[lld] r305006 - Fix a bug in output section directive.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Thu Jun  8 14:47:16 2017
New Revision: 305006

URL: http://llvm.org/viewvc/llvm-project?rev=305006&view=rev
Log:
Fix a bug in output section directive.

Previously, it couldn't parse

  SECTIONS .text (0x1000) : { *(.text) }

because "(" was interpreted as the begining of the "(NOLOAD)" directive.

Modified:
    lld/trunk/ELF/ScriptParser.cpp
    lld/trunk/test/ELF/linkerscript/noload.s

Modified: lld/trunk/ELF/ScriptParser.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/ScriptParser.cpp?rev=305006&r1=305005&r2=305006&view=diff
==============================================================================
--- lld/trunk/ELF/ScriptParser.cpp (original)
+++ lld/trunk/ELF/ScriptParser.cpp Thu Jun  8 14:47:16 2017
@@ -76,6 +76,7 @@ private:
   BytesDataCommand *readBytesDataCommand(StringRef Tok);
   uint32_t readFill();
   uint32_t parseFill(StringRef Tok);
+  void readSectionAddressType(OutputSectionCommand *Cmd);
   OutputSectionCommand *readOutputSectionDescription(StringRef OutSec);
   std::vector<StringRef> readOutputSectionPhdrs();
   InputSectionDescription *readInputSectionDescription(StringRef Tok);
@@ -563,26 +564,42 @@ uint32_t ScriptParser::readFill() {
   return V;
 }
 
-OutputSectionCommand *
-ScriptParser::readOutputSectionDescription(StringRef OutSec) {
-  OutputSectionCommand *Cmd =
-      Script->createOutputSectionCommand(OutSec, getCurrentLocation());
-
-  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");
+// Reads an expression and/or the special directive "(NOLOAD)" for an
+// output section definition.
+//
+// An output section name can be followed by an address expression
+// and/or by "(NOLOAD)". This grammar is not LL(1) because "(" can be
+// interpreted as either the beginning of some expression or "(NOLOAD)".
+//
+// https://sourceware.org/binutils/docs/ld/Output-Section-Address.html
+// https://sourceware.org/binutils/docs/ld/Output-Section-Type.html
+void ScriptParser::readSectionAddressType(OutputSectionCommand *Cmd) {
+  if (consume("(")) {
+    if (consume("NOLOAD")) {
       expect(")");
       Cmd->Noload = true;
+      return;
     }
+    Cmd->AddrExpr = readExpr();
+    expect(")");
+  } else {
+    Cmd->AddrExpr = readExpr();
   }
 
+  if (consume("(")) {
+    expect("NOLOAD");
+    expect(")");
+    Cmd->Noload = true;
+  }
+}
+
+OutputSectionCommand *
+ScriptParser::readOutputSectionDescription(StringRef OutSec) {
+  OutputSectionCommand *Cmd =
+      Script->createOutputSectionCommand(OutSec, getCurrentLocation());
+
+  if (peek() != ":")
+    readSectionAddressType(Cmd);
   expect(":");
 
   if (consume("AT"))

Modified: lld/trunk/test/ELF/linkerscript/noload.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/noload.s?rev=305006&r1=305005&r2=305006&view=diff
==============================================================================
--- lld/trunk/test/ELF/linkerscript/noload.s (original)
+++ lld/trunk/test/ELF/linkerscript/noload.s Thu Jun  8 14:47:16 2017
@@ -2,7 +2,7 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 # RUN: echo "SECTIONS { \
 # RUN:        .data_noload_a (NOLOAD) : { *(.data_noload_a) } \
-# RUN:        .data_noload_b 0x10000 (NOLOAD) : { *(.data_noload_b) } };" > %t.script
+# RUN:        .data_noload_b (0x10000) (NOLOAD) : { *(.data_noload_b) } };" > %t.script
 # RUN: ld.lld -o %t --script %t.script %t.o
 # RUN: llvm-readobj --symbols -sections %t