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-rw-r--r--llvm/include/llvm/Linker/Linker.h5
-rw-r--r--llvm/include/llvm/Transforms/IPO/FunctionImport.h6
-rw-r--r--llvm/lib/Linker/LinkModules.cpp9
-rw-r--r--llvm/lib/Transforms/IPO/FunctionImport.cpp20
-rw-r--r--llvm/test/Linker/funcimport2.ll2
-rw-r--r--llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll42
-rw-r--r--llvm/test/Transforms/FunctionImport/funcimport.ll18
-rw-r--r--llvm/tools/llvm-link/llvm-link.cpp6
8 files changed, 96 insertions, 12 deletions
diff --git a/llvm/include/llvm/Linker/Linker.h b/llvm/include/llvm/Linker/Linker.h
index e1605cb0f32..b077c373326 100644
--- a/llvm/include/llvm/Linker/Linker.h
+++ b/llvm/include/llvm/Linker/Linker.h
@@ -29,7 +29,10 @@ public:
None = 0,
OverrideFromSrc = (1 << 0),
LinkOnlyNeeded = (1 << 1),
- InternalizeLinkedSymbols = (1 << 2)
+ InternalizeLinkedSymbols = (1 << 2),
+ /// Don't force link referenced linkonce definitions, import declaration.
+ DontForceLinkLinkonceODR = (1 << 3)
+
};
Linker(Module &M);
diff --git a/llvm/include/llvm/Transforms/IPO/FunctionImport.h b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
index 253c5df8701..95230ea9e78 100644
--- a/llvm/include/llvm/Transforms/IPO/FunctionImport.h
+++ b/llvm/include/llvm/Transforms/IPO/FunctionImport.h
@@ -48,7 +48,11 @@ public:
: Index(Index), ModuleLoader(ModuleLoader) {}
/// Import functions in Module \p M based on the supplied import list.
- bool importFunctions(Module &M, const ImportMapTy &ImportList);
+ /// \p ForceImportReferencedDiscardableSymbols will set the ModuleLinker in
+ /// a mode where referenced discarable symbols in the source modules will be
+ /// imported as well even if they are not present in the ImportList.
+ bool importFunctions(Module &M, const ImportMapTy &ImportList,
+ bool ForceImportReferencedDiscardableSymbols = false);
private:
/// The summaries index used to trigger importing.
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index cd3cd52f7ad..8ed885649ca 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -45,6 +45,9 @@ class ModuleLinker {
/// to Add.
void addLazyFor(GlobalValue &GV, IRMover::ValueAdder Add);
+ bool shouldLinkReferencedLinkOnce() {
+ return !(Flags & Linker::DontForceLinkLinkonceODR);
+ }
bool shouldOverrideFromSrc() { return Flags & Linker::OverrideFromSrc; }
bool shouldLinkOnlyNeeded() { return Flags & Linker::LinkOnlyNeeded; }
bool shouldInternalizeLinkedSymbols() {
@@ -413,6 +416,12 @@ bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
}
void ModuleLinker::addLazyFor(GlobalValue &GV, IRMover::ValueAdder Add) {
+ if (!shouldLinkReferencedLinkOnce())
+ // For ThinLTO we don't import more than what was required.
+ // The client has to guarantee that the linkonce will be availabe at link
+ // time (by promoting it to weak for instance).
+ return;
+
// Add these to the internalize list
if (!GV.hasLinkOnceLinkage())
return;
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 9d7d78a30a1..25d413030f4 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -49,6 +49,12 @@ static cl::opt<float>
static cl::opt<bool> PrintImports("print-imports", cl::init(false), cl::Hidden,
cl::desc("Print imported functions"));
+// Temporary allows the function import pass to disable always linking
+// referenced discardable symbols.
+static cl::opt<bool>
+ DontForceImportReferencedDiscardableSymbols("disable-force-link-odr",
+ cl::init(false), cl::Hidden);
+
// Load lazily a module from \p FileName in \p Context.
static std::unique_ptr<Module> loadFile(const std::string &FileName,
LLVMContext &Context) {
@@ -327,7 +333,8 @@ void llvm::ComputeCrossModuleImportForModule(
// index.
//
bool FunctionImporter::importFunctions(
- Module &DestModule, const FunctionImporter::ImportMapTy &ImportList) {
+ Module &DestModule, const FunctionImporter::ImportMapTy &ImportList,
+ bool ForceImportReferencedDiscardableSymbols) {
DEBUG(dbgs() << "Starting import for Module "
<< DestModule.getModuleIdentifier() << "\n");
unsigned ImportedCount = 0;
@@ -420,8 +427,12 @@ bool FunctionImporter::importFunctions(
<< " from " << SrcModule->getSourceFileName() << "\n";
}
- if (TheLinker.linkInModule(std::move(SrcModule), Linker::Flags::None,
- &GlobalsToImport))
+ // Instruct the linker that the client will take care of linkonce resolution
+ unsigned Flags = Linker::Flags::None;
+ if (!ForceImportReferencedDiscardableSymbols)
+ Flags |= Linker::Flags::DontForceLinkLinkonceODR;
+
+ if (TheLinker.linkInModule(std::move(SrcModule), Flags, &GlobalsToImport))
report_fatal_error("Function Import: link error");
ImportedCount += GlobalsToImport.size();
@@ -523,7 +534,8 @@ public:
return loadFile(Identifier, M.getContext());
};
FunctionImporter Importer(*Index, ModuleLoader);
- return Importer.importFunctions(M, ImportList);
+ return Importer.importFunctions(
+ M, ImportList, !DontForceImportReferencedDiscardableSymbols);
}
};
} // anonymous namespace
diff --git a/llvm/test/Linker/funcimport2.ll b/llvm/test/Linker/funcimport2.ll
index 6c30dda0d85..bf8f96b78da 100644
--- a/llvm/test/Linker/funcimport2.ll
+++ b/llvm/test/Linker/funcimport2.ll
@@ -3,7 +3,7 @@
; RUN: llvm-lto -thinlto -o %t3 %t1.bc %t2.bc
; RUN: llvm-link -import=bar:%t2.bc %t1.bc -summary-index=%t3.thinlto.bc -S | FileCheck %s
-; CHECK: define linkonce_odr hidden void @foo() {
+; CHECK: define available_externally hidden void @foo() {
define available_externally hidden void @foo() {
ret void
}
diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
index 79b766b386d..03ea3647fd7 100644
--- a/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
@@ -99,4 +99,46 @@ entry:
ret void
}
+define void @referencelargelinkonce() #0 {
+entry:
+ call void @linkonceodr()
+ ret void
+}
+
+; A large enough linkonce_odr function that should never be imported
+define linkonce_odr void @linkonceodr() #0 {
+entry:
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ call void @globalfunc2()
+ ret void
+}
+
diff --git a/llvm/test/Transforms/FunctionImport/funcimport.ll b/llvm/test/Transforms/FunctionImport/funcimport.ll
index 8e059ca59a7..f0df3200555 100644
--- a/llvm/test/Transforms/FunctionImport/funcimport.ll
+++ b/llvm/test/Transforms/FunctionImport/funcimport.ll
@@ -4,14 +4,19 @@
; RUN: llvm-lto -thinlto -print-summary-global-ids -o %t3 %t.bc %t2.bc 2>&1 | FileCheck %s --check-prefix=GUID
; Do the import now
-; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIMDEF
+; RUN: opt -disable-force-link-odr -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIMDEF
; "-stats" requires +Asserts.
; REQUIRES: asserts
; Test import with smaller instruction limit
-; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIM5
+; RUN: opt -disable-force-link-odr -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIM5
; INSTLIM5-NOT: @staticfunc.llvm.
+; Test import with smaller instruction limit and without the -disable-force-link-odr
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=INSTLIM5ODR
+; INSTLIM5ODR: define linkonce_odr void @linkonceodr()
+
+
define i32 @main() #0 {
entry:
call void (...) @weakalias()
@@ -23,6 +28,7 @@ entry:
call void (...) @setfuncptr()
call void (...) @callfuncptr()
call void (...) @weakfunc()
+ call void (...) @referencelargelinkonce()
ret i32 0
}
@@ -78,6 +84,12 @@ declare void @callfuncptr(...) #1
; CHECK-DAG: %0 = load void ()*, void ()** @P.llvm.
; CHECK-DAG: store void ()* @staticfunc2.llvm.{{.*}}, void ()** @P.llvm.
+; Ensure that @referencelargelinkonce definition is pulled in, but later we
+; also check that the linkonceodr function is not.
+; CHECK-DAG: define available_externally void @referencelargelinkonce()
+; INSTLIM5-DAG: declare void @linkonceodr()
+declare void @referencelargelinkonce(...)
+
; Won't import weak func
; CHECK-DAG: declare void @weakfunc(...)
declare void @weakfunc(...) #1
@@ -87,7 +99,7 @@ declare void @weakfunc(...) #1
; INSTLIM5-DAG: declare hidden void @funcwithpersonality.llvm.{{.*}}()
; INSTLIMDEF-DAG: Import globalfunc2
-; INSTLIMDEF-DAG: 11 function-import - Number of functions imported
+; INSTLIMDEF-DAG: 13 function-import - Number of functions imported
; The actual GUID values will depend on path to test.
; GUID-DAG: GUID {{.*}} is weakalias
diff --git a/llvm/tools/llvm-link/llvm-link.cpp b/llvm/tools/llvm-link/llvm-link.cpp
index 73ac8727e71..0e720bd06ea 100644
--- a/llvm/tools/llvm-link/llvm-link.cpp
+++ b/llvm/tools/llvm-link/llvm-link.cpp
@@ -276,8 +276,10 @@ static bool importFunctions(const char *argv0, LLVMContext &Context,
if (renameModuleForThinLTO(*SrcModule, *Index, &GlobalsToImport))
return true;
- if (L.linkInModule(std::move(SrcModule), Linker::Flags::None,
- &GlobalsToImport))
+ // Instruct the linker to not automatically import linkonce defintion.
+ unsigned Flags = Linker::Flags::DontForceLinkLinkonceODR;
+
+ if (L.linkInModule(std::move(SrcModule), Flags, &GlobalsToImport))
return false;
}
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