[AIX]: Fix option processing for -b

Code added by D106688 has a problem. It passes the option -bxyz to the system linker as -b xyz xyz (duplication of the string 'xyz' is incorrect). This patch fixes that oversight.

Reviewed by: hubert.reinterpretcast, jsji

Differential Revision: https://reviews.llvm.org/D107786

Author: Ettore Tiotto

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -257,16 +257,6 @@ void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
     // Otherwise, this is a linker input argument.
     const Arg &A = II.getInputArg();
 
-    if (A.getOption().matches(options::OPT_b)) {
-      const llvm::Triple &T = TC.getTriple();
-      if (!T.isOSAIX()) {
-        TC.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
-          << A.getSpelling() << T.str();
-      }
-      // Pass -b prefix for AIX linker.
-      A.claim();
-      A.render(Args, CmdArgs);
-    }
     // Handle reserved library options.
     if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx))
       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
@@ -276,6 +266,15 @@ void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
       // Pass -z prefix for gcc linker compatibility.
       A.claim();
       A.render(Args, CmdArgs);
+    } else if (A.getOption().matches(options::OPT_b)) {
+      const llvm::Triple &T = TC.getTriple();
+      if (!T.isOSAIX()) {
+        TC.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
+            << A.getSpelling() << T.str();
+      }
+      // Pass -b prefix for AIX linker.
+      A.claim();
+      A.render(Args, CmdArgs);
     } else {
       A.renderAsInput(Args, CmdArgs);
     }

clang/test/Driver/Xlinker-args.c

@@ -13,7 +13,7 @@
 // RUN: FileCheck -check-prefix=LINUX < %t %s
 
 // RUN: %clang -target powerpc-unknown-aix -### \
-// RUN:   -b one %s 2> %t
+// RUN:   -b one -b two %s 2> %t
 // RUN: FileCheck -check-prefix=AIX < %t %s
 
 // RUN: %clang -target powerpc-unknown-linux -### \
@@ -23,7 +23,7 @@
 // DARWIN-NOT: --no-demangle
 // DARWIN: "one" "two" "three" "four" "-z" "five" "-r"
 // LINUX: "--no-demangle" "-e" "_start" "one" "two" "three" "four" "-z" "five" "-r" {{.*}} "-T" "a.lds"
-// AIX: "-b" "one" 
+// AIX: "-b" "one" "-b" "two"
 // NOT-AIX: error: unsupported option '-b' for target 'powerpc-unknown-linux'
 
 // Check that we forward '-Xlinker' and '-Wl,' on Windows.