[Driver] -rdynamic: remove duplicate -export-dynamic

-export-dynamic is specified twice when -static is not specified. Fix
it.

While here, make some simplification, which can match GCC behavior as a
side benefit: suppress -export-dynamic for -static-pie/-shared. (GCC
passes -export-dynamic when -r is specified. This is unimportant
trivia).

This change largely has no behavior difference, since GNU ld and gold
ignore -export-dynamic when creating a statically linked executable or a
shared object.

Author: MaskRay

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -417,9 +417,6 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("text");
   }
 
-  if (Args.hasArg(options::OPT_rdynamic))
-    CmdArgs.push_back("-export-dynamic");
-
   if (Args.hasArg(options::OPT_s))
     CmdArgs.push_back("-s");
 
@@ -459,16 +456,14 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   if (IsStatic) {
     CmdArgs.push_back("-static");
-  } else {
+  } else if (!Args.hasArg(options::OPT_r) &&
+             !Args.hasArg(options::OPT_shared) && !IsStaticPIE) {
     if (Args.hasArg(options::OPT_rdynamic))
       CmdArgs.push_back("-export-dynamic");
 
-    if (!Args.hasArg(options::OPT_shared) && !IsStaticPIE &&
-        !Args.hasArg(options::OPT_r)) {
-      CmdArgs.push_back("-dynamic-linker");
-      CmdArgs.push_back(Args.MakeArgString(Twine(D.DyldPrefix) +
-                                           ToolChain.getDynamicLinker(Args)));
-    }
+    CmdArgs.push_back("-dynamic-linker");
+    CmdArgs.push_back(Args.MakeArgString(Twine(D.DyldPrefix) +
+                                         ToolChain.getDynamicLinker(Args)));
   }
 
   CmdArgs.push_back("-o");

clang/test/Driver/dynamic-linker.c

@@ -11,20 +11,20 @@
 // RUN: %clang -target x86_64-unknown-linux-gnu -### -shared /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
 
 
-// RUN: %clang -target armv7-unknown-linux-gnueabi -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED -check-prefix CHECK-RDYNAMIC %s
-// RUN: %clang -target i386-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED -check-prefix CHECK-RDYNAMIC %s
-// RUN: %clang -target mips64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED -check-prefix CHECK-RDYNAMIC %s
-// RUN: %clang -target powerpc64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED -check-prefix CHECK-RDYNAMIC %s
-// RUN: %clang -target x86_64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED -check-prefix CHECK-RDYNAMIC %s
+// RUN: %clang -target armv7-unknown-linux-gnueabi -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
+// RUN: %clang -target i386-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
+// RUN: %clang -target mips64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
+// RUN: %clang -target powerpc64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
+// RUN: %clang -target x86_64-unknown-linux-gnu -### -shared -rdynamic /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-SHARED %s
 
 // RUN: %clang -target armv7-unknown-linux-gnueabi -### -static /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-STATIC %s
 // RUN: %clang -target i386-unknown-linux-gnu -### -static /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-STATIC %s
 // RUN: %clang -target mips64-unknown-linux-gnu -### -static /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-STATIC %s
 // RUN: %clang -target powerpc64-unknown-linux-gnu -### -static /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-STATIC %s
 // RUN: %clang -target x86_64-unknown-linux-gnu -### -static /dev/null -o /dev/null 2>&1 | FileCheck -check-prefix CHECK-STATIC %s
 
-// CHECK-RDYNAMIC: "-export-dynamic"
 // CHECK-SHARED: "-shared"
+// CHECK-RDYNAMIC: "-export-dynamic"
 // CHECK-STATIC: "-{{B?}}static"
 // CHECK-DYNAMIC-LINKER: "-dynamic-linker"
 // CHECK-SHARED-NOT: "-dynamic-linker"