From d4a1ae3f5696cc4c3741282569951dce3678d318 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Fri, 29 Aug 2014 00:16:06 +0000 Subject: [PATCH] Better codegen support for DLL attributes being dropped after the first declaration (PR20792) For the following code: __declspec(dllimport) int f(int x); int user(int x) { return f(x); } int f(int x) { return 1; } Clang will drop the dllimport attribute in the AST, but CodeGen would have already put it on the LLVM::Function, and that would never get updated. (The same thing happens for global variables.) This makes Clang check dropped DLL attribute case each time the LLVM object is referenced. This isn't perfect, because we will still get it wrong if the function is never referenced by codegen after the attribute is dropped, but this handles the common cases and makes us not fail in the verifier. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216699 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/CodeGenModule.cpp | 8 ++++++++ test/CodeGen/dllimport.c | 21 +++++++++++++++++---- 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp index 1f0dd73e65..aaadbd4633 100644 --- a/lib/CodeGen/CodeGenModule.cpp +++ b/lib/CodeGen/CodeGenModule.cpp @@ -1449,6 +1449,10 @@ CodeGenModule::GetOrCreateLLVMFunction(StringRef MangledName, Entry->setLinkage(llvm::Function::ExternalLinkage); } + // Handle dropped DLL attributes. + if (D && !D->hasAttr() && !D->hasAttr()) + Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass); + if (Entry->getType()->getElementType() == Ty) return Entry; @@ -1614,6 +1618,10 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, Entry->setLinkage(llvm::Function::ExternalLinkage); } + // Handle dropped DLL attributes. + if (D && !D->hasAttr() && !D->hasAttr()) + Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass); + if (Entry->getType() == Ty) return Entry; diff --git a/test/CodeGen/dllimport.c b/test/CodeGen/dllimport.c index 6ed60ea1e2..0f592d00f5 100644 --- a/test/CodeGen/dllimport.c +++ b/test/CodeGen/dllimport.c @@ -44,12 +44,19 @@ __declspec(dllimport) extern int GlobalRedecl3; extern int GlobalRedecl3; // dllimport ignored USEVAR(GlobalRedecl3) +// Make sure this works even if the decl has been used before it's defined (PR20792). +// CHECK: @GlobalRedecl4 = common global i32 +__declspec(dllimport) extern int GlobalRedecl4; +USEVAR(GlobalRedecl4) + int GlobalRedecl4; // dllimport ignored + + // Redeclaration in local context. -// CHECK: @GlobalRedecl4 = external dllimport global i32 -__declspec(dllimport) int GlobalRedecl4; +// CHECK: @GlobalRedecl5 = external dllimport global i32 +__declspec(dllimport) int GlobalRedecl5; int functionScope() { - extern int GlobalRedecl4; // still dllimport - return GlobalRedecl4; + extern int GlobalRedecl5; // still dllimport + return GlobalRedecl5; } @@ -99,3 +106,9 @@ USE(redecl2) __declspec(dllimport) void redecl3(void); void redecl3(void) {} // dllimport ignored USE(redecl3) + +// Make sure this works even if the decl is used before it's defined (PR20792). +// CHECK-DAG: define void @redecl4() +__declspec(dllimport) void redecl4(void); +USE(redecl4) + void redecl4(void) {} // dllimport ignored -- 2.40.0