llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-lld-coff Author: Alexandre Ganea (aganea) <details> <summary>Changes</summary> Backport https://github.com/llvm/llvm-project/pull/134443 on release/20.x: > This reverts commit 6a1bdd9 and re-instate behavior that matches what MSVC link.exe does, that is, error out when trying to dllimport a symbol from a static library. > > A hint is now displayed in stdout, mentioning that we should rather dllimport the symbol from a import library. > > Fixes https://github.com/llvm/llvm-project/issues/131807 --- Full diff: https://github.com/llvm/llvm-project/pull/138354.diff 6 Files Affected: - (modified) lld/COFF/Driver.cpp (+2-4) - (modified) lld/COFF/SymbolTable.cpp (+12-8) - (modified) lld/COFF/SymbolTable.h (+1-4) - (added) lld/test/COFF/imports-static-lib-indirect.test (+26) - (added) lld/test/COFF/imports-static-lib.test (+33) - (removed) lld/test/COFF/undefined_lazy.test (-26) ``````````diff diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp index ac3ac57bd17f4..f50ca529df4d7 100644 --- a/lld/COFF/Driver.cpp +++ b/lld/COFF/Driver.cpp @@ -2639,10 +2639,8 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) { createECExportThunks(); // Resolve remaining undefined symbols and warn about imported locals. - ctx.forEachSymtab([&](SymbolTable &symtab) { - while (symtab.resolveRemainingUndefines()) - run(); - }); + ctx.forEachSymtab( + [&](SymbolTable &symtab) { symtab.resolveRemainingUndefines(); }); if (errorCount()) return; diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp index 307bd4a0c9411..8448d47d505f6 100644 --- a/lld/COFF/SymbolTable.cpp +++ b/lld/COFF/SymbolTable.cpp @@ -232,6 +232,17 @@ static void reportUndefinedSymbol(COFFLinkerContext &ctx, } if (numDisplayedRefs < numRefs) diag << "\n>>> referenced " << numRefs - numDisplayedRefs << " more times"; + + // Hints + StringRef name = undefDiag.sym->getName(); + if (name.consume_front("__imp_")) { + Symbol *imp = find(name); + if (imp && imp->isLazy()) { + diag << "\nNOTE: a relevant symbol '" << imp->getName() + << "' is available in " << toString(imp->getFile()) + << " but cannot be used because it is not an import library."; + } + } } void SymbolTable::loadMinGWSymbols() { @@ -432,11 +443,10 @@ void SymbolTable::reportUnresolvable() { reportProblemSymbols(undefs, /*localImports=*/nullptr, true); } -bool SymbolTable::resolveRemainingUndefines() { +void 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; @@ -481,11 +491,6 @@ bool SymbolTable::resolveRemainingUndefines() { imp = findLocalSym(*mangledName); } } - 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); @@ -513,7 +518,6 @@ bool SymbolTable::resolveRemainingUndefines() { reportProblemSymbols( 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 ff6e8487f0734..2916c23d95c87 100644 --- a/lld/COFF/SymbolTable.h +++ b/lld/COFF/SymbolTable.h @@ -58,10 +58,7 @@ 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. - // 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(); + void resolveRemainingUndefines(); // Load lazy objects that are needed for MinGW automatic import and for // doing stdcall fixups. diff --git a/lld/test/COFF/imports-static-lib-indirect.test b/lld/test/COFF/imports-static-lib-indirect.test new file mode 100644 index 0000000000000..beda0d7a31afd --- /dev/null +++ b/lld/test/COFF/imports-static-lib-indirect.test @@ -0,0 +1,26 @@ +# REQUIRES: x86 + +# Pulling in on both a dllimport symbol and a static symbol should only warn. +# RUN: split-file %s %t.dir +# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/other.s -o %t.other.obj +# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/main.s -o %t.main.obj +# RUN: llvm-lib %t.other.obj -out:%t.other.lib +# RUN: lld-link %t.other.lib %t.main.obj -out:%t.dll -dll 2>&1 | FileCheck %s + +CHECK: warning: {{.*}} locally defined symbol imported: foo {{.*}} [LNK4217] + +#--- other.s +.text +.globl other +.globl foo +other: + ret +foo: + ret +#--- main.s +.text +.global _DllMainCRTStartup +_DllMainCRTStartup: + call *other(%rip) + call *__imp_foo(%rip) + ret diff --git a/lld/test/COFF/imports-static-lib.test b/lld/test/COFF/imports-static-lib.test new file mode 100644 index 0000000000000..8e9525dab5284 --- /dev/null +++ b/lld/test/COFF/imports-static-lib.test @@ -0,0 +1,33 @@ +# REQUIRES: x86 + +# Ensure that we don't import dllimport symbols from static (non-import) libraries +# RUN: split-file %s %t.dir +# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/foo.s -o %t.foo.obj +# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/main.s -o %t.main.obj +# RUN: llvm-lib %t.foo.obj -out:%t.foo.lib +# RUN: not lld-link %t.foo.lib %t.main.obj -out:%t.dll -dll 2>&1 | FileCheck %s + +CHECK: error: undefined symbol: __declspec(dllimport) foo +CHECK: NOTE: a relevant symbol 'foo' is available in {{.*}}.foo.lib but cannot be used because it is not an import library. + +# Now do the same thing, but import the symbol from a import library. +# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/foo_dll_main.s -o %t.foo_dll_main.obj +# RUN: lld-link /out:%t.dll /dll %t.foo.obj %t.foo_dll_main.obj /export:foo /implib:%t.foo.imp.lib +# RUN: lld-link %t.main.obj %t.foo.imp.lib -out:%t.exe -dll + +#--- foo.s +.text +.globl foo +foo: + ret +#--- foo_dll_main.s +.text +.global _DllMainCRTStartup +_DllMainCRTStartup: + ret +#--- main.s +.text +.global _DllMainCRTStartup +_DllMainCRTStartup: + call *__imp_foo(%rip) + ret diff --git a/lld/test/COFF/undefined_lazy.test b/lld/test/COFF/undefined_lazy.test deleted file mode 100644 index ed5cd358b5cd9..0000000000000 --- a/lld/test/COFF/undefined_lazy.test +++ /dev/null @@ -1,26 +0,0 @@ -# REQUIRES: x86 - -# RUN: split-file %s %t.dir -# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/foo.s -o %t.foo.obj -# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/bar.s -o %t.bar.obj -# RUN: llvm-mc --filetype=obj -triple=x86_64-windows-msvc %t.dir/qux.s -o %t.qux.obj -# RUN: llvm-lib %t.foo.obj -out:%t.foo.lib -# RUN: llvm-lib %t.bar.obj -out:%t.bar.lib -# RUN: lld-link %t.foo.lib %t.bar.lib %t.qux.obj -out:%t.dll -dll -# -#--- foo.s -.text -.globl foo -foo: - call bar -#--- bar.s -.text -.globl bar -bar: - ret -#--- qux.s -.text -.global _DllMainCRTStartup -_DllMainCRTStartup: - call *__imp_foo(%rip) - ret `````````` </details> https://github.com/llvm/llvm-project/pull/138354 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
