[lld] [LLD][COFF] Rebuild nodefaultlibs after updating search paths and support /noexp (PR #128808)

[via llvm-commits]

https://github.com/A2uria created https://github.com/llvm/llvm-project/pull/128808

Fix #107346

>From e3f21d4781b22666652da342ef514777e472f2ed Mon Sep 17 00:00:00 2001
From: A2uria <a2uria at qq.com>
Date: Wed, 26 Feb 2025 11:16:52 +0800
Subject: [PATCH 1/2] [LLD][COFF] Add /noexp for link.exe compatibility

---
 lld/COFF/Options.td | 1 +
 1 file changed, 1 insertion(+)

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">;

>From ff02813799d7d9e1cff0826ed1162c901ace9a2a Mon Sep 17 00:00:00 2001
From: A2uria <a2uria at qq.com>
Date: Wed, 26 Feb 2025 11:23:14 +0800
Subject: [PATCH 2/2] [LLD][COFF] Rebuild nodefaultlibs after updating search
 paths

Fix #107346
---
 lld/COFF/Driver.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

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.