Teach LTOModule to emit linker flags for dllexported symbols, plus interface cleanup.

This change unifies how LTOModule and the backend obtain linker flags
for globals: via a new TargetLoweringObjectFile member function named
emitLinkerFlagsForGlobal. A new function LTOModule::getLinkerOpts() returns
the list of linker flags as a single concatenated string.

This change affects the C libLTO API: the function lto_module_get_*deplibs now
exposes an empty list, and lto_module_get_*linkeropts exposes a single element
which combines the contents of all observed flags. libLTO should never have
tried to parse the linker flags; it is the linker's job to do so. Because
linkers will need to be able to parse flags in regular object files, it
makes little sense for libLTO to have a redundant mechanism for doing so.

The new API is compatible with the old one. It is valid for a user to specify
multiple linker flags in a single pragma directive like this:

 #pragma comment(linker, "/defaultlib:foo /defaultlib:bar")

The previous implementation would not have exposed
either flag via lto_module_get_*deplibs (as the test in
TargetLoweringObjectFileCOFF::getDepLibFromLinkerOpt was case sensitive)
and would have exposed "/defaultlib:foo /defaultlib:bar" as a single flag via
lto_module_get_*linkeropts. This may have been a bug in the implementation,
but it does give us a chance to fix the interface.

Differential Revision: http://reviews.llvm.org/D10548

llvm-svn: 241010

2 files changed, 66 insertions, 65 deletions

diff --git a/llvm/test/CodeGen/X86/dllexport-x86_64.ll b/llvm/test/CodeGen/X86/dllexport-x86_64.ll
index 629a5572977..bb5e92f98c7 100644
--- a/llvm/test/CodeGen/X86/dllexport-x86_64.ll
+++ b/llvm/test/CodeGen/X86/dllexport-x86_64.ll
@@ -71,33 +71,33 @@ define weak_odr dllexport void @weak1() {
 @blob_alias = dllexport alias bitcast ([6 x i8]* @blob to i32 ()*)
 
 ; CHECK: .section .drectve
-; WIN32: " /EXPORT:Var1,DATA"
-; WIN32: " /EXPORT:Var2,DATA"
-; WIN32: " /EXPORT:Var3,DATA"
-; WIN32: " /EXPORT:WeakVar1,DATA"
-; WIN32: " /EXPORT:WeakVar2,DATA"
-; WIN32: " /EXPORT:f1"
-; WIN32: " /EXPORT:f2"
-; WIN32: " /EXPORT:lnk1"
-; WIN32: " /EXPORT:lnk2"
-; WIN32: " /EXPORT:weak1"
-; WIN32: " /EXPORT:alias"
-; WIN32: " /EXPORT:alias2"
-; WIN32: " /EXPORT:alias3"
-; WIN32: " /EXPORT:weak_alias"
-; WIN32: " /EXPORT:blob_alias"
-; MINGW: " -export:Var1,data"
-; MINGW: " -export:Var2,data"
-; MINGW: " -export:Var3,data"
-; MINGW: " -export:WeakVar1,data"
-; MINGW: " -export:WeakVar2,data"
-; MINGW: " -export:f1"
-; MINGW: " -export:f2"
-; MINGW: " -export:lnk1"
-; MINGW: " -export:lnk2"
-; MINGW: " -export:weak1"
-; MINGW: " -export:alias"
-; MINGW: " -export:alias2"
-; MINGW: " -export:alias3"
-; MINGW: " -export:weak_alias"
-; MINGW: " -export:blob_alias"
+; WIN32: /EXPORT:f1
+; WIN32-SAME: /EXPORT:f2
+; WIN32-SAME: /EXPORT:lnk1
+; WIN32-SAME: /EXPORT:lnk2
+; WIN32-SAME: /EXPORT:weak1
+; WIN32-SAME: /EXPORT:Var1,DATA
+; WIN32-SAME: /EXPORT:Var2,DATA
+; WIN32-SAME: /EXPORT:Var3,DATA
+; WIN32-SAME: /EXPORT:WeakVar1,DATA
+; WIN32-SAME: /EXPORT:WeakVar2,DATA
+; WIN32-SAME: /EXPORT:alias
+; WIN32-SAME: /EXPORT:alias2
+; WIN32-SAME: /EXPORT:alias3
+; WIN32-SAME: /EXPORT:weak_alias
+; WIN32-SAME: /EXPORT:blob_alias
+; MINGW: -export:f1
+; MINGW-SAME: -export:f2
+; MINGW-SAME: -export:lnk1
+; MINGW-SAME: -export:lnk2
+; MINGW-SAME: -export:weak1
+; MINGW-SAME: -export:Var1,data
+; MINGW-SAME: -export:Var2,data
+; MINGW-SAME: -export:Var3,data
+; MINGW-SAME: -export:WeakVar1,data
+; MINGW-SAME: -export:WeakVar2,data
+; MINGW-SAME: -export:alias
+; MINGW-SAME: -export:alias2
+; MINGW-SAME: -export:alias3
+; MINGW-SAME: -export:weak_alias
+; MINGW-SAME: -export:blob_alias"
diff --git a/llvm/test/CodeGen/X86/dllexport.ll b/llvm/test/CodeGen/X86/dllexport.ll
index 02a83ae7b19..915567de5bf 100644
--- a/llvm/test/CodeGen/X86/dllexport.ll
+++ b/llvm/test/CodeGen/X86/dllexport.ll
@@ -89,40 +89,41 @@ define weak_odr dllexport void @weak1() {
 @weak_alias = weak_odr dllexport alias void()* @f1
 
 ; CHECK: .section .drectve
-; CHECK-CL: " /EXPORT:_Var1,DATA"
-; CHECK-CL: " /EXPORT:_Var2,DATA"
-; CHECK-CL: " /EXPORT:_Var3,DATA"
-; CHECK-CL: " /EXPORT:_WeakVar1,DATA"
-; CHECK-CL: " /EXPORT:_WeakVar2,DATA"
-; CHECK-CL: " /EXPORT:_f1"
-; CHECK-CL: " /EXPORT:_f2"
 ; CHECK-CL-NOT: not_exported
-; CHECK-CL: " /EXPORT:_stdfun@0"
-; CHECK-CL: " /EXPORT:@fastfun@0"
-; CHECK-CL: " /EXPORT:_thisfun"
-; CHECK-CL: " /EXPORT:_lnk1"
-; CHECK-CL: " /EXPORT:_lnk2"
-; CHECK-CL: " /EXPORT:_weak1"
-; CHECK-CL: " /EXPORT:_alias"
-; CHECK-CL: " /EXPORT:_alias2"
-; CHECK-CL: " /EXPORT:_alias3"
-; CHECK-CL: " /EXPORT:_weak_alias"
-; CHECK-GCC: " -export:Var1,data"
-; CHECK-GCC: " -export:Var2,data"
-; CHECK-GCC: " -export:Var3,data"
-; CHECK-GCC: " -export:WeakVar1,data"
-; CHECK-GCC: " -export:WeakVar2,data"
-; CHECK-GCC: " -export:f1"
-; CHECK-GCC: " -export:f2"
+; CHECK-CL: /EXPORT:_f1
+; CHECK-CL-SAME: /EXPORT:_f2
+; CHECK-CL-SAME: /EXPORT:_stdfun@0
+; CHECK-CL-SAME: /EXPORT:@fastfun@0
+; CHECK-CL-SAME: /EXPORT:_thisfun
+; CHECK-CL-SAME: /EXPORT:_lnk1
+; CHECK-CL-SAME: /EXPORT:_lnk2
+; CHECK-CL-SAME: /EXPORT:_weak1
+; CHECK-CL-SAME: /EXPORT:_Var1,DATA
+; CHECK-CL-SAME: /EXPORT:_Var2,DATA
+; CHECK-CL-SAME: /EXPORT:_Var3,DATA
+; CHECK-CL-SAME: /EXPORT:_WeakVar1,DATA
+; CHECK-CL-SAME: /EXPORT:_WeakVar2,DATA
+; CHECK-CL-SAME: /EXPORT:_alias
+; CHECK-CL-SAME: /EXPORT:_alias2
+; CHECK-CL-SAME: /EXPORT:_alias3
+; CHECK-CL-SAME: /EXPORT:_weak_alias"
 ; CHECK-CL-NOT: not_exported
-; CHECK-GCC: " -export:stdfun@0"
-; CHECK-GCC: " -export:@fastfun@0"
-; CHECK-GCC: " -export:thisfun"
-; CHECK-GCC: " -export:lnk1"
-; CHECK-GCC: " -export:lnk2"
-; CHECK-GCC: " -export:weak1"
-; CHECK-GCC: " -export:alias"
-; CHECK-GCC: " -export:alias2"
-; CHECK-GCC: " -export:alias3"
-; CHECK-GCC: " -export:weak_alias"
-
+; CHECK-GCC-NOT: not_exported
+; CHECK-GCC: -export:f1
+; CHECK-GCC-SAME: -export:f2
+; CHECK-GCC-SAME: -export:stdfun@0
+; CHECK-GCC-SAME: -export:@fastfun@0
+; CHECK-GCC-SAME: -export:thisfun
+; CHECK-GCC-SAME: -export:lnk1
+; CHECK-GCC-SAME: -export:lnk2
+; CHECK-GCC-SAME: -export:weak1
+; CHECK-GCC-SAME: -export:Var1,data
+; CHECK-GCC-SAME: -export:Var2,data
+; CHECK-GCC-SAME: -export:Var3,data
+; CHECK-GCC-SAME: -export:WeakVar1,data
+; CHECK-GCC-SAME: -export:WeakVar2,data
+; CHECK-GCC-SAME: -export:alias
+; CHECK-GCC-SAME: -export:alias2
+; CHECK-GCC-SAME: -export:alias3
+; CHECK-GCC-SAME: -export:weak_alias"
+; CHECK-GCC-NOT: not_exported