Handle parsing AT(ADDR(.foo-bar))

[• espindola]

Summary

The problem we have with it is that anything inside an AT is as expression, so we fail to parse the section name because of the - in it.

[ruiu]

ELF/ScriptParser.cpp

800

I think even if we have to repeat very similar code twice, that's still better than defining a new class for RAII.

[• espindola]

Don't add a RAII class.

[ruiu]

LGTM

[• espindola]

r322801.

ELF/ScriptParser.cpp

SymbolAssignment *ScriptParser::readAssignment(StringRef Name) {
   Expr E = readExpr();
   if (Op == "+=") {
     std::string Loc = getCurrentLocation();
     E = [=] { return add(Script->getSymbolValue(Name, Loc), E()); };
   }
   return make<SymbolAssignment>(Name, E, getCurrentLocation());
 }
 
+namespace {
+// Our lexer is context-aware. This sets the in-expression bit so that
+// it applies different tokenization rules.
+struct RAIIInExpr {
+  bool Old;
+  bool *Ptr;
+  RAIIInExpr(bool *Ptr, bool Val) : Old(*Ptr), Ptr(Ptr) { *Ptr = Val; }
+  ~RAIIInExpr() { *Ptr = Old; }
+};
+} // namespace
+
 // This is an operator-precedence parser to parse a linker
 // script expression.
 Expr ScriptParser::readExpr() {
-  // Our lexer is context-aware. Set the in-expression bit so that
-  // they apply different tokenization rules.
-  bool Orig = InExpr;
-  InExpr = true;
-  Expr E = readExpr1(readPrimary(), 0);
-  InExpr = Orig;
-  return E;
+  RAIIInExpr R(&InExpr, true);
+  return readExpr1(readPrimary(), 0);
 }
 
 static Expr combine(StringRef Op, Expr L, Expr R) {
   if (Op == "+")
     return [=] { return add(L(), R()); };
   if (Op == "-")
     return [=] { return sub(L(), R()); };
   if (Op == "*")
int Size = StringSwitch<int>(Tok)
                  .Default(-1);
   if (Size == -1)
     return nullptr;
   return make<ByteCommand>(readParenExpr(), Size);
 }
 
 StringRef ScriptParser::readParenLiteral() {
   expect("(");
+  RAIIInExpr R(&InExpr, false);
   StringRef Tok = next();
   expect(")");
   return Tok;
 }
 
 static void checkIfExists(OutputSection *Cmd, StringRef Location) {
   if (Cmd->Location.empty() && Script->ErrorOnMissingSection)
     error(Location + ": undefined section " + Cmd->Name);

test/ELF/linkerscript/parse-section-in-addr.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+
+# RUN: echo "SECTIONS {                                   \
+# RUN:         .foo-bar : AT(ADDR(.foo-bar)) { *(.text) } \
+# RUN:       }" > %t.script
+# RUN: ld.lld -o %t.so --script %t.script %t.o -shared
+# RUN: llvm-readelf -S %t.so | FileCheck %s
+
+# CHECK: .foo-bar