From 809f5c72b6dbfdae5bda51cc68218c716f2eedf9 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Sun, 22 May 2016 01:37:36 +0000
Subject: [PATCH] Driver: simplify getDynameLinker

Convert the cascading if/else to a switch.  This makes it easier to follow the
logic.  Minor difference is that we no longer default to x86_64 but rather to
the architecture specified by the architecture.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@270351 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/Tools.cpp | 96 ++++++++++++++++++++++----------------------
 1 file changed, 49 insertions(+), 47 deletions(-)

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 8a1cb541c1..2eee8b8fbc 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -8989,66 +8989,68 @@ static std::string getLinuxDynamicLinker(const ArgList &Args,
   const llvm::Triple::ArchType Arch = ToolChain.getArch();
   const llvm::Triple &Triple = ToolChain.getTriple();
 
-  if (Triple.isAndroid()) {
-    if (Triple.isArch64Bit())
-      return "/system/bin/linker64";
-    else
-      return "/system/bin/linker";
-  } else if (Arch == llvm::Triple::x86 || Arch == llvm::Triple::sparc ||
-             Arch == llvm::Triple::sparcel)
-    return "/lib/ld-linux.so.2";
-  else if (Arch == llvm::Triple::aarch64)
+  if (Triple.isAndroid())
+    return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
+
+  switch (Arch) {
+  default: llvm_unreachable("unsupported architecture");
+
+  case llvm::Triple::aarch64:
     return "/lib/ld-linux-aarch64.so.1";
-  else if (Arch == llvm::Triple::aarch64_be)
+  case llvm::Triple::aarch64_be:
     return "/lib/ld-linux-aarch64_be.so.1";
-  else if (Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb) {
-    if (Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
-        arm::getARMFloatABI(ToolChain, Args) == arm::FloatABI::Hard)
-      return "/lib/ld-linux-armhf.so.3";
-    else
-      return "/lib/ld-linux.so.3";
-  } else if (Arch == llvm::Triple::armeb || Arch == llvm::Triple::thumbeb) {
-    // TODO: check which dynamic linker name.
-    if (Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
-        arm::getARMFloatABI(ToolChain, Args) == arm::FloatABI::Hard)
-      return "/lib/ld-linux-armhf.so.3";
-    else
-      return "/lib/ld-linux.so.3";
-  } else if (Arch == llvm::Triple::mips || Arch == llvm::Triple::mipsel ||
-             Arch == llvm::Triple::mips64 || Arch == llvm::Triple::mips64el) {
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumbeb: {
+    const bool IsHardFloat =
+        Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
+        arm::getARMFloatABI(ToolChain, Args) == arm::FloatABI::Hard;
+
+    return IsHardFloat ? "/lib/ld-linux-armhf.so.3" : "/lib/ld-linux.so.3";
+  }
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el: {
+    bool IsNaN2008 = mips::isNaN2008(Args, Triple);
+    bool LE = (Triple.getArch() == llvm::Triple::mipsel) ||
+              (Triple.getArch() == llvm::Triple::mips64el);
+
     std::string LibDir = "/lib" + mips::getMipsABILibSuffix(Args, Triple);
     StringRef LibName;
-    bool IsNaN2008 = mips::isNaN2008(Args, Triple);
     if (mips::isUCLibc(Args))
       LibName = IsNaN2008 ? "ld-uClibc-mipsn8.so.0" : "ld-uClibc.so.0";
     else if (!Triple.hasEnvironment() &&
-             Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies) {
-      bool LE = (Triple.getArch() == llvm::Triple::mipsel) ||
-                (Triple.getArch() == llvm::Triple::mips64el);
+             Triple.getVendor() == llvm::Triple::VendorType::MipsTechnologies)
       LibName = LE ? "ld-musl-mipsel.so.1" : "ld-musl-mips.so.1";
-    } else
+    else
       LibName = IsNaN2008 ? "ld-linux-mipsn8.so.1" : "ld.so.1";
 
     return (LibDir + "/" + LibName).str();
-  } else if (Arch == llvm::Triple::ppc)
+  }
+  case llvm::Triple::ppc:
     return "/lib/ld.so.1";
-  else if (Arch == llvm::Triple::ppc64) {
-    if (ppc::hasPPCAbiArg(Args, "elfv2"))
-      return "/lib64/ld64.so.2";
-    return "/lib64/ld64.so.1";
-  } else if (Arch == llvm::Triple::ppc64le) {
-    if (ppc::hasPPCAbiArg(Args, "elfv1"))
-      return "/lib64/ld64.so.1";
-    return "/lib64/ld64.so.2";
-  } else if (Arch == llvm::Triple::systemz)
-    return "/lib/ld64.so.1";
-  else if (Arch == llvm::Triple::sparcv9)
+  case llvm::Triple::ppc64:
+    return (ppc::hasPPCAbiArg(Args, "elfv2")) ? "/lib64/ld64.so.2"
+                                              : "/lib64/ld64.so.1";
+  case llvm::Triple::ppc64le:
+    return (ppc::hasPPCAbiArg(Args, "elfv1")) ? "/lib64/ld64.so.1"
+                                              : "/lib64/ld64.so.2";
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+    return "/lib/ld-linux.so.2";
+  case llvm::Triple::sparcv9:
     return "/lib64/ld-linux.so.2";
-  else if (Arch == llvm::Triple::x86_64 &&
-           Triple.getEnvironment() == llvm::Triple::GNUX32)
-    return "/libx32/ld-linux-x32.so.2";
-  else
-    return "/lib64/ld-linux-x86-64.so.2";
+  case llvm::Triple::systemz:
+    return "/lib/ld64.so.1";
+  case llvm::Triple::x86:
+    return "/lib/ld-linux.so.2";
+  case llvm::Triple::x86_64:
+    return (Triple.getEnvironment() == llvm::Triple::GNUX32)
+               ? "/libx32/ld-linux-x32.so.2"
+               : "/lib64/ld-linux-x86-64.so.2";
+  }
 }
 
 static void AddRunTimeLibs(const ToolChain &TC, const Driver &D,
-- 
2.40.0