diff options
| -rw-r--r-- | llvm/lib/Linker/LinkModules.cpp | 21 | ||||
| -rw-r--r-- | llvm/test/Linker/Inputs/only-needed-named-metadata.ll | 3 | ||||
| -rw-r--r-- | llvm/test/Linker/distinct.ll | 2 | ||||
| -rw-r--r-- | llvm/test/Linker/only-needed-named-metadata.ll | 69 |
4 files changed, 89 insertions, 6 deletions
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp index 74ca197ddb3..010c5611949 100644 --- a/llvm/lib/Linker/LinkModules.cpp +++ b/llvm/lib/Linker/LinkModules.cpp @@ -440,6 +440,11 @@ class ModuleLinker { /// as part of a different backend compilation process. bool HasExportedFunctions; + /// Set to true when all global value body linking is complete (including + /// lazy linking). Used to prevent metadata linking from creating new + /// references. + bool DoneLinkingBodies; + public: ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM, DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags, @@ -448,7 +453,8 @@ public: : DstM(dstM), SrcM(srcM), TypeMap(Set), ValMaterializer(TypeMap, DstM, LazilyLinkGlobalValues, this), DiagnosticHandler(DiagnosticHandler), Flags(Flags), ImportIndex(Index), - ImportFunction(FuncToImport), HasExportedFunctions(false) { + ImportFunction(FuncToImport), HasExportedFunctions(false), + DoneLinkingBodies(false) { assert((ImportIndex || !ImportFunction) && "Expect a FunctionInfoIndex when importing"); // If we have a FunctionInfoIndex but no function to import, @@ -475,6 +481,9 @@ public: /// Check if we should promote the given local value to global scope. bool doPromoteLocalToGlobal(const GlobalValue *SGV); + /// Check if all global value body linking is complete. + bool doneLinkingBodies() { return DoneLinkingBodies; } + private: bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest, const GlobalValue &Src); @@ -888,6 +897,12 @@ Value *ValueMaterializerTy::materializeValueFor(Value *V) { if (!SGV) return nullptr; + // If we are done linking global value bodies (i.e. we are performing + // metadata linking), don't link in the global value due to this + // reference, simply map it to null. + if (ModLinker->doneLinkingBodies()) + return nullptr; + GlobalValue *DGV = ModLinker->copyGlobalValueProto(TypeMap, SGV); if (Comdat *SC = SGV->getComdat()) { @@ -1918,6 +1933,10 @@ bool ModuleLinker::run() { return true; } + // Note that we are done linking global value bodies. This prevents + // metadata linking from creating new references. + DoneLinkingBodies = true; + // Remap all of the named MDNodes in Src into the DstM module. We do this // after linking GlobalValues so that MDNodes that reference GlobalValues // are properly remapped. diff --git a/llvm/test/Linker/Inputs/only-needed-named-metadata.ll b/llvm/test/Linker/Inputs/only-needed-named-metadata.ll index fa7bc2e3cc8..95151692d3b 100644 --- a/llvm/test/Linker/Inputs/only-needed-named-metadata.ll +++ b/llvm/test/Linker/Inputs/only-needed-named-metadata.ll @@ -2,8 +2,11 @@ declare i32 @foo() +declare void @c1_a() + define void @bar() { load i32, i32* @X call i32 @foo() + call void @c1_a() ret void } diff --git a/llvm/test/Linker/distinct.ll b/llvm/test/Linker/distinct.ll index c8e5c89eb09..d88d8ae16d9 100644 --- a/llvm/test/Linker/distinct.ll +++ b/llvm/test/Linker/distinct.ll @@ -6,6 +6,8 @@ ; CHECK: @global = linkonce global i32 0 @global = linkonce global i32 0 +; Add an external reference to @global so that it gets linked in. +@alias = alias i32, i32* @global ; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !0, !1, !2, !9, !10, !11, !12, !13, !14} !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8} diff --git a/llvm/test/Linker/only-needed-named-metadata.ll b/llvm/test/Linker/only-needed-named-metadata.ll index f64637d3c75..36b42590628 100644 --- a/llvm/test/Linker/only-needed-named-metadata.ll +++ b/llvm/test/Linker/only-needed-named-metadata.ll @@ -1,16 +1,75 @@ ; RUN: llvm-as %S/only-needed-named-metadata.ll -o %t.bc ; RUN: llvm-as %S/Inputs/only-needed-named-metadata.ll -o %t2.bc -; RUN: llvm-link -S -only-needed %t2.bc %t.bc | FileCheck %s -; RUN: llvm-link -S -internalize -only-needed %t2.bc %t.bc | FileCheck %s -; CHECK: @U = external global i32 -; CHECK: declare i32 @unused() +; Without -only-needed we should lazy link linkonce globals, and the +; metadata reference should not cause them to be linked. +; RUN: llvm-link -S %t2.bc %t.bc | FileCheck %s +; CHECK-NOT:@U_linkonce +; CHECK-NOT:@unused_linkonce() + +; With -only-needed the metadata references should not cause any of the +; otherwise unreferenced globals to be linked. This also ensures that the +; metadata references don't provoke the module linker to create declarations, +; which are illegal for aliases and globals in comdats. +; Note that doing -only-needed with the comdat shown below leads to a only +; part of the comdat group being linked, which is not technically correct. +; RUN: llvm-link -S -only-needed %t2.bc %t.bc | FileCheck %s -check-prefix=ONLYNEEDED +; RUN: llvm-link -S -internalize -only-needed %t2.bc %t.bc | FileCheck %s -check-prefix=ONLYNEEDED +; ONLYNEEDED-NOT:@U +; ONLYNEEDED-NOT:@U_linkonce +; ONLYNEEDED-NOT:@unused() +; ONLYNEEDED-NOT:@unused_linkonce() +; ONLYNEEDED-NOT:@linkoncealias +; ONLYNEEDED-NOT:@linkoncefunc2() +; ONLYNEEDED-NOT:@weakalias +; ONLYNEEDED-NOT:@globalfunc1() +; ONLYNEEDED-NOT:@analias +; ONLYNEEDED-NOT:@globalfunc2() +; ONLYNEEDED-NOT:@c1_c +; ONLYNEEDED-NOT:@c1() + +$c1 = comdat any +@c1_c = global i32 0, comdat($c1) +define void @c1() comdat { + ret void +} +define void @c1_a() comdat($c1) { + ret void +} @X = global i32 5 @U = global i32 6 +@U_linkonce = linkonce_odr hidden global i32 6 define i32 @foo() { ret i32 7 } define i32 @unused() { ret i32 8 } +define linkonce_odr hidden i32 @unused_linkonce() { ret i32 8 } +@linkoncealias = alias void (...), bitcast (void ()* @linkoncefunc2 to void (...)*) + +@weakalias = weak alias void (...), bitcast (void ()* @globalfunc1 to void (...)*) +@analias = alias void (...), bitcast (void ()* @globalfunc2 to void (...)*) + +define void @globalfunc1() #0 { +entry: + ret void +} + +define void @globalfunc2() #0 { +entry: + ret void +} + +$linkoncefunc2 = comdat any +define linkonce_odr void @linkoncefunc2() #0 comdat { +entry: + ret void +} -!llvm.named = !{!0, !1} +!llvm.named = !{!0, !1, !2, !3, !4, !5, !6, !7} !0 = !{i32 ()* @unused} !1 = !{i32* @U} +!2 = !{i32 ()* @unused_linkonce} +!3 = !{i32* @U_linkonce} +!4 = !{void (...)* @weakalias} +!5 = !{void (...)* @analias} +!6 = !{void (...)* @linkoncealias} +!7 = !{void ()* @c1} |
