[PATCH] D120045: [lld][ELF] support nested special directives in output sections

[Luca Boccassi via Phabricator via llvm-commits]

bluca created this revision.
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bfd recently added support for nesting special directives as:
(FOO (BAR = BAZ)). Support this syntax in lld too for source input
compatibility, and simply skip over unknown directives.

https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c212f39d9a82c6c09f4a1447d9d2ff09843827c5


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120045

Files:
  lld/ELF/ScriptParser.cpp
  lld/test/ELF/linkerscript/custom-section-type.s


Index: lld/test/ELF/linkerscript/custom-section-type.s
===================================================================
--- lld/test/ELF/linkerscript/custom-section-type.s
+++ lld/test/ELF/linkerscript/custom-section-type.s
@@ -61,7 +61,7 @@
 #--- a.lds
 SECTIONS {
   progbits (TYPE=SHT_PROGBITS) : { BYTE(1) }
-  note (TYPE = SHT_NOTE) : { BYTE(7) *(note) }
+  note (FOOBAR (TYPE = SHT_NOTE)) : { BYTE(7) *(note) }
   nobits ( TYPE=SHT_NOBITS) : { BYTE(8) }
   init_array (TYPE=SHT_INIT_ARRAY ) : { QUAD(myinit) }
   fini_array (TYPE=SHT_FINI_ARRAY) : { QUAD(15) }
Index: lld/ELF/ScriptParser.cpp
===================================================================
--- lld/ELF/ScriptParser.cpp
+++ lld/ELF/ScriptParser.cpp
@@ -798,14 +798,13 @@
 // Tries to read the special directive for an output section definition which
 // can be one of following: "(NOLOAD)", "(COPY)", "(INFO)", "(OVERLAY)", and
 // "(TYPE=<value>)".
+// Also supports nesting special directives as (FOO (BAR)), as ld.bfd does.
+// Unknown directives are simply skipped over.
 // Tok1 and Tok2 are next 2 tokens peeked. See comment for
 // readSectionAddressType below.
 bool ScriptParser::readSectionDirective(OutputSection *cmd, StringRef tok1, StringRef tok2) {
   if (tok1 != "(")
     return false;
-  if (tok2 != "NOLOAD" && tok2 != "COPY" && tok2 != "INFO" &&
-      tok2 != "OVERLAY" && tok2 != "TYPE")
-    return false;
 
   expect("(");
   if (consume("NOLOAD")) {
@@ -826,10 +825,15 @@
       cmd->type = readExpr()().getValue();
     }
     cmd->typeIsSet = true;
-  } else {
-    skip(); // This is "COPY", "INFO" or "OVERLAY".
+  } else if (consume("COPY") || consume("INFO") || consume("OVERLAY")) {
     cmd->nonAlloc = true;
+  } else {
+    skip();
   }
+
+  if (peek() == "(" && !readSectionDirective(cmd, "(", peek2()))
+    return false;
+
   expect(")");
   return true;
 }


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