ARM: support export directives for Windows

It seems that cl will emit the export directives for Windows ARM targets.  The
fact that it did this had originally been missed and this functionality was
never implemented.  This makes it possible to rely solely on the source code for
indicating what the exported interfaces are and brings us more compatibility
with cl.

llvm-svn: 269574

2 files changed, 98 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
index 6d0608f9baa..8e064714108 100644
--- a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -548,6 +548,29 @@ void ARMAsmPrinter::EmitEndOfAsmFile(Module &M) {
     OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
   }
 
+  if (TT.isOSBinFormatCOFF()) {
+    const auto &TLOF =
+        static_cast<const TargetLoweringObjectFileCOFF &>(getObjFileLowering());
+
+    std::string Flags;
+    raw_string_ostream OS(Flags);
+
+    for (const auto &Function : M)
+      TLOF.emitLinkerFlagsForGlobal(OS, &Function, *Mang);
+    for (const auto &Global : M.globals())
+      TLOF.emitLinkerFlagsForGlobal(OS, &Global, *Mang);
+    for (const auto &Alias : M.aliases())
+      TLOF.emitLinkerFlagsForGlobal(OS, &Alias, *Mang);
+
+    OS.flush();
+
+    // Output collected flags
+    if (!Flags.empty()) {
+      OutStreamer->SwitchSection(TLOF.getDrectveSection());
+      OutStreamer->EmitBytes(Flags);
+    }
+  }
+
   // The last attribute to be emitted is ABI_optimization_goals
   MCTargetStreamer &TS = *OutStreamer->getTargetStreamer();
   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
diff --git a/llvm/test/CodeGen/ARM/Windows/dllexport.ll b/llvm/test/CodeGen/ARM/Windows/dllexport.ll
new file mode 100644
index 00000000000..27496208862
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/Windows/dllexport.ll
@@ -0,0 +1,75 @@
+; RUN: llc -mtriple thumbv7--windows-itanium -filetype asm -o - %s | FileCheck %s -check-prefix CHECK -check-prefix CHECK-GNU
+; RUN: llc -mtriple thumbv7--windows-gnu -filetype asm -o - %s | FileCheck %s -check-prefix CHECK -check-prefix CHECK-GNU
+; RUN: llc -mtriple thumbv7--windows-msvc -filetype asm -o - %s | FileCheck %s -check-prefix CHECK -check-prefix CHECK-MSVC
+
+define void @f() {
+  ret void
+}
+
+define dllexport void @g() {
+  ret void
+}
+
+define dllexport void @h() unnamed_addr {
+  ret void
+}
+
+declare dllexport void @i()
+
+define linkonce_odr dllexport void @j() {
+  ret void
+}
+
+define linkonce_odr dllexport void @k() alwaysinline {
+  ret void
+}
+
+define weak_odr dllexport void @l() {
+  ret void
+}
+
+@m = dllexport global i32 0, align 4
+@n = dllexport unnamed_addr constant i32 0
+@o = common dllexport global i32 0, align 4
+@p = weak_odr dllexport global i32 0, align 4
+@q = weak_odr dllexport unnamed_addr constant i32 0
+
+@r = dllexport alias void (), void () * @f
+@s = dllexport alias void (), void () * @g
+@t = dllexport alias void (), void () * @f
+@u = weak_odr dllexport alias void (), void () * @g
+
+; CHECK: .section .drectve
+; CHECK-GNU-NOT: -export:f
+; CHECK-GNU: -export:g
+; CHECK-GNU-SAME: -export:h
+; CHECK-GNU-NOT: -export:i
+; CHECK-GNU-SAME: -export:j
+; CHECK-GNU-SAME: -export:k
+; CHECK-GNU-SAME: -export:l
+; CHECK-GNU-SAME: -export:m,data
+; CHECK-GNU-SAME: -export:n,data
+; CHECK-GNU-SAME: -export:o,data
+; CHECK-GNU-SAME: -export:p,data
+; CHECK-GNU-SAME: -export:q,data
+; CHECK-GNU-SAME: -export:r
+; CHECK-GNU-SAME: -export:s
+; CHECK-GNU-SAME: -export:t
+; CHECK-GNU-SAME: -export:u
+; CHECK-MSVC-NOT: /EXPORT:f
+; CHECK-MSVC: /EXPORT:g
+; CHECK-MSVC-SAME: /EXPORT:h
+; CHECK-MSVC-NOT: /EXPORT:i
+; CHECK-MSVC-SAME: /EXPORT:j
+; CHECK-MSVC-SAME: /EXPORT:k
+; CHECK-MSVC-SAME: /EXPORT:l
+; CHECK-MSVC-SAME: /EXPORT:m,DATA
+; CHECK-MSVC-SAME: /EXPORT:n,DATA
+; CHECK-MSVC-SAME: /EXPORT:o,DATA
+; CHECK-MSVC-SAME: /EXPORT:p,DATA
+; CHECK-MSVC-SAME: /EXPORT:q,DATA
+; CHECK-MSVC-SAME: /EXPORT:r
+; CHECK-MSVC-SAME: /EXPORT:s
+; CHECK-MSVC-SAME: /EXPORT:t
+; CHECK-MSVC-SAME: /EXPORT:u
+