[PATCH] D45841: Keep the output text sections with prefixes ".text.hot" , ".text.unlikely", ".text.startup", ".text.exit" separate

[Sriraman Tallam via Phabricator via llvm-commits]

tmsriram updated this revision to Diff 145097.
tmsriram added a comment.

New option -z keep-text-section-prefix.

- Changed to have this feature enabled by an option
- The default is not changed.


https://reviews.llvm.org/D45841

Files:
  ELF/Config.h
  ELF/Driver.cpp
  ELF/Writer.cpp


Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -88,6 +88,12 @@
 };
 } // anonymous namespace
 
+static bool isSectionPrefix(StringRef PrefixName, StringRef SectionName) {
+  if (SectionName.startswith(PrefixName) || SectionName == PrefixName.drop_back())
+    return true;
+  return false;
+}
+
 StringRef elf::getOutputSectionName(InputSectionBase *S) {
   if (Config->Relocatable)
     return S->Name;
@@ -104,13 +110,23 @@
     }
   }
 
+  // This check is for -z keep-text-section-prefix.  This option separates text
+  // sections with prefix ".text.hot" or ".text.unlikely" or ".text.startup" or
+  // ".text.exit".
+  if (Config->ZKeeptextsectionprefix) {
+    for (StringRef V :
+         {".text.hot.", ".text.unlikely.", ".text.startup.", ".text.exit."}) {
+      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."}) {
-    StringRef Prefix = V.drop_back();
-    if (S->Name.startswith(V) || S->Name == Prefix)
-      return Prefix;
+    if (isSectionPrefix(V, S->Name))
+      return V.drop_back();
   }
 
   // CommonSection is identified as "COMMON" in linker scripts.
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -761,6 +761,8 @@
       Args.hasFlag(OPT_warn_symbol_ordering, OPT_no_warn_symbol_ordering, true);
   Config->ZCombreloc = getZFlag(Args, "combreloc", "nocombreloc", true);
   Config->ZCopyreloc = getZFlag(Args, "copyreloc", "nocopyreloc", true);
+  Config->ZKeeptextsectionprefix = getZFlag(
+      Args, "keep-text-section-prefix", "nokeep-text-section-prefix", false);
   Config->ZExecstack = getZFlag(Args, "execstack", "noexecstack", false);
   Config->ZHazardplt = hasZOption(Args, "hazardplt");
   Config->ZNodelete = hasZOption(Args, "nodelete");
Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -167,6 +167,7 @@
   bool WriteAddends;
   bool ZCombreloc;
   bool ZCopyreloc;
+  bool ZKeeptextsectionprefix;
   bool ZExecstack;
   bool ZHazardplt;
   bool ZNodelete;


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