[PATCH] D112589: [lld-macho] If export_size is zero, export_off must be zero

[Jez Ng via Phabricator via llvm-commits]

int3 updated this revision to Diff 382744.
int3 edited the summary of this revision.
int3 added a comment.
This revision is now accepted and ready to land.

actual fix


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112589/new/

https://reviews.llvm.org/D112589

Files:
  lld/MachO/SyntheticSections.h
  lld/MachO/Writer.cpp
  lld/test/MachO/no-unneeded-dyld-info.s


Index: lld/test/MachO/no-unneeded-dyld-info.s
===================================================================
--- lld/test/MachO/no-unneeded-dyld-info.s
+++ lld/test/MachO/no-unneeded-dyld-info.s
@@ -1,6 +1,6 @@
 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
-# RUN: %lld -o %t %t.o
+# RUN: %lld -dylib -o %t %t.o
 # RUN: llvm-objdump --macho --all-headers %t | FileCheck %s
 
 # CHECK:                 cmd LC_DYLD_INFO_ONLY
@@ -13,7 +13,8 @@
 # CHECK-NEXT: weak_bind_size 0
 # CHECK-NEXT:  lazy_bind_off 0
 # CHECK-NEXT: lazy_bind_size 0
+# CHECK-NEXT: export_off     0
+# CHECK-NEXT: export_size    0
 
-.globl _main
-_main:
-  ret
+_not_exported:
+  .space 1
Index: lld/MachO/Writer.cpp
===================================================================
--- lld/MachO/Writer.cpp
+++ lld/MachO/Writer.cpp
@@ -968,7 +968,12 @@
 
   for (SyntheticSection *ssec : syntheticSections) {
     auto it = concatOutputSections.find({ssec->segname, ssec->name});
-    if (ssec->isNeeded()) {
+    // We add all LinkEdit sections here because we don't know if they are
+    // needed until their finalizeContents() methods get called later. While
+    // this means that we add some redundant sections to __LINKEDIT, there is
+    // is no redundancy in the output, as we do not emit section headers for
+    // any LinkEdit sections.
+    if (ssec->isNeeded() || ssec->segname == segment_names::linkEdit) {
       if (it == concatOutputSections.end()) {
         getOrCreateOutputSegment(ssec->segname)->addOutputSection(ssec);
       } else {
Index: lld/MachO/SyntheticSections.h
===================================================================
--- lld/MachO/SyntheticSections.h
+++ lld/MachO/SyntheticSections.h
@@ -345,6 +345,7 @@
   ExportSection();
   void finalizeContents() override;
   uint64_t getRawSize() const override { return size; }
+  bool isNeeded() const override { return size; }
   void writeTo(uint8_t *buf) const override;
 
   bool hasWeakSymbol = false;


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