Detect linker script INCLUDE cycles.

[ruiu]

Summary

Detect linker script INCLUDE cycles.

[davide]

lld/ELF/ScriptParser.cpp

115

The comment might/should be committed separately?

[davide]

Other than that, lg.

[ruiu]

lld/ELF/ScriptParser.cpp

115

Done.

[grimar]

lld/trunk/test/ELF/linkerscript/include-cycle.s

11 ↗

(On Diff #114035)

I think it worth to include file name causes cycle.

15 ↗

(On Diff #114035)

You should not need any code in this testcase.

[grimar]

lld/trunk/test/ELF/linkerscript/include-cycle.s

11 ↗

(On Diff #114035)

Taking this back. We will print line where error happens, so filename will be there.
I would add it to test for demonstration though.

lld/ELF/ScriptParser.cpp

 #include "LinkerScript.h"
 #include "Memory.h"
 #include "OutputSections.h"
 #include "ScriptLexer.h"
 #include "Symbols.h"
 #include "Target.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include <cassert>
 #include <limits>
private:
   // For parsing version script.
   std::vector<SymbolVersion> readVersionExtern();
   void readAnonymousDeclaration();
   void readVersionDeclaration(StringRef VerStr);
 
   std::pair<std::vector<SymbolVersion>, std::vector<SymbolVersion>>
   readSymbols();
 
+  // True if a script being read is in a subdirectory specified by -sysroot.
   bool IsUnderSysroot;
+
+  // A set to detect an INCLUDE() cycle.
+  StringSet<> Seen;
 };
 } // namespace
 
 static StringRef unquote(StringRef S) {
   if (S.startswith("\""))
     return S.substr(1, S.size() - 2);
   return S;
 }
while (!ErrorCount && !consume(")")) {
     else
       addFile(unquote(next()));
   }
 }
 
 void ScriptParser::readInclude() {
   StringRef Tok = unquote(next());
 
+  if (!Seen.insert(Tok).second) {
+    setError("there is a cycle in linker script INCLUDEs");
+    return;
+  }
+
   // https://sourceware.org/binutils/docs/ld/File-Commands.html:
   // The file will be searched for in the current directory, and in any
   // directory specified with the -L option.
   if (sys::fs::exists(Tok)) {
     if (Optional<MemoryBufferRef> MB = readFile(Tok))
       tokenize(*MB);
     return;
   }

lld/test/ELF/linkerscript/include-cycle.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+
+# RUN: echo INCLUDE %t1.script > %t1.script
+# RUN: not ld.lld %t.o %t1.script 2>&1 | FileCheck %s
+
+# RUN: echo INCLUDE %t2.script > %t1.script
+# RUN: echo INCLUDE %t1.script > %t2.script
+# RUN: not ld.lld %t.o %t1.script 2>&1 | FileCheck %s
+
+# CHECK: there is a cycle in linker script INCLUDEs
+
+.globl _start
+_start:
+  ret