From f9969a3d28e738e9427e371aac06d71269220123 Mon Sep 17 00:00:00 2001 From: Yuanfang Chen Date: Mon, 22 Aug 2022 15:59:51 -0700 Subject: [PATCH] [CodeGen] Sort llvm.global_ctors by lexing order before emission Fixes https://github.com/llvm/llvm-project/issues/55804 The lexing order is already bookkept in DelayedCXXInitPosition but we were not using it based on the wrong assumption that inline variable is unordered. This patch fixes it by ordering entries in llvm.global_ctors by orders in DelayedCXXInitPosition. for llvm.global_ctors entries without a lexing order, ordering them by the insertion order. (This *mostly* orders the template instantiation in https://reviews.llvm.org/D126341 intuitively, minus one tweak for which I'll submit a separate patch.) Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D127233 --- clang/lib/CodeGen/CGDeclCXX.cpp | 14 +++-- clang/lib/CodeGen/CodeGenModule.cpp | 9 +++- clang/lib/CodeGen/CodeGenModule.h | 10 ++-- clang/lib/CodeGen/ItaniumCXXABI.cpp | 2 +- .../static-init-inline-variable.cpp | 52 +++++++++++++++++++ 5 files changed, 78 insertions(+), 9 deletions(-) create mode 100644 clang/test/CodeGenCXX/static-init-inline-variable.cpp diff --git a/clang/lib/CodeGen/CGDeclCXX.cpp b/clang/lib/CodeGen/CGDeclCXX.cpp index 8ceb4863d6ea..207585784865 100644 --- a/clang/lib/CodeGen/CGDeclCXX.cpp +++ b/clang/lib/CodeGen/CGDeclCXX.cpp @@ -562,7 +562,7 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D, Priority = 400; if (Priority != -1) - AddGlobalCtor(Fn, Priority, COMDATKey); + AddGlobalCtor(Fn, Priority, ~0U, COMDATKey); else EmitPointerToInitFunc(D, Addr, Fn, ISA); } else if (auto *IPA = D->getAttr()) { @@ -588,8 +588,16 @@ CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D, // SelectAny globals will be comdat-folded. Put the initializer into a // COMDAT group associated with the global, so the initializers get folded // too. - - AddGlobalCtor(Fn, 65535, COMDATKey); + I = DelayedCXXInitPosition.find(D); + // CXXGlobalInits.size() is the lex order number for the next deferred + // VarDecl. Use it when the current VarDecl is non-deferred. Although this + // lex order number is shared between current VarDecl and some following + // VarDecls, their order of insertion into `llvm.global_ctors` is the same + // as the lexing order and the following stable sort would preserve such + // order. + unsigned LexOrder = + I == DelayedCXXInitPosition.end() ? CXXGlobalInits.size() : I->second; + AddGlobalCtor(Fn, 65535, LexOrder, COMDATKey); if (COMDATKey && (getTriple().isOSBinFormatELF() || getTarget().getCXXABI().isMicrosoft())) { // When COMDAT is used on ELF or in the MS C++ ABI, the key must be in diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 9b97e890c352..74c14fed6575 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -47,6 +47,7 @@ #include "clang/CodeGen/BackendUtil.h" #include "clang/CodeGen/ConstantInitBuilder.h" #include "clang/Frontend/FrontendDiagnostic.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringSwitch.h" #include "llvm/ADT/Triple.h" #include "llvm/Analysis/TargetLibraryInfo.h" @@ -560,6 +561,9 @@ void CodeGenModule::Release() { if (PGOStats.hasDiagnostics()) PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName); } + llvm::stable_sort(GlobalCtors, [](const Structor &L, const Structor &R) { + return L.LexOrder < R.LexOrder; + }); EmitCtorList(GlobalCtors, "llvm.global_ctors"); EmitCtorList(GlobalDtors, "llvm.global_dtors"); EmitGlobalAnnotations(); @@ -1579,9 +1583,10 @@ llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) { /// AddGlobalCtor - Add a function to the list that will be called before /// main() runs. void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority, + unsigned LexOrder, llvm::Constant *AssociatedData) { // FIXME: Type coercion of void()* types. - GlobalCtors.push_back(Structor(Priority, Ctor, AssociatedData)); + GlobalCtors.push_back(Structor(Priority, LexOrder, Ctor, AssociatedData)); } /// AddGlobalDtor - Add a function to the list that will be called @@ -1595,7 +1600,7 @@ void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority, } // FIXME: Type coercion of void()* types. - GlobalDtors.push_back(Structor(Priority, Dtor, nullptr)); + GlobalDtors.push_back(Structor(Priority, ~0U, Dtor, nullptr)); } void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) { diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h index 14c791f4bce5..f57afdca4942 100644 --- a/clang/lib/CodeGen/CodeGenModule.h +++ b/clang/lib/CodeGen/CodeGenModule.h @@ -282,12 +282,15 @@ class CodeGenModule : public CodeGenTypeCache { public: struct Structor { - Structor() : Priority(0), Initializer(nullptr), AssociatedData(nullptr) {} - Structor(int Priority, llvm::Constant *Initializer, + Structor() + : Priority(0), LexOrder(~0u), Initializer(nullptr), + AssociatedData(nullptr) {} + Structor(int Priority, unsigned LexOrder, llvm::Constant *Initializer, llvm::Constant *AssociatedData) - : Priority(Priority), Initializer(Initializer), + : Priority(Priority), LexOrder(LexOrder), Initializer(Initializer), AssociatedData(AssociatedData) {} int Priority; + unsigned LexOrder; llvm::Constant *Initializer; llvm::Constant *AssociatedData; }; @@ -1602,6 +1605,7 @@ private: // FIXME: Hardcoding priority here is gross. void AddGlobalCtor(llvm::Function *Ctor, int Priority = 65535, + unsigned LexOrder = ~0U, llvm::Constant *AssociatedData = nullptr); void AddGlobalDtor(llvm::Function *Dtor, int Priority = 65535, bool IsDtorAttrFunc = false); diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp index 002a5edabe22..2809cbe99c10 100644 --- a/clang/lib/CodeGen/ItaniumCXXABI.cpp +++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -2687,7 +2687,7 @@ void CodeGenModule::registerGlobalDtorsWithAtExit() { } CGF.FinishFunction(); - AddGlobalCtor(GlobalInitFn, Priority, nullptr); + AddGlobalCtor(GlobalInitFn, Priority); } if (getCXXABI().useSinitAndSterm()) diff --git a/clang/test/CodeGenCXX/static-init-inline-variable.cpp b/clang/test/CodeGenCXX/static-init-inline-variable.cpp new file mode 100644 index 000000000000..873e32544c7e --- /dev/null +++ b/clang/test/CodeGenCXX/static-init-inline-variable.cpp @@ -0,0 +1,52 @@ +// RUN: %clang_cc1 -std=c++17 -S -emit-llvm -disable-llvm-passes -o - %s -triple x86_64-linux-gnu | FileCheck %s + +struct A { + int x; + A(int x) : x(x) {} + ~A() {} +}; + +namespace DeferredSequence { +inline int a = 1; +inline int b = a + 1; +inline int c = b + 1; +inline int d = c + 1; +int e = d; +} + +namespace MixedSequence { +inline A a(1); +inline int x = a.x + 1; +inline int y = x + 1; +inline A b(y); +inline int z = b.x + 1; +inline int w = z + 1; +inline A c(b.x); +inline A d(c.x); +int t = w; +} + +namespace NonDeferredSequence { +inline A a(1); +inline A b(a.x); +inline A c(b.x); +inline A d(c.x); +} + +// CHECK: @llvm.global_ctors = appending global [16 x { i32, ptr, ptr }] [ +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.12, ptr @_ZN16DeferredSequence1bE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.11, ptr @_ZN16DeferredSequence1cE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.10, ptr @_ZN16DeferredSequence1dE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.1, ptr @_ZN13MixedSequence1aE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.14, ptr @_ZN13MixedSequence1xE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.13, ptr @_ZN13MixedSequence1yE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.2, ptr @_ZN13MixedSequence1bE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.16, ptr @_ZN13MixedSequence1zE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.15, ptr @_ZN13MixedSequence1wE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.3, ptr @_ZN13MixedSequence1cE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.4, ptr @_ZN13MixedSequence1dE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.6, ptr @_ZN19NonDeferredSequence1aE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.7, ptr @_ZN19NonDeferredSequence1bE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.8, ptr @_ZN19NonDeferredSequence1cE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @__cxx_global_var_init.9, ptr @_ZN19NonDeferredSequence1dE }, +// CHECK-SAME: { i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_static_init_inline_variable.cpp, ptr null }