[LLD][COFF] Rebuild nodefaultlibs after updating search paths and support /noexp

[A2uria]

Fix #107346

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[llvmbot]

@llvm/pr-subscribers-platform-windows
@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-coff

Author: None (A2uria)

Changes

Fix #107346

---

Full diff: https://github.com/llvm/llvm-project/pull/128808.diff

2 Files Affected:

• (modified) lld/COFF/Driver.cpp (+7)
• (modified) lld/COFF/Options.td (+1)

diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 1589323073c09..086ec83cc5206 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -786,6 +786,13 @@ void LinkerDriver::addWinSysRootLibSearchPaths() {
                                       path))
       searchPaths.push_back(saver().save(path));
   }
+
+  // Libraries specified by `/nodefaultlib:` may not be found in incomplete
+  // search paths before lld infers a machine type from input files.
+  std::set<std::string> noDefaultLibs;
+  for (const std::string &path : ctx.config.noDefaultLibs)
+    noDefaultLibs.insert(findLib(path).lower());
+  ctx.config.noDefaultLibs = noDefaultLibs;
 }
 
 // Parses LIB environment which contains a list of search paths.
diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
index b6fd3d0daaef9..4e401a5fd1d6d 100644
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -342,6 +342,7 @@ def fastfail : F<"fastfail">;
 def kernel : F<"kernel">;
 def pdbcompress : F<"pdbcompress">;
 def emitpogophaseinfo : F<"emitpogophaseinfo">;
+def noexp : F<"noexp">;
 
 def delay : P_priv<"delay">;
 def errorreport : P_priv<"errorreport">;

[A2uria]

Not sure about "this branch must not contain merge commits", split into #128813 and #128814