[clang] Add necessary linker flags when -static-pie is enabled in BareMetal Toolchain (PR #147589)

[Fangrui Song via cfe-commits]

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@@ -599,11 +599,18 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   const Driver &D = getToolChain().getDriver();
   const llvm::Triple::ArchType Arch = TC.getArch();
   const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+  const bool IsStaticPIE = getStaticPIE(Args, TC);
 
   if (!D.SysRoot.empty())
     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
 
   CmdArgs.push_back("-Bstatic");
+  if (IsStaticPIE) {
+    CmdArgs.push_back("-pie");
+    CmdArgs.push_back("--no-dynamic-linker");
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MaskRay wrote:

`ld.bfd -pie a.o -o a` might have a default linker script like`/lib/ld64.so.1`. --no-dynamic-linker suppresses it.

In addition, the option used to have special implication in LLD before 994cea3f0a2d0caf4d66321ad5a06ab330144d89

For compatibility with both linkers, --no-dynamic-linker is recommended for driver -static-pie.

https://github.com/llvm/llvm-project/pull/147589