tests: add support for dynamically skipping tests based on llvm version

Some tests are useful but are either broken on individual LLVM versions
or before/after an LLVM version. Add new options to the test TOML that
let us skip tests dynamically based on too old/too new/explicitly
skipped LLVM major versions.

Test plan:
- CI
- Used in stacked PRs

Author: JakeHillion

oi/OICompiler.cpp

@@ -738,4 +738,8 @@ std::optional<OICompiler::RelocResult> OICompiler::applyRelocs(
   return res;
 }
 
+int OICompiler::getLLVMVersionMajor() {
+  return LLVM_VERSION_MAJOR;
+}
+
 }  // namespace oi::detail

oi/OICompiler.h

@@ -183,6 +183,11 @@ class OICompiler {
   static std::optional<std::string> decodeInst(const std::vector<std::byte>&,
                                                uintptr_t);
 
+  /**
+   * @return the major version of LLVM this was compiled with
+   */
+  static int getLLVMVersionMajor();
+
  private:
   std::shared_ptr<SymbolService> symbols;
   Config config;

test/integration/CMakeLists.txt

@@ -59,6 +59,7 @@ target_link_libraries(integration_test_runner PRIVATE
   Boost::headers
   ${Boost_LIBRARIES}
   toml
+  oicore
 )
 target_compile_definitions(integration_test_runner PRIVATE
   TARGET_EXE_PATH="${CMAKE_CURRENT_BINARY_DIR}/integration_test_target"

test/integration/gen_tests.py

@@ -415,6 +415,13 @@ def generate_skip(case, specific):
     possibly_skip = ""
     skip_reason = case.get("skip", False)
     specific_skip_reason = case.get(f"{specific}_skip", False)
+
+    # Handle LLVM version constraints
+    min_llvm = case.get("min_llvm_version")
+    max_llvm = case.get("max_llvm_version")
+    skip_llvm = case.get("skip_llvm_version")
+
+    # Check if test should be skipped due to regular skip reasons
     if specific_skip_reason or skip_reason:
         possibly_skip += "  if (!run_skipped_tests) {\n"
         possibly_skip += "    GTEST_SKIP()"
@@ -425,6 +432,32 @@ def generate_skip(case, specific):
         possibly_skip += ";\n"
         possibly_skip += "  }\n"
 
+    # Check LLVM version constraints
+    if min_llvm is not None:
+        possibly_skip += f"  if (llvm_version_major < {min_llvm}) {{\n"
+        possibly_skip += f'    GTEST_SKIP() << "Requires LLVM {min_llvm} or newer, but running with LLVM " << llvm_version_major;\n'
+        possibly_skip += "  }\n"
+
+    if max_llvm is not None:
+        possibly_skip += f"  if (llvm_version_major > {max_llvm}) {{\n"
+        possibly_skip += f'    GTEST_SKIP() << "Requires LLVM {max_llvm} or older, but running with LLVM " << llvm_version_major;\n'
+        possibly_skip += "  }\n"
+
+    if skip_llvm is not None:
+        if isinstance(skip_llvm, list):
+            for version in skip_llvm:
+                possibly_skip += f"  if (llvm_version_major == {version}) {{\n"
+                possibly_skip += (
+                    f'    GTEST_SKIP() << "Test skipped for LLVM {version}";\n'
+                )
+                possibly_skip += "  }\n"
+        else:
+            possibly_skip += f"  if (llvm_version_major == {skip_llvm}) {{\n"
+            possibly_skip += (
+                f'    GTEST_SKIP() << "Test skipped for LLVM {skip_llvm}";\n'
+            )
+            possibly_skip += "  }\n"
+
     return possibly_skip
 
 
@@ -448,6 +481,7 @@ def gen_runner(output_runner_name, test_configs):
             "using ::testing::MatchesRegex;\n"
             "\n"
             "extern bool run_skipped_tests;\n"
+            "extern int llvm_version_major;\n"
         )
         for config in test_configs:
             add_tests(f, config)

test/integration/runner_common.cpp

@@ -12,6 +12,7 @@
 #include <string>
 #include <utility>
 
+#include "oi/OICompiler.h"
 #include "oi/OIOpts.h"
 #include "oi/support/Toml.h"
 
@@ -22,6 +23,7 @@ namespace bpt = boost::property_tree;
 namespace fs = std::filesystem;
 
 bool run_skipped_tests = false;
+int llvm_version_major = oi::detail::OICompiler::getLLVMVersionMajor();
 
 namespace {