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-rw-r--r--lib/AST/Interp/InterpStack.cpp78
1 files changed, 78 insertions, 0 deletions
diff --git a/lib/AST/Interp/InterpStack.cpp b/lib/AST/Interp/InterpStack.cpp
new file mode 100644
index 000000000000..5c803f3d9424
--- /dev/null
+++ b/lib/AST/Interp/InterpStack.cpp
@@ -0,0 +1,78 @@
+//===--- InterpStack.cpp - Stack implementation for the VM ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cassert>
+#include <cstdlib>
+#include "InterpStack.h"
+
+using namespace clang;
+using namespace clang::interp;
+
+InterpStack::~InterpStack() {
+ clear();
+}
+
+void InterpStack::clear() {
+ if (Chunk && Chunk->Next)
+ free(Chunk->Next);
+ if (Chunk)
+ free(Chunk);
+ Chunk = nullptr;
+ StackSize = 0;
+}
+
+void *InterpStack::grow(size_t Size) {
+ assert(Size < ChunkSize - sizeof(StackChunk) && "Object too large");
+
+ if (!Chunk || sizeof(StackChunk) + Chunk->size() + Size > ChunkSize) {
+ if (Chunk && Chunk->Next) {
+ Chunk = Chunk->Next;
+ } else {
+ StackChunk *Next = new (malloc(ChunkSize)) StackChunk(Chunk);
+ if (Chunk)
+ Chunk->Next = Next;
+ Chunk = Next;
+ }
+ }
+
+ auto *Object = reinterpret_cast<void *>(Chunk->End);
+ Chunk->End += Size;
+ StackSize += Size;
+ return Object;
+}
+
+void *InterpStack::peek(size_t Size) {
+ assert(Chunk && "Stack is empty!");
+
+ StackChunk *Ptr = Chunk;
+ while (Size > Ptr->size()) {
+ Size -= Ptr->size();
+ Ptr = Ptr->Prev;
+ assert(Ptr && "Offset too large");
+ }
+
+ return reinterpret_cast<void *>(Ptr->End - Size);
+}
+
+void InterpStack::shrink(size_t Size) {
+ assert(Chunk && "Chunk is empty!");
+
+ while (Size > Chunk->size()) {
+ Size -= Chunk->size();
+ if (Chunk->Next) {
+ free(Chunk->Next);
+ Chunk->Next = nullptr;
+ }
+ Chunk->End = Chunk->start();
+ Chunk = Chunk->Prev;
+ assert(Chunk && "Offset too large");
+ }
+
+ Chunk->End -= Size;
+ StackSize -= Size;
+}