GVSummaryMapTy &DefinedGVSummaries) {
+ const auto &GVS = DefinedGVSummaries.find(VI.getGUID());
+ if (GVS == DefinedGVSummaries.end())
+ return true;
+ // We should not skip import if the module contains a definition with
+ // interposable linkage type. This is required for correctness in
+ // the situation with two following conditions:
+ // * the def with interposable linkage is non-prevailing,
+ // * there is a prevailing def available for import and marked read-only.
+ // In this case, the non-prevailing def will be converted to a declaration,
+ // while the prevailing one becomes internal, thus no definitions will be
+ // available for linking. In order to prevent undefined symbol link error,
+ // the prevailing definition must be imported.
+ // FIXME: Consider adding a check that the suitable prevailing definition
+ // exists and marked read-only.
+ if (VI.getSummaryList().size() > 1 &&
+ GlobalValue::isInterposableLinkage(GVS->second->linkage()))
+ return true;
+
+ return false;
+}
+
static void computeImportForReferencedGlobals(
const GlobalValueSummary &Summary, const ModuleSummaryIndex &Index,
const GVSummaryMapTy &DefinedGVSummaries,
FunctionImporter::ImportMapTy &ImportList,
StringMap<FunctionImporter::ExportSetTy> *ExportLists) {
for (auto &VI : Summary.refs()) {
- if (DefinedGVSummaries.count(VI.getGUID())) {
+ if (!shouldImportGlobal(VI, DefinedGVSummaries)) {
LLVM_DEBUG(
dbgs() << "Ref ignored! Target already in destination module.\n");
continue;
continue;
if (DefinedGVSummaries.count(VI.getGUID())) {
+ // FIXME: Consider not skipping import if the module contains
+ // a non-prevailing def with interposable linkage. The prevailing copy
+ // can safely be imported (see shouldImportGlobal()).
LLVM_DEBUG(dbgs() << "ignored! Target already in destination module.\n");
continue;
}
--- /dev/null
+; RUN: split-file %s %t.dir
+
+; RUN: opt -module-summary %t.dir/1.ll -o %t1.bc
+; RUN: opt -module-summary %t.dir/2.ll -o %t2.bc
+
+; RUN: llvm-lto2 run -save-temps %t1.bc %t2.bc -o %t.out \
+; RUN: -r=%t1.bc,main,plx \
+; RUN: -r=%t1.bc,G \
+; RUN: -r=%t2.bc,G,pl
+; RUN: llvm-dis %t.out.1.3.import.bc -o - | FileCheck %s
+; RUN: llvm-dis %t.out.2.3.import.bc -o - | FileCheck %s
+
+; Test that a non-prevailing def with interposable linkage doesn't prevent
+; importing a suitable definition from a prevailing module.
+
+; CHECK: @G = internal local_unnamed_addr global i32 42
+
+;--- 1.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@G = weak dso_local local_unnamed_addr global i32 0, align 4
+
+define dso_local i32 @main() local_unnamed_addr {
+ %1 = load i32, i32* @G, align 4
+ ret i32 %1
+}
+
+;--- 2.ll
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@G = dso_local local_unnamed_addr global i32 42, align 4