[lld-macho] -section_rename should work on synthetic sections too

Previously, we only applied the renames to
ConcatOutputSections.

Reviewed By: #lld-macho, thakis

Differential Revision: https://reviews.llvm.org/D105079

Author: int3

lld/MachO/SyntheticSections.cpp

@@ -47,7 +47,8 @@ InStruct macho::in;
 std::vector<SyntheticSection *> macho::syntheticSections;
 
 SyntheticSection::SyntheticSection(const char *segname, const char *name)
-    : OutputSection(SyntheticKind, name), segname(segname) {
+    : OutputSection(SyntheticKind, name) {
+  std::tie(this->segname, this->name) = maybeRenameSection({segname, name});
   isec = make<ConcatInputSection>(segname, name);
   isec->parent = this;
   syntheticSections.push_back(this);

lld/MachO/SyntheticSections.h

@@ -46,7 +46,7 @@ class SyntheticSection : public OutputSection {
     return sec->kind() == SyntheticKind;
   }
 
-  const StringRef segname;
+  StringRef segname;
   // This fake InputSection makes it easier for us to write code that applies
   // generically to both user inputs and synthetics.
   InputSection *isec;

lld/MachO/Writer.cpp

@@ -855,7 +855,7 @@ static void sortSegmentsAndSections() {
   }
 }
 
-static NamePair maybeRenameSection(NamePair key) {
+NamePair macho::maybeRenameSection(NamePair key) {
   auto newNames = config->sectionRenameMap.find(key);
   if (newNames != config->sectionRenameMap.end())
     return newNames->second;

lld/MachO/Writer.h

@@ -9,6 +9,8 @@
 #ifndef LLD_MACHO_WRITER_H
 #define LLD_MACHO_WRITER_H
 
+#include "Config.h"
+
 #include <cstdint>
 
 namespace lld {
@@ -27,6 +29,8 @@ class LoadCommand {
 
 template <class LP> void writeResult();
 
+NamePair maybeRenameSection(NamePair key);
+
 void createSyntheticSections();
 
 // Add bindings for symbols that need weak or non-lazy bindings.

lld/test/MachO/rename.s

@@ -30,21 +30,22 @@
 # RUN: %lld \
 # RUN:     -rename_section __FROM_SECT __from_sect __TO_SECT __to_sect \
 # RUN:     -rename_segment __FROM_SEG __TO_SEG \
+# RUN:     -rename_section __TEXT __cstring __RODATA __cstring \
 # RUN:   -o %t %t.o
 # RUN: llvm-objdump --macho --all-headers %t | FileCheck %s
 
 # CHECK:      {{^}}Section{{$}}
 # CHECK-NEXT: sectname __text
 # CHECK-NEXT: segname __TEXT
 # CHECK:      {{^}}Section{{$}}
-# CHECK-NOT:  sectname __from_sect
 # CHECK-NEXT: sectname __to_sect
-# CHECK-NOT:  segname __FROM_SECT
 # CHECK-NEXT: segname __TO_SECT
 # CHECK:      {{^}}Section{{$}}
 # CHECK-NEXT: sectname __from_seg
-# CHECK-NOT:  segname __FROM_SEG
 # CHECK-NEXT: segname __TO_SEG
+# CHECK:      {{^}}Section{{$}}
+# CHECK-NEXT: sectname __cstring
+# CHECK-NEXT: segname __RODATA
 
 .section __FROM_SECT,__from_sect
 .global _from_sect
@@ -56,6 +57,10 @@ _from_sect:
 _from_seg:
   .space 8
 
+## This is a synthetic section; make sure it gets renamed too.
+.cstring
+  .space 8
+
 .text
 .global _main
 _main: