1 files changed, 115 insertions, 0 deletions
diff --git a/llvm/lib/MC/ConstantPools.cpp b/llvm/lib/MC/ConstantPools.cpp
new file mode 100644
index 000000000000..8cba6b3281a5
--- /dev/null
+++ b/llvm/lib/MC/ConstantPools.cpp
@@ -0,0 +1,115 @@
+//===- ConstantPools.cpp - ConstantPool class -----------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ConstantPool and  AssemblerConstantPools classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/ConstantPools.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/Casting.h"
+
+using namespace llvm;
+
+//
+// ConstantPool implementation
+//
+// Emit the contents of the constant pool using the provided streamer.
+void ConstantPool::emitEntries(MCStreamer &Streamer) {
+  if (Entries.empty())
+    return;
+  Streamer.EmitDataRegion(MCDR_DataRegion);
+  for (const ConstantPoolEntry &Entry : Entries) {
+    Streamer.EmitCodeAlignment(Entry.Size); // align naturally
+    Streamer.EmitLabel(Entry.Label);
+    Streamer.EmitValue(Entry.Value, Entry.Size, Entry.Loc);
+  }
+  Streamer.EmitDataRegion(MCDR_DataRegionEnd);
+  Entries.clear();
+}
+
+const MCExpr *ConstantPool::addEntry(const MCExpr *Value, MCContext &Context,
+                                     unsigned Size, SMLoc Loc) {
+  const MCConstantExpr *C = dyn_cast<MCConstantExpr>(Value);
+
+  // Check if there is existing entry for the same constant. If so, reuse it.
+  auto Itr = C ? CachedEntries.find(C->getValue()) : CachedEntries.end();
+  if (Itr != CachedEntries.end())
+    return Itr->second;
+
+  MCSymbol *CPEntryLabel = Context.createTempSymbol();
+
+  Entries.push_back(ConstantPoolEntry(CPEntryLabel, Value, Size, Loc));
+  const auto SymRef = MCSymbolRefExpr::create(CPEntryLabel, Context);
+  if (C)
+    CachedEntries[C->getValue()] = SymRef;
+  return SymRef;
+}
+
+bool ConstantPool::empty() { return Entries.empty(); }
+
+void ConstantPool::clearCache() {
+  CachedEntries.clear();
+}
+
+//
+// AssemblerConstantPools implementation
+//
+ConstantPool *AssemblerConstantPools::getConstantPool(MCSection *Section) {
+  ConstantPoolMapTy::iterator CP = ConstantPools.find(Section);
+  if (CP == ConstantPools.end())
+    return nullptr;
+
+  return &CP->second;
+}
+
+ConstantPool &
+AssemblerConstantPools::getOrCreateConstantPool(MCSection *Section) {
+  return ConstantPools[Section];
+}
+
+static void emitConstantPool(MCStreamer &Streamer, MCSection *Section,
+                             ConstantPool &CP) {
+  if (!CP.empty()) {
+    Streamer.SwitchSection(Section);
+    CP.emitEntries(Streamer);
+  }
+}
+
+void AssemblerConstantPools::emitAll(MCStreamer &Streamer) {
+  // Dump contents of assembler constant pools.
+  for (auto &CPI : ConstantPools) {
+    MCSection *Section = CPI.first;
+    ConstantPool &CP = CPI.second;
+
+    emitConstantPool(Streamer, Section, CP);
+  }
+}
+
+void AssemblerConstantPools::emitForCurrentSection(MCStreamer &Streamer) {
+  MCSection *Section = Streamer.getCurrentSectionOnly();
+  if (ConstantPool *CP = getConstantPool(Section))
+    emitConstantPool(Streamer, Section, *CP);
+}
+
+void AssemblerConstantPools::clearCacheForCurrentSection(MCStreamer &Streamer) {
+  MCSection *Section = Streamer.getCurrentSectionOnly();
+  if (ConstantPool *CP = getConstantPool(Section))
+    CP->clearCache();
+}
+
+const MCExpr *AssemblerConstantPools::addEntry(MCStreamer &Streamer,
+                                               const MCExpr *Expr,
+                                               unsigned Size, SMLoc Loc) {
+  MCSection *Section = Streamer.getCurrentSectionOnly();
+  return getOrCreateConstantPool(Section).addEntry(Expr, Streamer.getContext(),
+                                                   Size, Loc);
+}