[llvm] r266948 - ThinLTO/ModuleLinker: add a flag to not always pull-in linkonce when performing importing
Mehdi Amini via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 20 18:59:40 PDT 2016
Author: mehdi_amini
Date: Wed Apr 20 20:59:39 2016
New Revision: 266948
URL: http://llvm.org/viewvc/llvm-project?rev=266948&view=rev
Log:
ThinLTO/ModuleLinker: add a flag to not always pull-in linkonce when performing importing
Summary:
The function importer already decided what symbols need to be pulled
in. Also these magically added ones will not be in the export list
for the source module, which can confuse the internalizer for
instance.
Reviewers: tejohnson, rafael
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D19096
From: Mehdi Amini <mehdi.amini at apple.com>
Modified:
llvm/trunk/include/llvm/Linker/Linker.h
llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h
llvm/trunk/lib/Linker/LinkModules.cpp
llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
llvm/trunk/test/Linker/funcimport2.ll
llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll
llvm/trunk/test/Transforms/FunctionImport/funcimport.ll
llvm/trunk/tools/llvm-link/llvm-link.cpp
Modified: llvm/trunk/include/llvm/Linker/Linker.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Linker/Linker.h?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Linker/Linker.h (original)
+++ llvm/trunk/include/llvm/Linker/Linker.h Wed Apr 20 20:59:39 2016
@@ -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);
Modified: llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h (original)
+++ llvm/trunk/include/llvm/Transforms/IPO/FunctionImport.h Wed Apr 20 20:59:39 2016
@@ -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.
Modified: llvm/trunk/lib/Linker/LinkModules.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Linker/LinkModules.cpp?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/lib/Linker/LinkModules.cpp (original)
+++ llvm/trunk/lib/Linker/LinkModules.cpp Wed Apr 20 20:59:39 2016
@@ -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(GlobalVa
}
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;
Modified: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp Wed Apr 20 20:59:39 2016
@@ -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::ComputeCrossModuleImportForMo
// 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
Modified: llvm/trunk/test/Linker/funcimport2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Linker/funcimport2.ll?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/test/Linker/funcimport2.ll (original)
+++ llvm/trunk/test/Linker/funcimport2.ll Wed Apr 20 20:59:39 2016
@@ -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
}
Modified: llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll (original)
+++ llvm/trunk/test/Transforms/FunctionImport/Inputs/funcimport.ll Wed Apr 20 20:59:39 2016
@@ -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
+}
+
Modified: llvm/trunk/test/Transforms/FunctionImport/funcimport.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionImport/funcimport.ll?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionImport/funcimport.ll (original)
+++ llvm/trunk/test/Transforms/FunctionImport/funcimport.ll Wed Apr 20 20:59:39 2016
@@ -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
Modified: llvm/trunk/tools/llvm-link/llvm-link.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-link/llvm-link.cpp?rev=266948&r1=266947&r2=266948&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-link/llvm-link.cpp (original)
+++ llvm/trunk/tools/llvm-link/llvm-link.cpp Wed Apr 20 20:59:39 2016
@@ -276,8 +276,10 @@ static bool importFunctions(const char *
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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