Recommit: Detect incorrect FileCheck variable CLI definition

Summary:
While the backend code of FileCheck relies on definition of variable
from the command-line to have an equal sign '=' and a variable name
before that, the frontend does not actually enforce it. This leads to
FileCheck crashing when invoked with invalid syntax for the -D option.

This patch adds the missing validation in the frontend. It also makes
the -D option an AlwaysPrefix option to be able to detect -D=FOO as
being a define without variable and -D as missing its value.

Copyright:
- Linaro (changes in version 2 of revision D55940)
- GraphCore (changes in later versions)

Reviewers: jdenny

Subscribers: JonChesterfield, hiraditya, kristina, probinson,
llvm-commits

Differential Revision: https://reviews.llvm.org/D55940

llvm-svn: 353173

1 files changed, 22 insertions, 4 deletions

diff --git a/llvm/utils/FileCheck/FileCheck.cpp b/llvm/utils/FileCheck/FileCheck.cpp
index eb1b5dd..0d5f38a 100644
--- a/llvm/utils/FileCheck/FileCheck.cpp
+++ b/llvm/utils/FileCheck/FileCheck.cpp
@@ -50,9 +50,10 @@ static cl::list<std::string> ImplicitCheckNot(
              "this pattern occur which are not matched by a positive pattern"),
     cl::value_desc("pattern"));
 
-static cl::list<std::string> GlobalDefines("D", cl::Prefix,
-    cl::desc("Define a variable to be used in capture patterns."),
-    cl::value_desc("VAR=VALUE"));
+static cl::list<std::string>
+    GlobalDefines("D", cl::AlwaysPrefix,
+                  cl::desc("Define a variable to be used in capture patterns."),
+                  cl::value_desc("VAR=VALUE"));
 
 static cl::opt<bool> AllowEmptyInput(
     "allow-empty", cl::init(false),
@@ -525,8 +526,25 @@ int main(int argc, char **argv) {
   for (auto CheckNot : ImplicitCheckNot)
     Req.ImplicitCheckNot.push_back(CheckNot);
 
-  for (auto G : GlobalDefines)
+  bool GlobalDefineError = false;
+  for (auto G : GlobalDefines) {
+    size_t EqIdx = G.find('=');
+    if (EqIdx == std::string::npos) {
+      errs() << "Missing equal sign in command-line definition '-D" << G
+             << "'\n";
+      GlobalDefineError = true;
+      continue;
+    }
+    if (EqIdx == 0) {
+      errs() << "Missing pattern variable name in command-line definition '-D"
+             << G << "'\n";
+      GlobalDefineError = true;
+      continue;
+    }
     Req.GlobalDefines.push_back(G);
+  }
+  if (GlobalDefineError)
+    return 2;
 
   Req.AllowEmptyInput = AllowEmptyInput;
   Req.EnableVarScope = EnableVarScope;