[LLD][COFF] Use EC symbol table for output DEF file on ARM64X

[cjacek]

For consistency with input def handling.

[cjacek]

Since this is a MinGW extension, we define its meaning. Other command-line arguments apply either to the EC symbol table or both, so for consistency, we should use the EC symbol table.

For the input DEF file, a new command-line option, -defarm64native, specifies the native symbol table instead. We could introduce a similar option for the output DEF file, but I’m not sure it’s necessary. My suggestion is to skip it for now and add it later if there’s demand.

[llvmbot]

@llvm/pr-subscribers-lld-coff
@llvm/pr-subscribers-lld

@llvm/pr-subscribers-platform-windows

Author: Jacek Caban (cjacek)

Changes

For consistency with input def handling.

---

Full diff: https://github.com/llvm/llvm-project/pull/125531.diff

2 Files Affected:

• (modified) lld/COFF/Driver.cpp (+1-1)
• (modified) lld/test/COFF/arm64x-export.test (+5-1)

diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index b848e0d81dfa76..979c0ae4962732 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -2692,7 +2692,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
 
   // Handle /output-def (MinGW specific).
   if (auto *arg = args.getLastArg(OPT_output_def))
-    writeDefFile(ctx, arg->getValue(), ctx.symtab.exports);
+    writeDefFile(ctx, arg->getValue(), mainSymtab.exports);
 
   // Set extra alignment for .comm symbols
   for (auto pair : config->alignComm) {
diff --git a/lld/test/COFF/arm64x-export.test b/lld/test/COFF/arm64x-export.test
index bae40af4585ae1..c83db2a436db50 100644
--- a/lld/test/COFF/arm64x-export.test
+++ b/lld/test/COFF/arm64x-export.test
@@ -14,7 +14,7 @@ RUN: llvm-mc -filetype=obj -triple=aarch64-windows %S/Inputs/loadconfig-arm64.s
 # A command-line export applies only to EC exports.
 
 RUN: lld-link -machine:arm64x -dll -out:out-cmd.dll arm64ec-func.obj arm64-func.obj \
-RUN:          loadconfig-arm64.obj loadconfig-arm64ec.obj -noentry -export:func
+RUN:          loadconfig-arm64.obj loadconfig-arm64ec.obj -noentry -export:func -output-def:out.def
 
 RUN: llvm-objdump -d out-cmd.dll | FileCheck --check-prefix=DISASM-EC %s
 DISASM-EC:      Disassembly of section .text:
@@ -74,6 +74,10 @@ IMPLIB-EC-NEXT: Symbol: func
 IMPLIB-EC-NEXT: Symbol: __imp_aux_func
 IMPLIB-EC-NEXT: Symbol: #func
 
+RUN: FileCheck --check-prefix=OUT-DEF %s < out.def
+OUT-DEF:      EXPORTS
+OUT-DEF-NEXT:     func @1
+
 
 # Export using the EC .drectve section.
 

[mstorsjo]

Sounds reasonable overall; yes, let's not invent new options until we have a known case where we'd need it, and until we have it all settled how we otherwise want things to behave in a mingw context.

The code looks good, but I've got one question on the testcase.

[mstorsjo]

LGTM