From d9d049a93c55624908e81cf3927b7905efeba05f Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 14 Apr 2009 06:27:57 +0000 Subject: set the linkage of an inline function according to its language rules. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69030 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/CodeGenModule.cpp | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) (limited to 'lib/CodeGen/CodeGenModule.cpp') diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp index 1dafd39b2c..adf5ac2e41 100644 --- a/lib/CodeGen/CodeGenModule.cpp +++ b/lib/CodeGen/CodeGenModule.cpp @@ -262,8 +262,32 @@ void CodeGenModule::SetGlobalValueAttributes(const Decl *D, } } else if (D->hasAttr() || D->hasAttr()) { GV->setLinkage(llvm::Function::WeakAnyLinkage); - } else if (Linkage == GVA_Inline || Linkage == GVA_ExternInline) { - GV->setLinkage(llvm::Function::WeakAnyLinkage); + } else if (Linkage == GVA_ExternInline) { + // "extern inline" always gets available_externally linkage, which is the + // strongest linkage type we can give an inline function: we don't have to + // codegen the definition at all, yet we know that it is "ODR". + GV->setLinkage(llvm::Function::AvailableExternallyLinkage); + } else if (Linkage == GVA_Inline) { + // The definition of inline changes based on the language. Note that we + // have already handled "static inline" above, with the GVA_Internal case. + if (Features.CPlusPlus) { + // In C++, the compiler has to emit a definition in every translation unit + // that references the function. We should use linkonce_odr because + // a) if all references in this translation unit are optimized away, we + // don't need to codegen it. b) if the function persists, it needs to be + // merged with other definitions. c) C++ has the ODR, so we know the + // definition is dependable. + GV->setLinkage(llvm::Function::LinkOnceODRLinkage); + } else if (Features.C99) { + // In C99 mode, 'inline' functions are guaranteed to have a strong + // definition somewhere else, so we can use available_externally linkage. + GV->setLinkage(llvm::Function::AvailableExternallyLinkage); + } else { + // In C89 mode, an 'inline' function may only occur in one translation + // unit in the program, but may be extern'd in others. Give it strong + // external linkage. + GV->setLinkage(llvm::Function::ExternalLinkage); + } } if (ForDefinition) { -- cgit v1.2.3-18-g5258