[ELF] - Linkerscript: implement NOLOAD section type.

This is PR32351

Each output section may have a type. The type is a keyword in parentheses.
(https://sourceware.org/binutils/docs/ld/Output-Section-Type.html#Output-Section-Type)
This patch support only one type, it is NOLOAD.
If output section has such type, we force it to be SHT_NOBITS. 

More details are available on a review page.

Differential revision: https://reviews.llvm.org/D33647

llvm-svn: 304925

1 files changed, 14 insertions, 4 deletions

diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index fc6b8e3..61e682c 100644
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -568,10 +568,20 @@ ScriptParser::readOutputSectionDescription(StringRef OutSec) {
   OutputSectionCommand *Cmd =
       Script->createOutputSectionCommand(OutSec, getCurrentLocation());
 
-  // Read an address expression.
-  // https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
-  if (peek() != ":")
-    Cmd->AddrExpr = readExpr();
+  if (peek() != ":") {
+    // Read an address expression.
+    // https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
+    if (peek() != "(")
+      Cmd->AddrExpr = readExpr();
+
+    // Read a section type. Currently, only NOLOAD is supported.
+    // https://sourceware.org/binutils/docs/ld/Output-Section-Type.html
+    if (consume("(")) {
+      expect("NOLOAD");
+      expect(")");
+      Cmd->Noload = true;
+    }
+  }
 
   expect(":");