[LLD][COFF] Add support for autoimports on ARM64X

[cjacek]

No description provided.

[llvmbot]

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

@llvm/pr-subscribers-lld

Author: Jacek Caban (cjacek)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/129282.diff

3 Files Affected:

• (modified) lld/COFF/Driver.cpp (+1-1)
• (modified) lld/COFF/Writer.cpp (+42-38)
• (added) lld/test/COFF/autoimport-arm64x-data.test (+75)

diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 1589323073c09..f7addc29d1a3a 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -2600,7 +2600,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
     // If it ends up pulling in more object files from static libraries,
     // (and maybe doing more stdcall fixups along the way), this would need
     // to loop these two calls.
-    ctx.symtab.loadMinGWSymbols();
+    ctx.forEachSymtab([](SymbolTable &symtab) { symtab.loadMinGWSymbols(); });
     run();
   }
 
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index 0a84bce146483..a8148446a2657 100644
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -2288,49 +2288,53 @@ void Writer::createECChunks() {
 // uses for fixing them up, and provide the synthetic symbols that the
 // runtime uses for finding the table.
 void Writer::createRuntimePseudoRelocs() {
-  std::vector<RuntimePseudoReloc> rels;
+  ctx.forEachSymtab([&](SymbolTable &symtab) {
+    std::vector<RuntimePseudoReloc> rels;
 
-  for (Chunk *c : ctx.driver.getChunks()) {
-    auto *sc = dyn_cast<SectionChunk>(c);
-    if (!sc || !sc->live)
-      continue;
-    // Don't create pseudo relocations for sections that won't be
-    // mapped at runtime.
-    if (sc->header->Characteristics & IMAGE_SCN_MEM_DISCARDABLE)
-      continue;
-    sc->getRuntimePseudoRelocs(rels);
-  }
+    for (Chunk *c : ctx.driver.getChunks()) {
+      auto *sc = dyn_cast<SectionChunk>(c);
+      if (!sc || !sc->live || &sc->file->symtab != &symtab)
+        continue;
+      // Don't create pseudo relocations for sections that won't be
+      // mapped at runtime.
+      if (sc->header->Characteristics & IMAGE_SCN_MEM_DISCARDABLE)
+        continue;
+      sc->getRuntimePseudoRelocs(rels);
+    }
 
-  if (!ctx.config.pseudoRelocs) {
-    // Not writing any pseudo relocs; if some were needed, error out and
-    // indicate what required them.
-    for (const RuntimePseudoReloc &rpr : rels)
-      Err(ctx) << "automatic dllimport of " << rpr.sym->getName() << " in "
-               << toString(rpr.target->file) << " requires pseudo relocations";
-    return;
-  }
+    if (!ctx.config.pseudoRelocs) {
+      // Not writing any pseudo relocs; if some were needed, error out and
+      // indicate what required them.
+      for (const RuntimePseudoReloc &rpr : rels)
+        Err(ctx) << "automatic dllimport of " << rpr.sym->getName() << " in "
+                 << toString(rpr.target->file)
+                 << " requires pseudo relocations";
+      return;
+    }
 
-  if (!rels.empty()) {
-    Log(ctx) << "Writing " << rels.size() << " runtime pseudo relocations";
-    const char *symbolName = "_pei386_runtime_relocator";
-    Symbol *relocator = ctx.symtab.findUnderscore(symbolName);
-    if (!relocator)
-      Err(ctx)
-          << "output image has runtime pseudo relocations, but the function "
-          << symbolName
-          << " is missing; it is needed for fixing the relocations at runtime";
-  }
+    if (!rels.empty()) {
+      Log(ctx) << "Writing " << Twine(rels.size())
+               << " runtime pseudo relocations";
+      const char *symbolName = "_pei386_runtime_relocator";
+      Symbol *relocator = symtab.findUnderscore(symbolName);
+      if (!relocator)
+        Err(ctx)
+            << "output image has runtime pseudo relocations, but the function "
+            << symbolName
+            << " is missing; it is needed for fixing the relocations at "
+               "runtime";
+    }
 
-  PseudoRelocTableChunk *table = make<PseudoRelocTableChunk>(rels);
-  rdataSec->addChunk(table);
-  EmptyChunk *endOfList = make<EmptyChunk>();
-  rdataSec->addChunk(endOfList);
+    PseudoRelocTableChunk *table = make<PseudoRelocTableChunk>(rels);
+    rdataSec->addChunk(table);
+    EmptyChunk *endOfList = make<EmptyChunk>();
+    rdataSec->addChunk(endOfList);
 
-  Symbol *headSym = ctx.symtab.findUnderscore("__RUNTIME_PSEUDO_RELOC_LIST__");
-  Symbol *endSym =
-      ctx.symtab.findUnderscore("__RUNTIME_PSEUDO_RELOC_LIST_END__");
-  replaceSymbol<DefinedSynthetic>(headSym, headSym->getName(), table);
-  replaceSymbol<DefinedSynthetic>(endSym, endSym->getName(), endOfList);
+    Symbol *headSym = symtab.findUnderscore("__RUNTIME_PSEUDO_RELOC_LIST__");
+    Symbol *endSym = symtab.findUnderscore("__RUNTIME_PSEUDO_RELOC_LIST_END__");
+    replaceSymbol<DefinedSynthetic>(headSym, headSym->getName(), table);
+    replaceSymbol<DefinedSynthetic>(endSym, endSym->getName(), endOfList);
+  });
 }
 
 // MinGW specific.
diff --git a/lld/test/COFF/autoimport-arm64x-data.test b/lld/test/COFF/autoimport-arm64x-data.test
new file mode 100644
index 0000000000000..c0636b900a264
--- /dev/null
+++ b/lld/test/COFF/autoimport-arm64x-data.test
@@ -0,0 +1,75 @@
+# REQUIRES: aarch64
+RUN: split-file %s %t.dir && cd %t.dir
+
+RUN: llvm-lib -machine:arm64x -out:libtest.a -defArm64Native:test.def -def:test.def
+RUN: llvm-mc -triple=arm64ec-windows-gnu arm64ec.s -filetype=obj -o arm64ec.obj
+RUN: llvm-mc -triple=aarch64-windows-gnu aarch64.s -filetype=obj -o aarch64.obj
+RUN: llvm-mc -filetype=obj -triple=arm64ec-windows %S/Inputs/loadconfig-arm64ec.s -o loadconfig-arm64ec.obj
+RUN: llvm-mc -filetype=obj -triple=aarch64-windows %S/Inputs/loadconfig-arm64.s -o loadconfig-arm64.obj
+
+RUN: lld-link -machine:arm64x -out:out.dll -dll -noentry arm64ec.obj aarch64.obj libtest.a loadconfig-arm64.obj loadconfig-arm64ec.obj -lldmingw
+
+RUN: llvm-readobj --coff-imports out.dll | FileCheck -check-prefix=IMPORTS %s
+RUN: llvm-objdump -s out.dll | FileCheck --check-prefix=CONTENTS %s
+
+IMPORTS:      Import {
+IMPORTS-NEXT:   Name: test.dll
+IMPORTS-NEXT:   ImportLookupTableRVA: 0x5{{.*}}
+IMPORTS-NEXT:   ImportAddressTableRVA: 0x4000
+IMPORTS-NEXT:   Symbol: variable (0)
+IMPORTS-NEXT: }
+IMPORTS-NEXT: HybridObject {
+IMPORTS:        Import {
+IMPORTS-NEXT:     Name: test.dll
+IMPORTS-NEXT:     ImportLookupTableRVA: 0x5{{.*}}
+IMPORTS-NEXT:     ImportAddressTableRVA: 0x4000
+IMPORTS-NEXT:     Symbol: variable (0)
+IMPORTS-NEXT:   }
+IMPORTS-NEXT: }
+
+Native ARM64 runtime pseudo relocation list header at 0x5164, consisting of 0x0, 0x0, 0x1.
+The runtime pseudo relocation is from an aarch64.obj object file, with import from 0x4000,
+applied at 0x9018 with a size of 32 bits. ARM64EC runtime pseudo relocation list header at
+0x517c, consisting of 0x0, 0x0, 0x1. The runtime pseudo relocation is from arm64ec.obj
+object file, with import from 0x4000, applied at 0x9000 with a size of 32 bits.
+
+CONTENTS: Contents of section .rdata:
+CONTENTS:  180005160 00300000 00000000 00000000 01000000
+CONTENTS:  180005170 00400000 18900000 40000000 00000000
+CONTENTS:  180005180 00000000 01000000 00400000 00900000
+CONTENTS:  180005190 40000000
+
+CONTENTS:      Contents of section .test:
+CONTENTS-NEXT:  180009000 00400080 01000000 7c510080 01000000
+CONTENTS-NEXT:  180009010 94510080 01000000 00400080 01000000
+CONTENTS-NEXT:  180009020 64510080 01000000 7c510080 01000000
+
+#--- arm64ec.s
+    .text
+    .global "#_pei386_runtime_relocator"
+"#_pei386_runtime_relocator":
+    ret
+
+    .weak_anti_dep _pei386_runtime_relocator
+.set _pei386_runtime_relocator,"#_pei386_runtime_relocator"
+
+    .section .test,"dr"
+    .quad variable
+    .quad __RUNTIME_PSEUDO_RELOC_LIST__
+    .quad __RUNTIME_PSEUDO_RELOC_LIST_END__
+
+#--- aarch64.s
+    .text
+    .global _pei386_runtime_relocator
+_pei386_runtime_relocator:
+    ret
+
+    .section .test,"dr"
+    .quad variable
+    .quad __RUNTIME_PSEUDO_RELOC_LIST__
+    .quad __RUNTIME_PSEUDO_RELOC_LIST_END__
+
+#--- test.def
+LIBRARY test.dll
+EXPORTS
+    variable DATA

[mstorsjo]

LGTM, thanks! Although there's a couple details in the test comments that I'm unsure about.

[mstorsjo]

Is the size really 32 bit? 32 bit pseudo relocations in 64 bit images usually is a problem (and we warn about them nowadays too); as the reference is a .quad I presume that it is 64 bit?

[cjacek]

Yes, it's 64 bit, good catch, thanks! I copied it from arm64ec test, which was based on aarch64 version, I will create a separate PR to fix those.

[mstorsjo]

Ditto