[ELF] Fix assertion failure when PROVIDE/HIDDEN/PROVIDE_HIDDEN does not have =

Author: MaskRay

lld/ELF/ScriptParser.cpp

@@ -1017,7 +1017,14 @@ std::array<uint8_t, 4> ScriptParser::readFill() {
 
 SymbolAssignment *ScriptParser::readProvideHidden(bool provide, bool hidden) {
   expect("(");
-  SymbolAssignment *cmd = readSymbolAssignment(next());
+  StringRef name = next(), eq = peek();
+  if (eq != "=") {
+    setError("= expected, but got " + next());
+    while (!atEOF() && next() != ")")
+      ;
+    return nullptr;
+  }
+  SymbolAssignment *cmd = readSymbolAssignment(name);
   cmd->provide = provide;
   cmd->hidden = hidden;
   expect(")");

lld/test/ELF/linkerscript/symbols.s

@@ -73,6 +73,11 @@
 # SIMPLE2: 0000000000000100 g       *ABS*  0000000000000000 bar
 # SIMPLE2: 0000000000000100 g       *ABS*  0000000000000000 baz
 
+# RUN: echo 'PROVIDE(somesym + 1);' > %t.script
+# RUN: not ld.lld -T %t.script %t -o /dev/null 2>&1 | FileCheck %s --check-prefix=PROVIDE-ERR
+
+# PROVIDE-ERR: {{.*}}:1: = expected, but got +
+
 .global _start
 _start:
  nop