[binutils-gdb] Allows linker scripts to set the SEC_READONLY flag.

[Nick Clifton]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6b86da53d5ee2022b9065f445d23356190380746

commit 6b86da53d5ee2022b9065f445d23356190380746
Author: Luca Boccassi <luca.boccassi@microsoft.com>
Date:   Wed Jul 21 14:32:03 2021 +0100

    Allows linker scripts to set the SEC_READONLY flag.
    
    * ld.texi: Document new output section type.
    * ldgram.y: Add new token.
    * ldlang.c: Handle the new flag.
    * ldlang.h: Add readonly_section to list of section types.
    * ldlex.l: Add a new identifier.
    * testsuite/ld-scripts/output-section-types.t: New example linker script.
    * testsuite/ld-scripts/output-section-types.d: Test driver.
    * testsyute/ld-scripts/script.exp: Run the new test.

Diff:
---
 ld/ld.texi                                     |  2 ++
 ld/ldgram.y                                    |  2 ++
 ld/ldlang.c                                    |  6 ++++++
 ld/ldlang.h                                    |  3 ++-
 ld/ldlex.l                                     |  1 +
 ld/testsuite/ld-scripts/output-section-types.d | 13 +++++++++++++
 ld/testsuite/ld-scripts/output-section-types.t |  7 +++++++
 ld/testsuite/ld-scripts/script.exp             |  1 +
 8 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/ld/ld.texi b/ld/ld.texi
index b6d8dccea0b..60bb071fb79 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -5474,6 +5474,8 @@ parentheses.  The following types are defined:
 @item NOLOAD
 The section should be marked as not loadable, so that it will not be
 loaded into memory when the program is run.
+@item READONLY
+The section should be marked as read-only.
 @item DSECT
 @itemx COPY
 @itemx INFO
diff --git a/ld/ldgram.y b/ld/ldgram.y
index dd911f46169..31e0071c6fc 100644
--- a/ld/ldgram.y
+++ b/ld/ldgram.y
@@ -139,6 +139,7 @@ static int error_index;
 %token REGION_ALIAS
 %token LD_FEATURE
 %token NOLOAD DSECT COPY INFO OVERLAY
+%token READONLY
 %token DEFINED TARGET_K SEARCH_DIR MAP ENTRY
 %token <integer> NEXT
 %token SIZEOF ALIGNOF ADDR LOADADDR MAX_K MIN_K
@@ -1123,6 +1124,7 @@ type:
 	|  COPY    { sectype = noalloc_section; }
 	|  INFO    { sectype = noalloc_section; }
 	|  OVERLAY { sectype = noalloc_section; }
+	|  READONLY { sectype = readonly_section; }
 	;
 
 atype:
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 37b64c89ee1..2610be995ca 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -2639,6 +2639,9 @@ lang_add_section (lang_statement_list_type *ptr,
     case noalloc_section:
       flags &= ~SEC_ALLOC;
       break;
+    case readonly_section:
+      flags |= SEC_READONLY;
+      break;
     case noload_section:
       flags &= ~SEC_LOAD;
       flags |= SEC_NEVER_LOAD;
@@ -4232,6 +4235,9 @@ map_input_to_output_sections
 	    case noalloc_section:
 	      flags = SEC_HAS_CONTENTS;
 	      break;
+	    case readonly_section:
+	      flags |= SEC_READONLY;
+	      break;
 	    case noload_section:
 	      if (bfd_get_flavour (link_info.output_bfd)
 		  == bfd_target_elf_flavour)
diff --git a/ld/ldlang.h b/ld/ldlang.h
index 6fbe16d97d9..f68ae27b409 100644
--- a/ld/ldlang.h
+++ b/ld/ldlang.h
@@ -121,7 +121,8 @@ enum section_type
   first_overlay_section,
   overlay_section,
   noload_section,
-  noalloc_section
+  noalloc_section,
+  readonly_section
 };
 
 /* This structure holds a list of program headers describing
diff --git a/ld/ldlex.l b/ld/ldlex.l
index c1b15263587..25b4bcaae01 100644
--- a/ld/ldlex.l
+++ b/ld/ldlex.l
@@ -294,6 +294,7 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([*?.$_a-zA-Z0-9\[\]\-\!\^\\]|::)*
 <BOTH,SCRIPT>"SORT_BY_INIT_PRIORITY"	{ RTOKEN(SORT_BY_INIT_PRIORITY); }
 <BOTH,SCRIPT>"SORT_NONE"		{ RTOKEN(SORT_NONE); }
 <EXPRESSION,BOTH,SCRIPT>"NOLOAD"	{ RTOKEN(NOLOAD);}
+<EXPRESSION,BOTH,SCRIPT>"READONLY"	{ RTOKEN(READONLY);}
 <EXPRESSION,BOTH,SCRIPT>"DSECT"		{ RTOKEN(DSECT);}
 <EXPRESSION,BOTH,SCRIPT>"COPY"		{ RTOKEN(COPY);}
 <EXPRESSION,BOTH,SCRIPT>"INFO"		{ RTOKEN(INFO);}
diff --git a/ld/testsuite/ld-scripts/output-section-types.d b/ld/testsuite/ld-scripts/output-section-types.d
new file mode 100644
index 00000000000..ab124fa4dd7
--- /dev/null
+++ b/ld/testsuite/ld-scripts/output-section-types.d
@@ -0,0 +1,13 @@
+#ld: -Toutput-section-types.t
+#source: align2a.s
+#objdump: -h
+#target: [is_elf_format]
+
+#...
+  . \.rom.*
+[ 	]+ALLOC, READONLY
+  . \.ro.*
+[ 	]+CONTENTS, ALLOC, LOAD, READONLY, DATA
+  . \.over.*
+[ 	]+CONTENTS, READONLY
+#pass
diff --git a/ld/testsuite/ld-scripts/output-section-types.t b/ld/testsuite/ld-scripts/output-section-types.t
new file mode 100644
index 00000000000..d8fdfda1a03
--- /dev/null
+++ b/ld/testsuite/ld-scripts/output-section-types.t
@@ -0,0 +1,7 @@
+SECTIONS {
+  .rom  (NOLOAD)   : { LONG(1234); }
+  .ro   (READONLY) : { LONG(5678); }
+  .over (OVERLAY)  : { LONG(0123); }
+  /DISCARD/        : { *(*) }
+
+}
diff --git a/ld/testsuite/ld-scripts/script.exp b/ld/testsuite/ld-scripts/script.exp
index 961cd08c4b1..ff50199b3ae 100644
--- a/ld/testsuite/ld-scripts/script.exp
+++ b/ld/testsuite/ld-scripts/script.exp
@@ -229,6 +229,7 @@ foreach test_script $test_script_list {
 
 run_dump_test "align-with-input"
 run_dump_test "pr20302"
+run_dump_test "output-section-types"
 
 run_dump_test "segment-start" {{name (default)}}
 run_dump_test "segment-start" {{name (overridden)} \