1 files changed, 63 insertions, 8 deletions

diff --git a/clang/lib/CIR/CodeGen/CIRGenCleanup.cpp b/clang/lib/CIR/CodeGen/CIRGenCleanup.cpp
index be21ce9..b8663eb 100644
--- a/clang/lib/CIR/CodeGen/CIRGenCleanup.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenCleanup.cpp
@@ -16,6 +16,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "CIRGenCleanup.h"
 #include "CIRGenFunction.h"
 
 #include "clang/CIR/MissingFeatures.h"
@@ -33,6 +34,52 @@ using namespace clang::CIRGen;
 
 void EHScopeStack::Cleanup::anchor() {}
 
+/// Push an entry of the given size onto this protected-scope stack.
+char *EHScopeStack::allocate(size_t size) {
+  size = llvm::alignTo(size, ScopeStackAlignment);
+  if (!startOfBuffer) {
+    unsigned capacity = llvm::PowerOf2Ceil(std::max(size, 1024ul));
+    startOfBuffer = std::make_unique<char[]>(capacity);
+    startOfData = endOfBuffer = startOfBuffer.get() + capacity;
+  } else if (static_cast<size_t>(startOfData - startOfBuffer.get()) < size) {
+    unsigned currentCapacity = endOfBuffer - startOfBuffer.get();
+    unsigned usedCapacity =
+        currentCapacity - (startOfData - startOfBuffer.get());
+    unsigned requiredCapacity = usedCapacity + size;
+    // We know from the 'else if' condition that requiredCapacity is greater
+    // than currentCapacity.
+    unsigned newCapacity = llvm::PowerOf2Ceil(requiredCapacity);
+
+    std::unique_ptr<char[]> newStartOfBuffer =
+        std::make_unique<char[]>(newCapacity);
+    char *newEndOfBuffer = newStartOfBuffer.get() + newCapacity;
+    char *newStartOfData = newEndOfBuffer - usedCapacity;
+    memcpy(newStartOfData, startOfData, usedCapacity);
+    startOfBuffer.swap(newStartOfBuffer);
+    endOfBuffer = newEndOfBuffer;
+    startOfData = newStartOfData;
+  }
+
+  assert(startOfBuffer.get() + size <= startOfData);
+  startOfData -= size;
+  return startOfData;
+}
+
+void EHScopeStack::deallocate(size_t size) {
+  startOfData += llvm::alignTo(size, ScopeStackAlignment);
+}
+
+void *EHScopeStack::pushCleanup(CleanupKind kind, size_t size) {
+  char *buffer = allocate(size);
+
+  // When the full implementation is upstreamed, this will allocate
+  // extra memory for and construct a wrapper object that is used to
+  // manage the cleanup generation.
+  assert(!cir::MissingFeatures::ehCleanupScope());
+
+  return buffer;
+}
+
 static mlir::Block *getCurCleanupBlock(CIRGenFunction &cgf) {
   mlir::OpBuilder::InsertionGuard guard(cgf.getBuilder());
   mlir::Block *cleanup =
@@ -44,26 +91,34 @@ static mlir::Block *getCurCleanupBlock(CIRGenFunction &cgf) {
 /// current insertion point is threaded through the cleanup, as are
 /// any branch fixups on the cleanup.
 void CIRGenFunction::popCleanupBlock() {
-  assert(!ehStack.cleanupStack.empty() && "cleanup stack is empty!");
+  assert(!ehStack.empty() && "cleanup stack is empty!");
+
+  // The memory for the cleanup continues to be owned by the EHScopeStack
+  // allocator, so we just destroy the object rather than attempting to
+  // free it.
+  EHScopeStack::Cleanup &cleanup = *ehStack.begin();
+
+  // The eventual implementation here will use the EHCleanupScope helper class.
+  assert(!cir::MissingFeatures::ehCleanupScope());
+
   mlir::OpBuilder::InsertionGuard guard(builder);
-  std::unique_ptr<EHScopeStack::Cleanup> cleanup =
-      ehStack.cleanupStack.pop_back_val();
 
   assert(!cir::MissingFeatures::ehCleanupFlags());
   mlir::Block *cleanupEntry = getCurCleanupBlock(*this);
   builder.setInsertionPointToEnd(cleanupEntry);
-  cleanup->emit(*this);
+  cleanup.emit(*this);
+
+  ehStack.deallocate(cleanup.getSize());
 }
 
 /// Pops cleanup blocks until the given savepoint is reached.
-void CIRGenFunction::popCleanupBlocks(size_t oldCleanupStackDepth) {
+void CIRGenFunction::popCleanupBlocks(
+    EHScopeStack::stable_iterator oldCleanupStackDepth) {
   assert(!cir::MissingFeatures::ehstackBranches());
 
-  assert(ehStack.getStackDepth() >= oldCleanupStackDepth);
-
   // Pop cleanup blocks until we reach the base stack depth for the
   // current scope.
-  while (ehStack.getStackDepth() > oldCleanupStackDepth) {
+  while (ehStack.stable_begin() != oldCleanupStackDepth) {
     popCleanupBlock();
   }
 }