[clang] 6ae0e6d - Don't crash when given an empty input filename. (#184718)

[via cfe-commits]

Author: Richard Smith
Date: 2026-03-05T12:50:03-08:00
New Revision: 6ae0e6d5fb2cff91f9aef9b19adbc144fe8d20ff

URL: https://github.com/llvm/llvm-project/commit/6ae0e6d5fb2cff91f9aef9b19adbc144fe8d20ff
DIFF: https://github.com/llvm/llvm-project/commit/6ae0e6d5fb2cff91f9aef9b19adbc144fe8d20ff.diff

LOG: Don't crash when given an empty input filename. (#184718)

Commands such as `clang -- ''` hit two different crash bugs: a buffer
overflow caused by using a `memcmp` that might be larger than the input,
and a bogus assert in the option parser when attempting typo correction.

Added: 
    clang/test/Driver/empty_arg.c

Modified: 
    clang/lib/Driver/Driver.cpp
    llvm/lib/Option/OptTable.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index afa1884d94b70..420340aaab885 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -3082,7 +3082,7 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
           InputTypeArg->claim();
 
         // stdin must be handled specially.
-        if (memcmp(Value, "-", 2) == 0) {
+        if (strcmp(Value, "-") == 0) {
           if (IsFlangMode()) {
             Ty = types::TY_Fortran;
           } else if (IsDXCMode()) {

diff  --git a/clang/test/Driver/empty_arg.c b/clang/test/Driver/empty_arg.c
new file mode 100644
index 0000000000000..94ed8f13cbec4
--- /dev/null
+++ b/clang/test/Driver/empty_arg.c
@@ -0,0 +1,2 @@
+// RUN: not %clang -- "" 2>&1 | FileCheck %s
+// CHECK: error: no such file or directory: ''

diff  --git a/llvm/lib/Option/OptTable.cpp b/llvm/lib/Option/OptTable.cpp
index 065036cedc2ae..8444675b847e6 100644
--- a/llvm/lib/Option/OptTable.cpp
+++ b/llvm/lib/Option/OptTable.cpp
@@ -264,8 +264,6 @@ unsigned OptTable::internalFindNearest(
     StringRef Option, std::string &NearestString, unsigned MinimumLength,
     unsigned MaximumDistance,
     std::function<bool(const Info &)> ExcludeOption) const {
-  assert(!Option.empty());
-
   // Consider each [option prefix + option name] pair as a candidate, finding
   // the closest match.
   unsigned BestDistance =