[clang] [Hexagon] Add sanitizer-aware library paths for Linux/musl targets (PR #190267)

[Alexey Karyakin via cfe-commits]

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@@ -600,6 +608,34 @@ HexagonToolChain::HexagonToolChain(const Driver &D, const llvm::Triple &Triple,
   // support 'linux' we'll need to fix this up
   LibPaths.clear();
   getHexagonLibraryPaths(Args, LibPaths);
+
+  if (getTriple().isMusl()) {
+    Multilibs.push_back(Multilib());
+    Multilibs.push_back(MultilibBuilder("msan", {}, {})
+                            .flag("-fsanitize=memory")
+                            .makeMultilib());
+    Multilibs.push_back(MultilibBuilder("asan", {}, {})
+                            .flag("-fsanitize=address")
+                            .makeMultilib());
+
+    Multilib::flags_list Flags;
+    addMultilibFlag(getSanitizerArgs(Args).needsMsanRt(), "-fsanitize=memory",
+                    Flags);
+    addMultilibFlag(getSanitizerArgs(Args).needsAsanRt(), "-fsanitize=address",
+                    Flags);
+
+    if (Multilibs.select(D, Flags, SelectedMultilibs)) {
+      Multilib LastSelected = SelectedMultilibs.back();
+      SelectedMultilibs = {LastSelected};
+
+      if (!SelectedMultilibs.back().isDefault()) {
+        SmallString<128> SanLibPath(D.SysRoot);
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quic-akaryaki wrote:

I added `getEffectiveSysRoot()` in #188824. For a native linux toolchain, it could return "".

https://github.com/llvm/llvm-project/pull/190267