From e1b6b5290373073c95f6865ceaf76fa7848ecf44 Mon Sep 17 00:00:00 2001 From: Michael Gottesman Date: Tue, 5 Feb 2013 06:53:26 +0000 Subject: [PATCH] Add code to GlobalVariable.h so that global variables marked as externally_initialized return false for hasDefiniteInitializer and hasUniqueInitializer. rdar://12580965. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174345 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/IR/GlobalVariable.h | 11 ++++-- .../externally-initialized-global-ctr.ll | 35 +++++++++++++++++++ 2 files changed, 44 insertions(+), 2 deletions(-) create mode 100644 test/Transforms/GlobalOpt/externally-initialized-global-ctr.ll diff --git a/include/llvm/IR/GlobalVariable.h b/include/llvm/IR/GlobalVariable.h index bf1e89181ea..112a8468e32 100644 --- a/include/llvm/IR/GlobalVariable.h +++ b/include/llvm/IR/GlobalVariable.h @@ -110,7 +110,10 @@ public: return hasInitializer() && // The initializer of a global variable with weak linkage may change at // link time. - !mayBeOverridden(); + !mayBeOverridden() && + // The initializer of a global variable with the externally_initialized + // marker may change at runtime before cxx initializers are evaluated. + !isExternallyInitialized(); } /// hasUniqueInitializer - Whether the global variable has an initializer, and @@ -123,7 +126,11 @@ public: // instead. It is wrong to modify the initializer of a global variable // with *_odr linkage because then different instances of the global may // have different initializers, breaking the One Definition Rule. - !isWeakForLinker(); + !isWeakForLinker() && + // It is not safe to modify initializers of global variables with the + // external_initializer marker since the value may be changed at runtime + // before cxx initializers are evaluated. + !isExternallyInitialized(); } /// getInitializer - Return the initializer for this global variable. It is diff --git a/test/Transforms/GlobalOpt/externally-initialized-global-ctr.ll b/test/Transforms/GlobalOpt/externally-initialized-global-ctr.ll new file mode 100644 index 00000000000..f447fe62873 --- /dev/null +++ b/test/Transforms/GlobalOpt/externally-initialized-global-ctr.ll @@ -0,0 +1,35 @@ +; RUN: opt < %s -globalopt -S | FileCheck %s +; rdar://12580965. +; ObjC++ test case. + +%struct.ButtonInitData = type { i8* } + +@_ZL14buttonInitData = internal global [1 x %struct.ButtonInitData] zeroinitializer, align 4 + +@"\01L_OBJC_METH_VAR_NAME_40" = internal global [7 x i8] c"print:\00", section "__TEXT,__objc_methname,cstring_literals", align 1 +@"\01L_OBJC_SELECTOR_REFERENCES_41" = internal externally_initialized global i8* getelementptr inbounds ([7 x i8]* @"\01L_OBJC_METH_VAR_NAME_40", i32 0, i32 0), section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip" + +@llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32, void ()* } { i32 65535, void ()* @_GLOBAL__I_a }] +@llvm.used = appending global [2 x i8*] [i8* getelementptr inbounds ([7 x i8]* @"\01L_OBJC_METH_VAR_NAME_40", i32 0, i32 0), i8* bitcast (i8** @"\01L_OBJC_SELECTOR_REFERENCES_41" to i8*)] + +define internal void @__cxx_global_var_init() section "__TEXT,__StaticInit,regular,pure_instructions" { + %1 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_41", !invariant.load !2009 + store i8* %1, i8** getelementptr inbounds ([1 x %struct.ButtonInitData]* @_ZL14buttonInitData, i32 0, i32 0, i32 0), align 4 + ret void +} + +define internal void @_GLOBAL__I_a() section "__TEXT,__StaticInit,regular,pure_instructions" { + call void @__cxx_global_var_init() + ret void +} + +declare void @test(i8*) + +define void @print() { +; CHECK: %1 = load i8** getelementptr inbounds ([1 x %struct.ButtonInitData]* @_ZL14buttonInitData, i32 0, i32 0, i32 0), align 4 + %1 = load i8** getelementptr inbounds ([1 x %struct.ButtonInitData]* @_ZL14buttonInitData, i32 0, i32 0, i32 0), align 4 + call void @test(i8* %1) + ret void +} + +!2009 = metadata !{} \ No newline at end of file -- 2.34.1