From a392df933c938997631db2e7b8df729fb258f193 Mon Sep 17 00:00:00 2001
From: Florian Hahn <florian.hahn@arm.com>
Date: Wed, 20 Dec 2017 11:32:43 +0000
Subject: [PATCH] [TargetParser] Check size before accessing architecture
 version.

Summary:
This fixes a crash when invalid -march options like `armv` are provided.

Based on a patch by Will Lovett.


Reviewers: rengolin, samparker, mcrosier

Reviewed By: samparker

Subscribers: aemerson, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D41429

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321166 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Support/TargetParser.cpp           | 4 ++--
 unittests/Support/TargetParserTest.cpp | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/Support/TargetParser.cpp b/lib/Support/TargetParser.cpp
index ea12d8001a3..b96ca084e9b 100644
--- a/lib/Support/TargetParser.cpp
+++ b/lib/Support/TargetParser.cpp
@@ -537,7 +537,7 @@ StringRef llvm::AArch64::getDefaultCPU(StringRef Arch) {
 }
 
 unsigned llvm::AArch64::checkArchVersion(StringRef Arch) {
-  if (Arch[0] == 'v' && std::isdigit(Arch[1]))
+  if (Arch.size() >= 2 && Arch[0] == 'v' && std::isdigit(Arch[1]))
     return (Arch[1] - 48);
   return 0;
 }
@@ -633,7 +633,7 @@ StringRef llvm::ARM::getCanonicalArchName(StringRef Arch) {
   // Only match non-marketing names
   if (offset != StringRef::npos) {
     // Must start with 'vN'.
-    if (A[0] != 'v' || !std::isdigit(A[1]))
+    if (A.size() >= 2 && (A[0] != 'v' || !std::isdigit(A[1])))
       return Error;
     // Can't have an extra 'eb'.
     if (A.find("eb") != StringRef::npos)
diff --git a/unittests/Support/TargetParserTest.cpp b/unittests/Support/TargetParserTest.cpp
index dcef40345f0..48fffca1aa1 100644
--- a/unittests/Support/TargetParserTest.cpp
+++ b/unittests/Support/TargetParserTest.cpp
@@ -278,6 +278,12 @@ TEST(TargetParserTest, testARMCPU) {
                          "7-S"));
 }
 
+TEST(TargetParserTest, testInvalidARMArch) {
+  auto InvalidArchStrings = {"armv", "armv99", "noarm"};
+  for (const char* InvalidArch : InvalidArchStrings)
+    EXPECT_EQ(ARM::parseArch(InvalidArch), ARM::ArchKind::INVALID);
+}
+
 bool testARMArch(StringRef Arch, StringRef DefaultCPU, StringRef SubArch,
                  unsigned ArchAttr) {
   ARM::ArchKind AK = ARM::parseArch(Arch);
-- 
2.11.0