[lld] [LLD][COFF] Do another pass of resolveRemainingUndefines for undefined lazy symbols (PR #109082)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lld

Author: Mike Hommey (glandium)

<details>
<summary>Changes</summary>

Cc: @<!-- -->mstorsjo 

This addresses #<!-- -->107365 except for the strdup part.

---
Full diff: https://github.com/llvm/llvm-project/pull/109082.diff


3 Files Affected:

- (modified) lld/COFF/Driver.cpp (+4-1) 
- (modified) lld/COFF/SymbolTable.cpp (+8-1) 
- (modified) lld/COFF/SymbolTable.h (+4-1) 


``````````diff
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 1b94f10acf80e5..38a507cb9752ff 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -2601,7 +2601,10 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
     createECExportThunks();
 
   // Resolve remaining undefined symbols and warn about imported locals.
-  ctx.symtab.resolveRemainingUndefines();
+  if (ctx.symtab.resolveRemainingUndefines()) {
+    run();
+    ctx.symtab.resolveRemainingUndefines();
+  }
   if (errorCount())
     return;
 
diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp
index efea16ccbbfea0..8d69a3966e638f 100644
--- a/lld/COFF/SymbolTable.cpp
+++ b/lld/COFF/SymbolTable.cpp
@@ -479,10 +479,11 @@ void SymbolTable::reportUnresolvable() {
                        /* localImports */ nullptr, true);
 }
 
-void SymbolTable::resolveRemainingUndefines() {
+bool SymbolTable::resolveRemainingUndefines() {
   llvm::TimeTraceScope timeScope("Resolve remaining undefined symbols");
   SmallPtrSet<Symbol *, 8> undefs;
   DenseMap<Symbol *, Symbol *> localImports;
+  bool foundLazy = false;
 
   for (auto &i : symMap) {
     Symbol *sym = i.second;
@@ -502,6 +503,11 @@ void SymbolTable::resolveRemainingUndefines() {
     // This odd rule is for compatibility with MSVC linker.
     if (name.starts_with("__imp_")) {
       Symbol *imp = find(name.substr(strlen("__imp_")));
+      if (imp && imp->isLazy()) {
+        forceLazy(imp);
+        foundLazy = true;
+        continue;
+      }
       if (imp && isa<Defined>(imp)) {
         auto *d = cast<Defined>(imp);
         replaceSymbol<DefinedLocalImport>(sym, ctx, name, d);
@@ -529,6 +535,7 @@ void SymbolTable::resolveRemainingUndefines() {
   reportProblemSymbols(
       ctx, undefs,
       ctx.config.warnLocallyDefinedImported ? &localImports : nullptr, false);
+  return foundLazy;
 }
 
 std::pair<Symbol *, bool> SymbolTable::insert(StringRef name) {
diff --git a/lld/COFF/SymbolTable.h b/lld/COFF/SymbolTable.h
index bf97cf442039e0..1ab35a87cb9fad 100644
--- a/lld/COFF/SymbolTable.h
+++ b/lld/COFF/SymbolTable.h
@@ -57,7 +57,10 @@ class SymbolTable {
   // Try to resolve any undefined symbols and update the symbol table
   // accordingly, then print an error message for any remaining undefined
   // symbols and warn about imported local symbols.
-  void resolveRemainingUndefines();
+  // Returns whether more files might need to be linked in to resolve lazy
+  // symbols, in which case the caller is expected to call the function again
+  // after linking those files.
+  bool resolveRemainingUndefines();
 
   // Load lazy objects that are needed for MinGW automatic import and for
   // doing stdcall fixups.

``````````

</details>


https://github.com/llvm/llvm-project/pull/109082