[Driver] Make ELF -nopie specific to OpenBSD (llvm#72578)

-no-pie[1]/-nopie is rarely used and among the rare uses almost
everwhere uses -no-pie, since GCC does not recognize -nopie.
However, OpenBSD seems to use -nopie. Therefore, make -nopie specific
to OpenBSD to prevent newer ToolChains (Solaris, SerenityOS) from cargo
culting and copying -nopie.

[1]: https://reviews.llvm.org/D35462

Author: MaskRay

clang/include/clang/Driver/Options.td

@@ -5158,7 +5158,7 @@ def nofixprebinding : Flag<["-"], "nofixprebinding">;
 def nolibc : Flag<["-"], "nolibc">;
 def nomultidefs : Flag<["-"], "nomultidefs">;
 def nopie : Flag<["-"], "nopie">, Visibility<[ClangOption, FlangOption]>;
-def no_pie : Flag<["-"], "no-pie">, Visibility<[ClangOption, FlangOption]>, Alias<nopie>;
+def no_pie : Flag<["-"], "no-pie">, Visibility<[ClangOption, FlangOption]>;
 def noprebind : Flag<["-"], "noprebind">;
 def noprofilelib : Flag<["-"], "noprofilelib">;
 def noseglinkedit : Flag<["-"], "noseglinkedit">;

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -294,9 +294,7 @@ static const char *getLDMOption(const llvm::Triple &T, const ArgList &Args) {
 
 static bool getStaticPIE(const ArgList &Args, const ToolChain &TC) {
   bool HasStaticPIE = Args.hasArg(options::OPT_static_pie);
-  // -no-pie is an alias for -nopie. So, handling -nopie takes care of
-  // -no-pie as well.
-  if (HasStaticPIE && Args.hasArg(options::OPT_nopie)) {
+  if (HasStaticPIE && Args.hasArg(options::OPT_no_pie)) {
     const Driver &D = TC.getDriver();
     const llvm::opt::OptTable &Opts = D.getOpts();
     StringRef StaticPIEName = Opts.getOptionName(options::OPT_static_pie);
@@ -443,10 +441,8 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     if (Args.hasArg(options::OPT_rdynamic))
       CmdArgs.push_back("-export-dynamic");
     if (!IsShared) {
-      Arg *A = Args.getLastArg(options::OPT_pie, options::OPT_no_pie,
-                               options::OPT_nopie);
-      IsPIE = A ? A->getOption().matches(options::OPT_pie)
-                : ToolChain.isPIEDefault(Args);
+      IsPIE = Args.hasFlag(options::OPT_pie, options::OPT_no_pie,
+                           ToolChain.isPIEDefault(Args));
       if (IsPIE)
         CmdArgs.push_back("-pie");
       CmdArgs.push_back("-dynamic-linker");

clang/lib/Driver/ToolChains/OpenBSD.cpp

@@ -116,7 +116,7 @@ void openbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   const bool Shared = Args.hasArg(options::OPT_shared);
   const bool Profiling = Args.hasArg(options::OPT_pg);
   const bool Pie = Args.hasArg(options::OPT_pie);
-  const bool Nopie = Args.hasArg(options::OPT_nopie);
+  const bool Nopie = Args.hasArg(options::OPT_no_pie, options::OPT_nopie);
   const bool Relocatable = Args.hasArg(options::OPT_r);
   ArgStringList CmdArgs;
 

clang/lib/Driver/ToolChains/Solaris.cpp

@@ -49,11 +49,8 @@ static bool getPIE(const ArgList &Args, const ToolChain &TC) {
       Args.hasArg(options::OPT_r))
     return false;
 
-  Arg *A = Args.getLastArg(options::OPT_pie, options::OPT_no_pie,
-                           options::OPT_nopie);
-  if (!A)
-    return TC.isPIEDefault(Args);
-  return A->getOption().matches(options::OPT_pie);
+  return Args.hasFlag(options::OPT_pie, options::OPT_no_pie,
+                      TC.isPIEDefault(Args));
 }
 
 // FIXME: Need to handle CLANG_DEFAULT_LINKER here?

clang/test/Driver/android-pie.c

@@ -36,8 +36,6 @@
 
 // RUN: %clang %s -### -o %t.o 2>&1 -no-pie --target=arm-linux-androideabi24 \
 // RUN:   | FileCheck --check-prefix=NO-PIE %s
-// RUN: %clang %s -### -o %t.o 2>&1 -nopie --target=arm-linux-androideabi24 \
-// RUN:   | FileCheck --check-prefix=NO-PIE %s
 // RUN: %clang %s -### -o %t.o 2>&1 -pie -no-pie --target=arm-linux-androideabi24 \
 // RUN:   | FileCheck --check-prefix=NO-PIE %s
 

clang/test/Driver/pic.c

@@ -166,11 +166,11 @@
 // RUN:   | FileCheck %s --check-prefix=CHECK-PIE2
 // RUN: %clang -c %s -target armv7-linux-musleabihf -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-PIE2
-// RUN: %clang %s -target x86_64-linux-musl -nopie -### 2>&1 \
+// RUN: %clang %s --target=x86_64-linux-musl -no-pie -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIE
-// RUN: %clang %s -target x86_64-linux-musl -pie -nopie -### 2>&1 \
+// RUN: %clang %s --target=x86_64-linux-musl -pie -no-pie -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIE
-// RUN: %clang %s -target x86_64-linux-musl -nopie -pie -### 2>&1 \
+// RUN: %clang %s --target=x86_64-linux-musl -no-pie -pie -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-PIE2
 //
 // Darwin is a beautiful and unique snowflake when it comes to these flags.