[lld] 648157b - [ELF] Move getOutputSectionName from Writer.cpp to LinkerScript.cpp. NFC

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2021-11-20T22:18:09-08:00
New Revision: 648157b05a1d5d17e03515e4858ccc70155f8c4e

URL: https://github.com/llvm/llvm-project/commit/648157b05a1d5d17e03515e4858ccc70155f8c4e
DIFF: https://github.com/llvm/llvm-project/commit/648157b05a1d5d17e03515e4858ccc70155f8c4e.diff

LOG: [ELF] Move getOutputSectionName from Writer.cpp to LinkerScript.cpp. NFC

and internalize it.

Added: 
    

Modified: 
    lld/ELF/LinkerScript.cpp
    lld/ELF/Writer.cpp
    lld/ELF/Writer.h

Removed: 
    


################################################################################
diff  --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index f332b03d757df..6657f21af6758 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -49,12 +49,73 @@ using namespace lld::elf;
 
 LinkerScript *elf::script;
 
+static bool isSectionPrefix(StringRef prefix, StringRef name) {
+  return name.startswith(prefix) || name == prefix.drop_back();
+}
+
 static uint64_t getOutputSectionVA(SectionBase *sec) {
   OutputSection *os = sec->getOutputSection();
   assert(os && "input section has no output section assigned");
   return os ? os->addr : 0;
 }
 
+static StringRef getOutputSectionName(const InputSectionBase *s) {
+  if (config->relocatable)
+    return s->name;
+
+  // This is for --emit-relocs. If .text.foo is emitted as .text.bar, we want
+  // to emit .rela.text.foo as .rela.text.bar for consistency (this is not
+  // technically required, but not doing it is odd). This code guarantees that.
+  if (auto *isec = dyn_cast<InputSection>(s)) {
+    if (InputSectionBase *rel = isec->getRelocatedSection()) {
+      OutputSection *out = rel->getOutputSection();
+      if (s->type == SHT_RELA)
+        return saver.save(".rela" + out->name);
+      return saver.save(".rel" + out->name);
+    }
+  }
+
+  // A BssSection created for a common symbol is identified as "COMMON" in
+  // linker scripts. It should go to .bss section.
+  if (s->name == "COMMON")
+    return ".bss";
+
+  if (script->hasSectionsCommand)
+    return s->name;
+
+  // When no SECTIONS is specified, emulate GNU ld's internal linker scripts
+  // by grouping sections with certain prefixes.
+
+  // GNU ld places text sections with prefix ".text.hot.", ".text.unknown.",
+  // ".text.unlikely.", ".text.startup." or ".text.exit." before others.
+  // We provide an option -z keep-text-section-prefix to group such sections
+  // into separate output sections. This is more flexible. See also
+  // sortISDBySectionOrder().
+  // ".text.unknown" means the hotness of the section is unknown. When
+  // SampleFDO is used, if a function doesn't have sample, it could be very
+  // cold or it could be a new function never being sampled. Those functions
+  // will be kept in the ".text.unknown" section.
+  // ".text.split." holds symbols which are split out from functions in other
+  // input sections. For example, with -fsplit-machine-functions, placing the
+  // cold parts in .text.split instead of .text.unlikely mitigates against poor
+  // profile inaccuracy. Techniques such as hugepage remapping can make
+  // conservative decisions at the section granularity.
+  if (config->zKeepTextSectionPrefix)
+    for (StringRef v : {".text.hot.", ".text.unknown.", ".text.unlikely.",
+                        ".text.startup.", ".text.exit.", ".text.split."})
+      if (isSectionPrefix(v, s->name))
+        return v.drop_back();
+
+  for (StringRef v :
+       {".text.", ".rodata.", ".data.rel.ro.", ".data.", ".bss.rel.ro.",
+        ".bss.", ".init_array.", ".fini_array.", ".ctors.", ".dtors.", ".tbss.",
+        ".gcc_except_table.", ".tdata.", ".ARM.exidx.", ".ARM.extab."})
+    if (isSectionPrefix(v, s->name))
+      return v.drop_back();
+
+  return s->name;
+}
+
 uint64_t ExprValue::getValue() const {
   if (sec)
     return alignTo(sec->getOffset(val) + getOutputSectionVA(sec),

diff  --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 6d97852aec434..1137825a4322c 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -91,67 +91,6 @@ template <class ELFT> class Writer {
 };
 } // anonymous namespace
 
-static bool isSectionPrefix(StringRef prefix, StringRef name) {
-  return name.startswith(prefix) || name == prefix.drop_back();
-}
-
-StringRef elf::getOutputSectionName(const InputSectionBase *s) {
-  if (config->relocatable)
-    return s->name;
-
-  // This is for --emit-relocs. If .text.foo is emitted as .text.bar, we want
-  // to emit .rela.text.foo as .rela.text.bar for consistency (this is not
-  // technically required, but not doing it is odd). This code guarantees that.
-  if (auto *isec = dyn_cast<InputSection>(s)) {
-    if (InputSectionBase *rel = isec->getRelocatedSection()) {
-      OutputSection *out = rel->getOutputSection();
-      if (s->type == SHT_RELA)
-        return saver.save(".rela" + out->name);
-      return saver.save(".rel" + out->name);
-    }
-  }
-
-  // A BssSection created for a common symbol is identified as "COMMON" in
-  // linker scripts. It should go to .bss section.
-  if (s->name == "COMMON")
-    return ".bss";
-
-  if (script->hasSectionsCommand)
-    return s->name;
-
-  // When no SECTIONS is specified, emulate GNU ld's internal linker scripts
-  // by grouping sections with certain prefixes.
-
-  // GNU ld places text sections with prefix ".text.hot.", ".text.unknown.",
-  // ".text.unlikely.", ".text.startup." or ".text.exit." before others.
-  // We provide an option -z keep-text-section-prefix to group such sections
-  // into separate output sections. This is more flexible. See also
-  // sortISDBySectionOrder().
-  // ".text.unknown" means the hotness of the section is unknown. When
-  // SampleFDO is used, if a function doesn't have sample, it could be very
-  // cold or it could be a new function never being sampled. Those functions
-  // will be kept in the ".text.unknown" section.
-  // ".text.split." holds symbols which are split out from functions in other
-  // input sections. For example, with -fsplit-machine-functions, placing the
-  // cold parts in .text.split instead of .text.unlikely mitigates against poor
-  // profile inaccuracy. Techniques such as hugepage remapping can make
-  // conservative decisions at the section granularity.
-  if (config->zKeepTextSectionPrefix)
-    for (StringRef v : {".text.hot.", ".text.unknown.", ".text.unlikely.",
-                        ".text.startup.", ".text.exit.", ".text.split."})
-      if (isSectionPrefix(v, s->name))
-        return v.drop_back();
-
-  for (StringRef v :
-       {".text.", ".rodata.", ".data.rel.ro.", ".data.", ".bss.rel.ro.",
-        ".bss.", ".init_array.", ".fini_array.", ".ctors.", ".dtors.", ".tbss.",
-        ".gcc_except_table.", ".tdata.", ".ARM.exidx.", ".ARM.extab."})
-    if (isSectionPrefix(v, s->name))
-      return v.drop_back();
-
-  return s->name;
-}
-
 static bool needsInterpSection() {
   return !config->relocatable && !config->shared &&
          !config->dynamicLinker.empty() && script->needsInterpSection();

diff  --git a/lld/ELF/Writer.h b/lld/ELF/Writer.h
index 3698544d977be..9c4a5b98451db 100644
--- a/lld/ELF/Writer.h
+++ b/lld/ELF/Writer.h
@@ -51,7 +51,6 @@ struct PhdrEntry {
 };
 
 void addReservedSymbols();
-llvm::StringRef getOutputSectionName(const InputSectionBase *s);
 
 template <class ELFT> uint32_t calcMipsEFlags();