Avoid miscompilation of variadic functions

include/mull/Filters/Filters.h

@@ -29,6 +29,7 @@ class Filters {
   void enableFilePathFilter();
   void enableGitDiffFilter();
   void enableBlockAddressFilter();
+  void enableVariadicFunctionFilter();
   CoverageFilter *enableCoverageFilter(const std::string &profileName,
                                        const std::vector<std::string> &objects);
 

include/mull/Filters/VariadicFunctionFilter.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "mull/Filters/FunctionFilter.h"
+
+namespace mull {
+
+class VariadicFunctionFilter : public FunctionFilter {
+public:
+  bool shouldSkip(llvm::Function *function) override;
+  std::string name() override;
+  ~VariadicFunctionFilter() override = default;
+};
+} // namespace mull

lib/CMakeLists.txt

@@ -83,6 +83,7 @@ set(mull_sources
   Filters/BlockAddressFunctionFilter.cpp
   Filters/Filters.cpp
   Filters/CoverageFilter.cpp
+  Filters/VariadicFunctionFilter.cpp
 
   JunkDetection/CXX/Visitors/ScalarValueVisitor.cpp
   MutantRunner.cpp

lib/Driver.cpp

@@ -346,6 +346,7 @@ void mull::mutateBitcode(llvm::Module &module) {
   filters.enableFilePathFilter();
   filters.enableGitDiffFilter();
   filters.enableBlockAddressFilter();
+  filters.enableVariadicFunctionFilter();
 
   std::string cxxCompilationFlags;
   for (auto &flag : configuration.compilerFlags) {

lib/Filters/Filters.cpp

@@ -6,6 +6,7 @@
 #include "mull/Filters/FilePathFilter.h"
 #include "mull/Filters/GitDiffFilter.h"
 #include "mull/Filters/NoDebugInfoFilter.h"
+#include "mull/Filters/VariadicFunctionFilter.h"
 #include <llvm/Support/FileSystem.h>
 #include <sstream>
 
@@ -108,3 +109,9 @@ void Filters::enableBlockAddressFilter() {
   storage.emplace_back(filter);
   functionFilters.push_back(filter);
 }
+
+void Filters::enableVariadicFunctionFilter() {
+  auto filter = new mull::VariadicFunctionFilter;
+  storage.emplace_back(filter);
+  functionFilters.push_back(filter);
+}

lib/Filters/VariadicFunctionFilter.cpp

@@ -0,0 +1,12 @@
+#include "mull/Filters/VariadicFunctionFilter.h"
+#include <llvm/IR/Function.h>
+
+using namespace mull;
+
+bool VariadicFunctionFilter::shouldSkip(llvm::Function *function) {
+  return function->isVarArg();
+}
+
+std::string VariadicFunctionFilter::name() {
+  return "variadic functions";
+}

tests-lit/tests/filters/blockaddress/main.c

@@ -17,5 +17,5 @@ int main(int argc, char **argv) {
 // RUN: %clang_cc %pass_mull_ir_frontend -g %s -o %s.exe
 // RUN: %s.exe | %filecheck %s --dump-input=fail --strict-whitespace --match-full-lines --check-prefix=CHECK1
 // CHECK1:label1
-// RUN: %s.exe | %filecheck %s --dump-input=fail --strict-whitespace --match-full-lines --check-prefix=CHECK2
-// CHECK2:label1
+// RUN: %s.exe x | %filecheck %s --dump-input=fail --strict-whitespace --match-full-lines --check-prefix=CHECK2
+// CHECK2:label2

tests-lit/tests/filters/variadic-functions/main.c

@@ -0,0 +1,56 @@
+// clang-format off
+#include <stdarg.h>
+
+extern unsigned long strlen(const char *s);
+extern char *strcpy(char * dst, const char * src);
+extern int printf(const char *, ...);
+extern void abort();
+
+static int a = 10;
+static int b = 32;
+static int c = 0;
+
+void fill_in(const char *what, int n, ...) {
+  c = a + b;
+  va_list args;
+  va_start(args, n);
+  for (int i = 0; i < n; ++i) {
+    char *buf = va_arg(args, char *);
+    int w_len = strlen(what);
+    int b_len = strlen(buf);
+    if (w_len > b_len) {
+      printf("CRASHING\n");
+      abort();
+    }
+    strcpy(buf, what);
+    buf[i] = '_';
+    buf[b_len] = '\0';
+  }
+  va_end(args);
+}
+
+int main() {
+  char b1[16] = "initialize";
+  char b2[16] = "initialize";
+  char b3[16] = "initialize";
+  char b4[16] = "initialize";
+  fill_in("test", 4, b1, b2, b3, b4);
+  printf("%s\n", b1);
+  printf("%s\n", b2);
+  printf("%s\n", b3);
+  printf("%s\n", b4);
+  printf("%d\n", c);
+  return 0;
+}
+
+// RUN: %clang_cc %pass_mull_ir_frontend -g %s -o %s.exe
+// RUN: %s.exe | %filecheck %s --dump-input=fail --strict-whitespace --match-full-lines
+// CHECK:_est
+// CHECK-NEXT:t_st
+// CHECK-NEXT:te_t
+// CHECK-NEXT:tes_
+// CHECK-NEXT:42
+// CHECK-EMPTY
+
+// RUN: unset TERM; %mull_runner %s.exe | %filecheck %s --dump-input=fail --strict-whitespace --match-full-lines --check-prefix=CHECK_MUTANT
+// CHECK_MUTANT:[info] No mutants found. Mutation score: infinitely high

tests-lit/tests/filters/variadic-functions/mull.yml

@@ -0,0 +1,3 @@
+mutators:
+  - cxx_add_to_sub
+quiet: false