[PATCH] D22649: [ELF] - Linkerscript: ignore AT

[George Rimar via llvm-commits]

grimar created this revision.
grimar added reviewers: ruiu, rafael.
grimar added subscribers: llvm-commits, grimar, evgeny777.

AT is tricky command and we even have a patch for it: D19272
Though looks we do not to support it right now,
but probably it is worth to ignore then.
Patch implements that and just shows warning if it is used.

https://reviews.llvm.org/D22649

Files:
  ELF/LinkerScript.cpp
  test/ELF/linkerscript-at.s

Index: test/ELF/linkerscript-at.s
===================================================================
--- test/ELF/linkerscript-at.s
+++ test/ELF/linkerscript-at.s
@@ -0,0 +1,10 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: echo "SECTIONS { \
+# RUN:  .aaa : AT(0x0) \
+# RUN:  { \
+# RUN:  } \
+# RUN: }" > %t.script
+# RUN: ld.lld -shared %t --script %t.script -o %t2 2>&1 | \
+# RUN:   FileCheck --check-prefix=IGNORED %s
+# IGNORED: AT command is ignored
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -577,6 +577,7 @@
   unsigned readPhdrType();
   void readSymbolAssignment(StringRef Name);
   std::vector<StringRef> readSectionsCommandExpr();
+  void readAt();
 
   const static StringMap<Handler> Cmd;
   ScriptConfiguration &Opt = *ScriptConfig;
@@ -789,10 +790,23 @@
     Opt.Commands.push_back(llvm::make_unique<SymbolAssignment>(".", Expr));
 }
 
+void ScriptParser::readAt() {
+  warning("AT command is ignored");
+  expect("AT");
+  expect("(");
+  while (!Error) {
+    StringRef Tok = next();
+    if (Tok == ")")
+      break;
+  }
+}
+
 void ScriptParser::readOutputSectionDescription(StringRef OutSec) {
   OutputSectionCommand *Cmd = new OutputSectionCommand(OutSec);
   Opt.Commands.emplace_back(Cmd);
   expect(":");
+  if (peek() == "AT")
+    readAt();
   expect("{");
 
   while (!Error && !skip("}")) {


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