[Hexagon] Make lld be the default linker for linux/musl

When the target is hexagon-unknown-linux-musl select lld as the default
linker.

Differential Revision: https://reviews.llvm.org/D77498

Author: SidManning

clang/lib/Driver/ToolChains/Hexagon.h

@@ -81,7 +81,9 @@ class LLVM_LIBRARY_VISIBILITY HexagonToolChain : public Linux {
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
-  const char *getDefaultLinker() const override { return "hexagon-link"; }
+  const char *getDefaultLinker() const override {
+    return getTriple().isMusl() ? "ld.lld" : "hexagon-link";
+  }
 
   CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
 

clang/test/Driver/hexagon-toolchain-elf.c

@@ -674,3 +674,15 @@
 // RUN:   | FileCheck -check-prefix=CHECK090 %s
 // CHECK090-NOT:          -fno-use-init-array
 // -----------------------------------------------------------------------------
+// Check default linker for musl
+// -----------------------------------------------------------------------------
+// RUN: %clang -### -target hexagon-unknown-linux-musl %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK091 %s
+// CHECK091:          ld.lld
+// -----------------------------------------------------------------------------
+// Check default linker for elf
+// -----------------------------------------------------------------------------
+// RUN: %clang -### -target hexagon-unknown-elf %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK092 %s
+// CHECK092:          hexagon-link
+// -----------------------------------------------------------------------------