[lld] [LLD][COFF] Preserve all attributes from forwarding exports from parsed .def files. (PR #86564)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lld-coff

Author: Jacek Caban (cjacek)

<details>
<summary>Changes</summary>

This depends on #<!-- -->86535.

It similar to #<!-- -->86535, but for export specified in .def files.

---
Full diff: https://github.com/llvm/llvm-project/pull/86564.diff


3 Files Affected:

- (modified) lld/COFF/Driver.cpp (+7-8) 
- (modified) lld/COFF/DriverUtils.cpp (+6-7) 
- (modified) lld/test/COFF/export.test (+40-3) 


``````````diff
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 1b075389325a91..181492913c0d98 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1032,19 +1032,18 @@ void LinkerDriver::parseModuleDefs(StringRef path) {
 
   for (COFFShortExport e1 : m.Exports) {
     Export e2;
-    // In simple cases, only Name is set. Renamed exports are parsed
-    // and set as "ExtName = Name". If Name has the form "OtherDll.Func",
-    // it shouldn't be a normal exported function but a forward to another
-    // DLL instead. This is supported by both MS and GNU linkers.
+    // Renamed exports are parsed and set as "ExtName = Name". If Name has
+    // the form "OtherDll.Func", it shouldn't be a normal exported
+    // function but a forward to another DLL instead. This is supported
+    // by both MS and GNU linkers.
     if (!e1.ExtName.empty() && e1.ExtName != e1.Name &&
         StringRef(e1.Name).contains('.')) {
       e2.name = saver().save(e1.ExtName);
       e2.forwardTo = saver().save(e1.Name);
-      ctx.config.exports.push_back(e2);
-      continue;
+    } else {
+      e2.name = saver().save(e1.Name);
+      e2.extName = saver().save(e1.ExtName);
     }
-    e2.name = saver().save(e1.Name);
-    e2.extName = saver().save(e1.ExtName);
     e2.aliasTarget = saver().save(e1.AliasTarget);
     e2.ordinal = e1.Ordinal;
     e2.noname = e1.Noname;
diff --git a/lld/COFF/DriverUtils.cpp b/lld/COFF/DriverUtils.cpp
index fc8eb327be49bd..0fa4769bab19db 100644
--- a/lld/COFF/DriverUtils.cpp
+++ b/lld/COFF/DriverUtils.cpp
@@ -577,16 +577,15 @@ Export LinkerDriver::parseExport(StringRef arg) {
     if (y.contains(".")) {
       e.name = x;
       e.forwardTo = y;
-      return e;
+    } else {
+      e.extName = x;
+      e.name = y;
+      if (e.name.empty())
+        goto err;
     }
-
-    e.extName = x;
-    e.name = y;
-    if (e.name.empty())
-      goto err;
   }
 
-  // If "<name>=<internalname>[, at ordinal[,NONAME]][,DATA][,PRIVATE]"
+  // Optional parameters "[, at ordinal[,NONAME]][,DATA][,PRIVATE]"
   while (!rest.empty()) {
     StringRef tok;
     std::tie(tok, rest) = rest.split(",");
diff --git a/lld/test/COFF/export.test b/lld/test/COFF/export.test
index d340e0174b563e..49577704e6897f 100644
--- a/lld/test/COFF/export.test
+++ b/lld/test/COFF/export.test
@@ -76,18 +76,55 @@ SYMTAB: exportfn3 in export.test.tmp.DLL
 
 # RUN: lld-link /out:%t.dll /dll %t.obj /export:foo=kernel32.foobar
 # RUN: llvm-objdump -p %t.dll | FileCheck --check-prefix=FORWARDER %s
+# RUN: llvm-nm -M %t.lib | FileCheck --check-prefix=SYMTAB-FWD %s
 
 # RUN: echo "EXPORTS foo=kernel32.foobar" > %t.def
-# RUN: lld-link /out:%t.dll /dll %t.obj /def:%t.def
-# RUN: llvm-objdump -p %t.dll | FileCheck --check-prefix=FORWARDER %s
+# RUN: lld-link /out:%t-def.dll /dll %t.obj /def:%t.def
+# RUN: llvm-objdump -p %t-def.dll | FileCheck --check-prefix=FORWARDER %s
+# RUN: llvm-nm -M %t-def.lib | FileCheck --check-prefix=SYMTAB-FWD %s
 
 FORWARDER: Export Table:
-FORWARDER:  DLL name: export.test.tmp.dll
+FORWARDER:  DLL name: export.test.tmp
 FORWARDER:  Ordinal base: 1
 FORWARDER:  Ordinal      RVA  Name
 FORWARDER:        1   0x1010  exportfn
 FORWARDER:        2           foo (forwarded to kernel32.foobar)
 
+SYMTAB-FWD: __imp_exportfn3 in export.test.tmp
+SYMTAB-FWD: __imp_foo in export.test.tmp
+SYMTAB-FWD: exportfn3 in export.test.tmp
+SYMTAB-FWD: foo in export.test.tmp
+
+# RUN: lld-link /out:%t-fwd-priv.dll /dll %t.obj /export:foo=kernel32.foobar,DATA,PRIVATE
+# RUN: llvm-objdump -p %t-fwd-priv.dll | FileCheck --check-prefix=FORWARDER %s
+# RUN: llvm-nm -M %t-fwd-priv.lib | FileCheck --check-prefix=SYMTAB-FWD-PRIV %s
+
+SYMTAB-FWD-PRIV:     __imp_exportfn3 in export.test.tmp-fwd-priv
+SYMTAB-FWD-PRIV-NOT: __imp_foo
+SYMTAB-FWD-PRIV:     exportfn3 in export.test.tmp-fwd-priv
+SYMTAB-FWD-PRIV-NOT: foo
+
+# RUN: echo "EXPORTS foo=kernel32.foobar DATA PRIVATE" > %t-fwd-priv.def
+# RUN: lld-link /out:%t-fwd-priv-def.dll /dll %t.obj /def:%t-fwd-priv.def
+# RUN: llvm-objdump -p %t-fwd-priv-def.dll | FileCheck --check-prefix=FORWARDER %s
+# RUN: llvm-nm -M %t-fwd-priv-def.lib | FileCheck --check-prefix=SYMTAB-FWD-PRIV %s
+
+# RUN: lld-link /out:%t-fwd-ord.dll /dll %t.obj /export:foo=kernel32.foobar, at 3,NONAME
+# RUN: llvm-objdump -p %t-fwd-ord.dll | FileCheck --check-prefix=FORWARDER-ORD %s
+# RUN: llvm-nm -M %t-fwd-ord.lib | FileCheck --check-prefix=SYMTAB-FWD %s
+
+FORWARDER-ORD: Export Table:
+FORWARDER-ORD:  DLL name: export.test.tmp-fwd-ord
+FORWARDER-ORD:  Ordinal base: 3
+FORWARDER-ORD:  Ordinal      RVA  Name
+FORWARDER-ORD:        3           (forwarded to kernel32.foobar)
+FORWARDER-ORD:        4   0x1010  exportfn3
+
+# RUN: echo "EXPORTS foo=kernel32.foobar @3 NONAME" > %t-fwd-ord.def
+# RUN: lld-link /out:%t-fwd-ord-def.dll /dll %t.obj /def:%t-fwd-ord.def
+# RUN: llvm-objdump -p %t-fwd-ord-def.dll | FileCheck --check-prefix=FORWARDER-ORD %s
+# RUN: llvm-nm -M %t-fwd-ord-def.lib | FileCheck --check-prefix=SYMTAB-FWD %s
+
 # RUN: lld-link /out:%t.dll /dll %t.obj /merge:.rdata=.text /export:exportfn1 /export:exportfn2
 # RUN: llvm-objdump -p %t.dll | FileCheck --check-prefix=MERGE --match-full-lines %s
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/86564