[ELF] Emit only one error if -z max-page-size without value

In r305364, Rui changed the mechanism that parses -z option values slightly.
This caused a bug, as demonstrated by this test, which now fails:

---
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
# RUN: ld.lld %t.o -o %t -z max-page-size

.global _start
_start:
  nop
---

Before, the link succeeded and set the max-page-size to the target default.

After we get the following two error messages:
"invalid max-page-size: "
"max-page-size: value isn't a power of 2"

The latter error is because an uninitialised variable ends up being passed back
to getMaxPageSize).

This change ensures we only get the first error.

Reviewers: ruiu

Differential Revision: https://reviews.llvm.org/D34234

llvm-svn: 305679

2 files changed, 10 insertions, 1 deletions

diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index c87ffa26af8..1d966b45444 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -301,7 +301,7 @@ static uint64_t getZOptionValue(opt::InputArgList &Args, StringRef Key,
   for (auto *Arg : Args.filtered(OPT_z)) {
     std::pair<StringRef, StringRef> KV = StringRef(Arg->getValue()).split('=');
     if (KV.first == Key) {
-      uint64_t Result;
+      uint64_t Result = Default;
       if (!to_integer(KV.second, Result))
         error("invalid " + Key + ": " + KV.second);
       return Result;
diff --git a/lld/test/ELF/invalid-z.s b/lld/test/ELF/invalid-z.s
new file mode 100644
index 00000000000..10415526e0c
--- /dev/null
+++ b/lld/test/ELF/invalid-z.s
@@ -0,0 +1,9 @@
+# REQUIRES: x86

+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o

+# RUN: not ld.lld %t.o -o %t -z max-page-size 2>&1 | FileCheck %s

+# CHECK: invalid max-page-size

+# CHECK-NOT: error

+

+.global _start

+_start:

+  nop