[CodeGen] Add MachineFrameInfo

Model stable frame indices, stack object kinds, tombstones, lifetimes, and frozen layouts. Validate owned frame references in the builder and verifier, and remap complete frame state during MachineFunction cloning.

1 files changed, 156 insertions, 0 deletions

diff --git a/backend/unittests/CodeGen/MachineFrameInfoTest.cpp b/backend/unittests/CodeGen/MachineFrameInfoTest.cpp
new file mode 100644
index 0000000..7368815
--- /dev/null
+++ b/backend/unittests/CodeGen/MachineFrameInfoTest.cpp
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "rcc/CodeGen/MachineFrameInfo.h"
+
+#include <cstdint>
+#include <iostream>
+#include <string_view>
+
+namespace {
+
+class TestContext final {
+public:
+  void expect(bool Condition, std::string_view Message) {
+    if (Condition)
+      return;
+    std::cerr << Message << '\n';
+    ++FailureCount;
+  }
+
+  [[nodiscard]] int result() const noexcept {
+    return FailureCount == 0 ? 0 : 1;
+  }
+
+private:
+  int FailureCount = 0;
+};
+
+[[nodiscard]] rcc::StackObjectDesc fixedObject(std::uint64_t Size, std::uint64_t Align) {
+  rcc::StackObjectDesc Description;
+  Description.Size = Size;
+  Description.Align = *rcc::Alignment::create(Align);
+  return Description;
+}
+
+void testObjectLifecycle(TestContext &Context) {
+  rcc::MachineFrameInfo Frame;
+
+  auto LocalDescription = fixedObject(8, 8);
+  LocalDescription.IsAliased = true;
+  LocalDescription.AddressTaken = true;
+  LocalDescription.Lifetime.push_back(
+      {rcc::MachineInstrStableID::fromValue(3), rcc::MachineInstrStableID::fromValue(7)});
+  auto Local = Frame.createObject(LocalDescription);
+
+  auto FixedDescription = fixedObject(16, 16);
+  FixedDescription.Kind = rcc::StackObjectKind::FixedABI;
+  FixedDescription.Offset = -32;
+  auto Fixed = Frame.createObject(FixedDescription);
+
+  auto SpillDescription = fixedObject(8, 8);
+  SpillDescription.Kind = rcc::StackObjectKind::SpillSlot;
+  auto Spill = Frame.createObject(SpillDescription);
+
+  rcc::StackObjectDesc VariableDescription;
+  VariableDescription.Kind = rcc::StackObjectKind::VariableSized;
+  VariableDescription.Align = *rcc::Alignment::create(32);
+  auto Variable = Frame.createObject(VariableDescription);
+
+  Context.expect(Local && Fixed && Spill && Variable, "valid stack object kinds must be created");
+  if (!Local || !Fixed || !Spill || !Variable)
+    return;
+
+  Context.expect(Local->value() == 0 && Fixed->value() == 1 && Spill->value() == 2 &&
+                     Variable->value() == 3 && Frame.liveObjectCount() == 4,
+                 "frame indices must be monotonic table identities");
+  Context.expect(Frame.object(*Fixed)->isFixed() && Frame.object(*Spill)->isSpill() &&
+                     Frame.object(*Variable)->isVariableSized(),
+                 "stack object semantic categories must be derived exactly");
+
+  Context.expect(Frame.setObjectOffset(*Local, -8).has_value() &&
+                     Frame.setObjectOffset(*Spill, -16).has_value() &&
+                     Frame.markObjectDead(*Spill).has_value(),
+                 "live stack objects must support controlled pre-freeze updates");
+  Context.expect(Frame.object(*Spill)->description()->IsDead,
+                 "dead stack object state must remain explicit");
+
+  Context.expect(Frame.eraseObject(*Fixed).has_value() && Frame.object(*Fixed) == nullptr &&
+                     Frame.liveObjectCount() == 3,
+                 "erasing a stack object must leave an inaccessible tombstone");
+  auto Replacement = Frame.createObject(fixedObject(4, 4));
+  Context.expect(Replacement && Replacement->value() == 4,
+                 "erased frame indices must never be reused");
+  if (!Replacement)
+    return;
+  Context.expect(Frame.setObjectOffset(*Replacement, -24).has_value(),
+                 "replacement stack object must accept a final offset");
+
+  Context.expect(Frame.setMaxCallFrameSize(24).has_value() &&
+                     Frame.freeze(64, *rcc::Alignment::create(16)).has_value() &&
+                     Frame.isFrozen() && Frame.staticStackSize() == 64 &&
+                     Frame.stackAlignment().bytes() == 16 && Frame.maxCallFrameSize() == 24 &&
+                     Frame.verify().has_value(),
+                 "complete frame layout must freeze atomically");
+
+  Context.expect(!Frame.createObject(fixedObject(8, 8)) && !Frame.setObjectOffset(*Local, -40) &&
+                     !Frame.eraseObject(*Local) && !Frame.setMaxCallFrameSize(32) &&
+                     !Frame.freeze(64, *rcc::Alignment::create(16)),
+                 "frozen frames must reject every semantic mutation");
+}
+
+void testInvalidDescriptions(TestContext &Context) {
+  rcc::MachineFrameInfo Frame;
+
+  rcc::StackObjectDesc MissingSize;
+  Context.expect(!Frame.createObject(MissingSize),
+                 "fixed-size stack object must reject a missing size");
+
+  auto ZeroSize = fixedObject(0, 1);
+  Context.expect(!Frame.createObject(ZeroSize), "fixed-size stack object must reject zero size");
+
+  rcc::StackObjectDesc InvalidVariable;
+  InvalidVariable.Kind = rcc::StackObjectKind::DynamicAlloca;
+  InvalidVariable.Size = 8;
+  Context.expect(!Frame.createObject(InvalidVariable),
+                 "variable-sized stack object must reject a fixed size");
+
+  auto MissingFixedOffset = fixedObject(8, 8);
+  MissingFixedOffset.Kind = rcc::StackObjectKind::FixedABI;
+  Context.expect(!Frame.createObject(MissingFixedOffset),
+                 "fixed ABI stack object must require an offset");
+
+  auto InvalidTarget = fixedObject(8, 8);
+  InvalidTarget.Kind = rcc::StackObjectKind::Target;
+  Context.expect(!Frame.createObject(InvalidTarget),
+                 "target stack object must carry target identity");
+
+  auto InvalidLifetime = fixedObject(8, 8);
+  InvalidLifetime.Lifetime.push_back(
+      {rcc::MachineInstrStableID::fromValue(4), rcc::MachineInstrStableID::fromValue(4)});
+  Context.expect(!Frame.createObject(InvalidLifetime),
+                 "stack object lifetime must reject equal boundaries");
+
+  Context.expect(!rcc::StackID::targetStack(4), "target stack IDs must not overlap built-in IDs");
+  auto TargetStack = rcc::StackID::targetStack(256);
+  auto Target = fixedObject(8, 8);
+  Target.Kind = rcc::StackObjectKind::Target;
+  if (TargetStack)
+    Target.Stack = *TargetStack;
+  auto TargetIndex = Frame.createObject(Target);
+  Context.expect(TargetStack && TargetIndex,
+                 "target stack identity must admit target stack objects");
+
+  auto Unresolved = Frame.createObject(fixedObject(8, 8));
+  Context.expect(Unresolved && !Frame.freeze(16, *rcc::Alignment::create(8)) && !Frame.isFrozen() &&
+                     !Frame.staticStackSize() && Frame.verify().has_value(),
+                 "failed frame freeze must not mutate frame state");
+}
+
+} // namespace
+
+int main() {
+  TestContext Context;
+  testObjectLifecycle(Context);
+  testInvalidDescriptions(Context);
+  return Context.result();
+}