Add -z keep-text-section-prefix

cmdline.cc

@@ -128,6 +128,8 @@ Options:
     -z norelro
   -z defs                     Report undefined symbols (even with --shared)
     -z nodefs
+  -z keep-text-section-prefix Keep .text.{hot,unknown,unlikely,startup,exit} as separate sections in the final binary
+    -z nokeep-text-section-prefix
   -z nodlopen                 Mark DSO not available to dlopen
   -z nodelete                 Mark DSO non-deletable at runtime
   -z nocopyreloc              Do not create copy relocations
@@ -593,6 +595,10 @@ void parse_nonpositional_args(Context<E> &ctx,
       ctx.arg.z_interpose = true;
     } else if (read_z_flag(args, "muldefs")) {
       ctx.arg.allow_multiple_definition = true;
+    } else if (read_z_flag(args, "keep-text-section-prefix")) {
+      ctx.arg.z_keep_text_section_prefix = true;
+    } else if (read_z_flag(args, "nokeep-text-section-prefix")) {
+      ctx.arg.z_keep_text_section_prefix = false;
     } else if (read_flag(args, "no-undefined")) {
       ctx.arg.z_defs = true;
     } else if (read_flag(args, "fatal-warnings")) {

docs/mold.1

@@ -593,6 +593,13 @@ variables reside) are not executable for security reasons. \fB\-z
 execstack\fR makes it executable. \fB\-z noexecstack\fR restores the
 default behavior.
 
+.IP "\fB\-z keep\-text\-section\-prefix\fR"
+.PD 0
+.IP "\fB\-z nokeep\-text\-section\-prefix\fR"
+.PD
+Keep .text.hot, .text.unknown, .text.unlikely, .text.startup
+and .text.exit as separate sections in the final binary.
+
 .IP "\fB\-z relro\fR"
 .PD 0
 .IP "\fB\-z norelro\fR"

mold.h

@@ -1462,11 +1462,10 @@ struct Context {
     bool z_execstack = false;
     bool z_initfirst = false;
     bool z_interpose = false;
+    bool z_keep_text_section_prefix = false;
     bool z_now = false;
     bool z_relro = true;
     i16 default_version = VER_NDX_GLOBAL;
-    std::vector<std::string_view> version_definitions;
-    std::vector<VersionPattern> version_patterns;
     i64 filler = -1;
     i64 spare_dynamic_tags = 5;
     i64 thread_count = -1;
@@ -1483,12 +1482,14 @@ struct Context {
     std::string sysroot;
     std::unique_ptr<std::unordered_set<std::string_view>> retain_symbols_file;
     std::unordered_set<std::string_view> wrap;
+    std::vector<VersionPattern> version_patterns;
     std::vector<std::string_view> auxiliary;
     std::vector<std::string_view> exclude_libs;
     std::vector<std::string_view> filter;
     std::vector<std::string_view> library_paths;
     std::vector<std::string_view> trace_symbol;
     std::vector<std::string_view> undefined;
+    std::vector<std::string_view> version_definitions;
     u64 image_base = 0x200000;
   } arg;
 

output_chunks.cc

@@ -553,12 +553,24 @@ void DynamicSection<E>::copy_buf(Context<E> &ctx) {
   write_vector(ctx.buf + this->shdr.sh_offset, contents);
 }
 
-static std::string_view get_output_name(std::string_view name) {
+template <typename E>
+static std::string_view get_output_name(Context<E> &ctx, std::string_view name) {
+  if (ctx.arg.z_keep_text_section_prefix) {
+    static std::string_view text_prefixes[] = {
+      ".text.hot.", ".text.unknown.", ".text.unlikely.", ".text.startup.",
+      ".text.exit."
+    };
+
+    for (std::string_view prefix : text_prefixes) {
+      std::string_view stem = prefix.substr(0, prefix.size() - 1);
+      if (name == stem || name.starts_with(prefix))
+        return stem;
+    }
+  }
+
   static std::string_view prefixes[] = {
-    ".text.hot.", ".text.unknown.", ".text.unlikely.", ".text.startup.",
-    ".text.exit.", ".text.", ".data.rel.ro.", ".data.", ".rodata.",
-    ".bss.rel.ro.", ".bss.", ".init_array.", ".fini_array.", ".tbss.",
-    ".tdata.", ".gcc_except_table.",
+    ".text.", ".data.rel.ro.", ".data.", ".rodata.", ".bss.rel.ro.", ".bss.",
+    ".init_array.", ".fini_array.", ".tbss.", ".tdata.", ".gcc_except_table.",
   };
 
   for (std::string_view prefix : prefixes) {
@@ -618,7 +630,7 @@ template <typename E>
 OutputSection<E> *
 OutputSection<E>::get_instance(Context<E> &ctx, std::string_view name,
                                u64 type, u64 flags) {
-  name = get_output_name(name);
+  name = get_output_name(ctx, name);
   type = canonicalize_type(name, type);
   flags = flags & ~(u64)SHF_GROUP & ~(u64)SHF_COMPRESSED;
 
@@ -1103,7 +1115,7 @@ template <typename E>
 MergedSection<E> *
 MergedSection<E>::get_instance(Context<E> &ctx, std::string_view name,
                                u64 type, u64 flags) {
-  name = get_output_name(name);
+  name = get_output_name(ctx, name);
   flags = flags & ~(u64)SHF_MERGE & ~(u64)SHF_STRINGS;
 
   auto find = [&]() -> MergedSection * {

test/section-name.sh

@@ -62,7 +62,7 @@ _start:
 .ascii ".gcc_except_table.foo "
 EOF
 
-../mold -o $t/exe $t/a.o
+../mold -o $t/exe $t/a.o -z keep-text-section-prefix
 
 readelf -p .text.hot $t/exe | fgrep -q '.text.hot .text.hot.foo'
 readelf -p .text.unknown $t/exe | fgrep -q '.text.unknown .text.unknown.foo'
@@ -75,4 +75,10 @@ readelf -p .data $t/exe | fgrep -q '.data .data.foo'
 readelf -p .rodata $t/exe | fgrep -q '.rodata .rodata.foo'
 readelf -p .gcc_except_table $t/exe | fgrep -q '.gcc_except_table .gcc_except_table.foo'
 
+../mold -o $t/exe $t/a.o
+! readelf --sections $t/exe | fgrep -q .text.hot || false
+
+../mold -o $t/exe $t/a.o -z nokeep-text-section-prefix
+! readelf --sections $t/exe | fgrep -q .text.hot || false
+
 echo OK