[KeyInstr] Remove LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS CMake flag

OCHyams · OCHyams · commit 672dd58702be · 2025-08-08T15:55:35.000+01:00
The CMake flag has been on by default for a month without any issues.

This makes the feature support in LLVM unconditional (but does not enable the
feature by default).
diff --git a/clang/test/CMakeLists.txt b/clang/test/CMakeLists.txt
@@ -26,7 +26,6 @@ llvm_canonicalize_cmake_booleans(
   PPC_LINUX_DEFAULT_IEEELONGDOUBLE
   LLVM_TOOL_LLVM_DRIVER_BUILD
   LLVM_INCLUDE_SPIRV_TOOLS_TESTS
-  LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS
   )
 
 # Run tests requiring Z3 headers only if LLVM was built with Z3
diff --git a/clang/test/DebugInfo/KeyInstructions/lit.local.cfg b/clang/test/DebugInfo/KeyInstructions/lit.local.cfg
diff --git a/clang/test/lit.site.cfg.py.in b/clang/test/lit.site.cfg.py.in
@@ -46,7 +46,6 @@ config.ppc_linux_default_ieeelongdouble = @PPC_LINUX_DEFAULT_IEEELONGDOUBLE@
 config.have_llvm_driver = @LLVM_TOOL_LLVM_DRIVER_BUILD@
 config.spirv_tools_tests = @LLVM_INCLUDE_SPIRV_TOOLS_TESTS@
 config.substitutions.append(("%llvm-version-major", "@LLVM_VERSION_MAJOR@"))
-config.has_key_instructions = @LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
@@ -588,9 +588,6 @@ set(LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING "DISABLED" CACHE STRING
   "Enhance Debugify's line number coverage tracking; enabling this is ABI-breaking. Can be DISABLED, COVERAGE, or COVERAGE_AND_ORIGIN.")
 set_property(CACHE LLVM_ENABLE_DEBUGLOC_COVERAGE_TRACKING PROPERTY STRINGS DISABLED COVERAGE COVERAGE_AND_ORIGIN)
 
-option(LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS
-  "Add additional fields to DILocations to support Key Instructions" ON)
-
 set(WINDOWS_PREFER_FORWARD_SLASH_DEFAULT OFF)
 if (MINGW)
   # Cygwin doesn't identify itself as Windows, and thus gets path::Style::posix
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -212,10 +212,6 @@ endif()
 # LLVM_ENABLE_DEBUGLOC_TRACKING_COVERAGE (non-cached) is expected to be
 # 1 or 0 here, assuming referenced in #cmakedefine01.
 
-if(LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS)
-  add_compile_definitions(EXPERIMENTAL_KEY_INSTRUCTIONS)
-endif()
-
 if( LLVM_REVERSE_ITERATION )
   set( LLVM_ENABLE_REVERSE_ITERATION 1 )
 endif()
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -2506,10 +2506,8 @@ class DISubprogram : public DILocalScope {
 class DILocation : public MDNode {
   friend class LLVMContextImpl;
   friend class MDNode;
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
   uint64_t AtomGroup : 61;
   uint64_t AtomRank : 3;
-#endif
 
   DILocation(LLVMContext &C, StorageType Storage, unsigned Line,
              unsigned Column, uint64_t AtomGroup, uint8_t AtomRank,
@@ -2540,18 +2538,10 @@ class DILocation : public MDNode {
 
 public:
   uint64_t getAtomGroup() const {
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
     return AtomGroup;
-#else
-    return 0;
-#endif
   }
   uint8_t getAtomRank() const {
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
     return AtomRank;
-#else
-    return 0;
-#endif
   }
 
   const DILocation *getWithoutAtom() const {
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -57,15 +57,9 @@ DebugVariable::DebugVariable(const DbgVariableRecord *DVR)
 DILocation::DILocation(LLVMContext &C, StorageType Storage, unsigned Line,
                        unsigned Column, uint64_t AtomGroup, uint8_t AtomRank,
                        ArrayRef<Metadata *> MDs, bool ImplicitCode)
-    : MDNode(C, DILocationKind, Storage, MDs)
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
-      ,
-      AtomGroup(AtomGroup), AtomRank(AtomRank)
-#endif
-{
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
+    : MDNode(C, DILocationKind, Storage, MDs), AtomGroup(AtomGroup),
+      AtomRank(AtomRank) {
   assert(AtomRank <= 7 && "AtomRank number should fit in 3 bits");
-#endif
   if (AtomGroup)
     C.updateDILocationAtomGroupWaterline(AtomGroup + 1);
 
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
@@ -312,29 +312,22 @@ template <> struct MDNodeKeyImpl<MDTuple> : MDNodeOpsKey {
 template <> struct MDNodeKeyImpl<DILocation> {
   Metadata *Scope;
   Metadata *InlinedAt;
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
   uint64_t AtomGroup : 61;
   uint64_t AtomRank : 3;
-#endif
   unsigned Line;
   uint16_t Column;
   bool ImplicitCode;
 
   MDNodeKeyImpl(unsigned Line, uint16_t Column, Metadata *Scope,
                 Metadata *InlinedAt, bool ImplicitCode, uint64_t AtomGroup,
                 uint8_t AtomRank)
-      : Scope(Scope), InlinedAt(InlinedAt),
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
-        AtomGroup(AtomGroup), AtomRank(AtomRank),
-#endif
-        Line(Line), Column(Column), ImplicitCode(ImplicitCode) {
-  }
+      : Scope(Scope), InlinedAt(InlinedAt), AtomGroup(AtomGroup),
+        AtomRank(AtomRank), Line(Line), Column(Column),
+        ImplicitCode(ImplicitCode) {}
 
   MDNodeKeyImpl(const DILocation *L)
       : Scope(L->getRawScope()), InlinedAt(L->getRawInlinedAt()),
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
         AtomGroup(L->getAtomGroup()), AtomRank(L->getAtomRank()),
-#endif
         Line(L->getLine()), Column(L->getColumn()),
         ImplicitCode(L->isImplicitCode()) {
   }
@@ -343,16 +336,11 @@ template <> struct MDNodeKeyImpl<DILocation> {
     return Line == RHS->getLine() && Column == RHS->getColumn() &&
            Scope == RHS->getRawScope() && InlinedAt == RHS->getRawInlinedAt() &&
            ImplicitCode == RHS->isImplicitCode()
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
            && AtomGroup == RHS->getAtomGroup() &&
            AtomRank == RHS->getAtomRank();
-#else
-        ;
-#endif
   }
 
   unsigned getHashValue() const {
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
     // Hashing AtomGroup and AtomRank substantially impacts performance whether
     // Key Instructions is enabled or not. We can't detect whether it's enabled
     // here cheaply; avoiding hashing zero values is a good approximation. This
@@ -363,7 +351,6 @@ template <> struct MDNodeKeyImpl<DILocation> {
     if (AtomGroup || AtomRank)
       return hash_combine(Line, Column, Scope, InlinedAt, ImplicitCode,
                           AtomGroup, (uint8_t)AtomRank);
-#endif
     return hash_combine(Line, Column, Scope, InlinedAt, ImplicitCode);
   }
 };
diff --git a/llvm/test/CMakeLists.txt b/llvm/test/CMakeLists.txt
@@ -30,7 +30,6 @@ llvm_canonicalize_cmake_booleans(
   LLVM_INCLUDE_SPIRV_TOOLS_TESTS
   LLVM_APPEND_VC_REV
   LLVM_HAS_LOGF128
-  LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS
   )
 
 configure_lit_site_cfg(
diff --git a/llvm/test/DebugInfo/KeyInstructions/debugify.ll b/llvm/test/DebugInfo/KeyInstructions/debugify.ll
@@ -1,10 +1,7 @@
 ; RUN: opt -passes=debugify --debugify-atoms -S -o - < %s \
 ; RUN: | FileCheck %s
 
-;; Mirrors llvm/test/DebugInfo/debugify.ll. Split out here because the
-;; test is only supported if LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS is enabled
-;; (which is a condition for running this test directory). Once the conditional
-;; compilation of the feature is removed this can be merged into the original.
+;; Mirrors llvm/test/DebugInfo/debugify.ll
 
 ; CHECK-LABEL: define void @foo
 define void @foo() {
diff --git a/llvm/test/DebugInfo/KeyInstructions/lit.local.cfg b/llvm/test/DebugInfo/KeyInstructions/lit.local.cfg
diff --git a/llvm/test/lit.site.cfg.py.in b/llvm/test/lit.site.cfg.py.in
@@ -66,7 +66,6 @@ config.spirv_tools_tests = @LLVM_INCLUDE_SPIRV_TOOLS_TESTS@
 config.have_vc_rev = @LLVM_APPEND_VC_REV@
 config.force_vc_rev = "@LLVM_FORCE_VC_REVISION@"
 config.has_logf128 = @LLVM_HAS_LOGF128@
-config.has_key_instructions = @LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
diff --git a/llvm/unittests/IR/BasicBlockDbgInfoTest.cpp b/llvm/unittests/IR/BasicBlockDbgInfoTest.cpp
@@ -189,11 +189,7 @@ TEST(BasicBlockDbgInfoTest, DropSourceAtomOnSplit) {
     ASSERT_TRUE(After);
     const DebugLoc &OrigTerminatorDL = After->getTerminator()->getDebugLoc();
     ASSERT_TRUE(OrigTerminatorDL);
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
     EXPECT_EQ(OrigTerminatorDL->getAtomGroup(), 1u);
-#else
-    EXPECT_EQ(OrigTerminatorDL->getAtomGroup(), 0u);
-#endif
   }
 
   // Test splitBasicBlock.
@@ -204,11 +200,7 @@ TEST(BasicBlockDbgInfoTest, DropSourceAtomOnSplit) {
 
     const DebugLoc &OrigTerminatorDL = After->getTerminator()->getDebugLoc();
     ASSERT_TRUE(OrigTerminatorDL);
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
     EXPECT_EQ(OrigTerminatorDL->getAtomGroup(), 1u);
-#else
-    EXPECT_EQ(OrigTerminatorDL->getAtomGroup(), 0u);
-#endif
 
     BasicBlock *Before = After->getSinglePredecessor();
     ASSERT_TRUE(Before);
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
@@ -1470,17 +1470,10 @@ TEST_F(DILocationTest, Merge) {
     PickMergedSourceLocations = false;
   }
 
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
 #define EXPECT_ATOM(Loc, Group, Rank)                                          \
   EXPECT_EQ(Group, M->getAtomGroup());                                         \
   EXPECT_EQ(Rank, M->getAtomRank());
-#else
-#define EXPECT_ATOM(Loc, Group, Rank)                                          \
-  EXPECT_EQ(0u, M->getAtomGroup());                                            \
-  EXPECT_EQ(0u, M->getAtomRank());                                             \
-  (void)Group;                                                                 \
-  (void)Rank;
-#endif
+
   // Identical, including source atom numbers.
   {
     auto *A = DILocation::get(Context, 2, 7, N, nullptr, false, /*AtomGroup*/ 1,
@@ -1753,15 +1746,8 @@ TEST_F(DILocationTest, KeyInstructions) {
   EXPECT_EQ(Context.pImpl->NextAtomGroup, 1u);
   DILocation *A1 =
       DILocation::get(Context, 1, 0, getSubprogram(), nullptr, false, 1, 2);
-  // The group is only applied to the DILocation if we've built LLVM with
-  // EXPERIMENTAL_KEY_INSTRUCTIONS.
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
   EXPECT_EQ(A1->getAtomGroup(), 1u);
   EXPECT_EQ(A1->getAtomRank(), 2u);
-#else
-  EXPECT_EQ(A1->getAtomGroup(), 0u);
-  EXPECT_EQ(A1->getAtomRank(), 0u);
-#endif
 
   // Group number 1 has been "used" so next available is 2.
   EXPECT_EQ(Context.pImpl->NextAtomGroup, 2u);
diff --git a/llvm/unittests/Transforms/Utils/CloningTest.cpp b/llvm/unittests/Transforms/Utils/CloningTest.cpp
@@ -1203,13 +1203,9 @@ TEST_F(CloneInstruction, cloneKeyInstructions) {
 
   ASSERT_FALSE(verifyModule(*M, &errs()));
 
-#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
 #define EXPECT_ATOM(Inst, G)                                                   \
   EXPECT_TRUE(Inst->getDebugLoc());                                            \
   EXPECT_EQ(Inst->getDebugLoc()->getAtomGroup(), uint64_t(G));
-#else
-#define EXPECT_ATOM(Inst, G) (void)Inst;
-#endif
 
   Function *F = M->getFunction("test");
   BasicBlock *BB = &*F->begin();
diff --git a/llvm/utils/gn/secondary/clang/test/BUILD.gn b/llvm/utils/gn/secondary/clang/test/BUILD.gn
@@ -60,7 +60,6 @@ write_lit_config("lit_site_cfg") {
     "CLANG_VENDOR_UTI=org.llvm.clang",
     "ENABLE_BACKTRACES=1",
     "ENABLE_SHARED=0",
-    "LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS=0",
     "LLVM_EXTERNAL_LIT=",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
     "LLVM_INCLUDE_SPIRV_TOOLS_TESTS=0",
diff --git a/llvm/utils/gn/secondary/llvm/test/BUILD.gn b/llvm/utils/gn/secondary/llvm/test/BUILD.gn
@@ -65,7 +65,6 @@ write_lit_config("lit_site_cfg") {
     "LLVM_ENABLE_FFI=0",
     "LLVM_ENABLE_HTTPLIB=0",
     "LLVM_ENABLE_PROFCHECK=0",
-    "LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS=0",
     "LLVM_FORCE_VC_REVISION=",
     "LLVM_HAS_LOGF128=0",
     "LLVM_HAVE_OPT_VIEWER_MODULES=0",
diff --git a/utils/bazel/llvm-project-overlay/llvm/config.bzl b/utils/bazel/llvm-project-overlay/llvm/config.bzl
@@ -113,7 +113,6 @@ llvm_config_defines = os_defines + builtin_thread_pointer + select({
     "LLVM_VERSION_PATCH={}".format(LLVM_VERSION_PATCH),
     r'LLVM_VERSION_STRING=\"{}\"'.format(PACKAGE_VERSION),
     # Set globally in HandleLLVMOptions.cmake
-    "EXPERIMENTAL_KEY_INSTRUCTIONS",
     # These shouldn't be needed by the C++11 standard, but are for some
     # platforms (e.g. glibc < 2.18. See
     # https://sourceware.org/bugzilla/show_bug.cgi?id=15366). These are also

Original file line number	Diff line number	Diff line change
`@@ -26,7 +26,6 @@ llvm_canonicalize_cmake_booleans(`
`26`	`26`	`PPC_LINUX_DEFAULT_IEEELONGDOUBLE`
`27`	`27`	`LLVM_TOOL_LLVM_DRIVER_BUILD`
`28`	`28`	`LLVM_INCLUDE_SPIRV_TOOLS_TESTS`
`29`		`- LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS`
`30`	`29`	`)`
`31`	`30`
`32`	`31`	`# Run tests requiring Z3 headers only if LLVM was built with Z3`
Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,6 @@ llvm_canonicalize_cmake_booleans(`
`30`	`30`	`LLVM_INCLUDE_SPIRV_TOOLS_TESTS`
`31`	`31`	`LLVM_APPEND_VC_REV`
`32`	`32`	`LLVM_HAS_LOGF128`
`33`		`- LLVM_EXPERIMENTAL_KEY_INSTRUCTIONS`
`34`	`33`	`)`
`35`	`34`
`36`	`35`	`configure_lit_site_cfg(`