1 files changed, 137 insertions, 0 deletions
diff --git a/source/Plugins/SymbolFile/NativePDB/PdbFPOProgramToDWARFExpression.cpp b/source/Plugins/SymbolFile/NativePDB/PdbFPOProgramToDWARFExpression.cpp
new file mode 100644
index 000000000000..79dd010ff311
--- /dev/null
+++ b/source/Plugins/SymbolFile/NativePDB/PdbFPOProgramToDWARFExpression.cpp
@@ -0,0 +1,137 @@
+//===-- PdbFPOProgramToDWARFExpression.cpp ----------------------*- 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 "PdbFPOProgramToDWARFExpression.h"
+#include "CodeViewRegisterMapping.h"
+
+#include "lldb/Core/StreamBuffer.h"
+#include "lldb/Symbol/PostfixExpression.h"
+#include "lldb/Utility/LLDBAssert.h"
+#include "lldb/Utility/Stream.h"
+#include "llvm/ADT/DenseMap.h"
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/DebugInfo/CodeView/CodeView.h"
+#include "llvm/DebugInfo/CodeView/EnumTables.h"
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::postfix;
+
+static uint32_t ResolveLLDBRegisterNum(llvm::StringRef reg_name, llvm::Triple::ArchType arch_type) {
+  // lookup register name to get lldb register number
+  llvm::codeview::CPUType cpu_type;
+  switch (arch_type) {
+    case llvm::Triple::ArchType::aarch64:
+      cpu_type = llvm::codeview::CPUType::ARM64;
+      break;
+
+    default:
+      cpu_type = llvm::codeview::CPUType::X64;
+      break;
+  }
+
+  llvm::ArrayRef<llvm::EnumEntry<uint16_t>> register_names =
+      llvm::codeview::getRegisterNames(cpu_type);
+  auto it = llvm::find_if(
+      register_names,
+      [&reg_name](const llvm::EnumEntry<uint16_t> &register_entry) {
+        return reg_name.compare_lower(register_entry.Name) == 0;
+      });
+
+  if (it == register_names.end())
+    return LLDB_INVALID_REGNUM;
+
+  auto reg_id = static_cast<llvm::codeview::RegisterId>(it->Value);
+  return npdb::GetLLDBRegisterNumber(arch_type, reg_id);
+}
+
+static bool ParseFPOSingleAssignmentProgram(llvm::StringRef program,
+                                            llvm::BumpPtrAllocator &alloc,
+                                            llvm::StringRef &register_name,
+                                            Node *&ast) {
+  // lvalue of assignment is always first token
+  // rvalue program goes next
+  std::tie(register_name, program) = getToken(program);
+  if (register_name.empty())
+    return false;
+
+  ast = Parse(program, alloc);
+  return ast != nullptr;
+}
+
+static Node *ParseFPOProgram(llvm::StringRef program,
+                             llvm::StringRef register_name,
+                             llvm::Triple::ArchType arch_type,
+                             llvm::BumpPtrAllocator &alloc) {
+  llvm::DenseMap<llvm::StringRef, Node *> dependent_programs;
+
+  size_t cur = 0;
+  while (true) {
+    size_t assign_index = program.find('=', cur);
+    if (assign_index == llvm::StringRef::npos) {
+      llvm::StringRef tail = program.slice(cur, llvm::StringRef::npos);
+      if (!tail.trim().empty()) {
+        // missing assign operator
+        return nullptr;
+      }
+      break;
+    }
+    llvm::StringRef assignment_program = program.slice(cur, assign_index);
+
+    llvm::StringRef lvalue_name;
+    Node *rvalue_ast = nullptr;
+    if (!ParseFPOSingleAssignmentProgram(assignment_program, alloc, lvalue_name,
+                                         rvalue_ast)) {
+      return nullptr;
+    }
+
+    lldbassert(rvalue_ast);
+
+    // Emplace valid dependent subtrees to make target assignment independent
+    // from predecessors. Resolve all other SymbolNodes as registers.
+    bool success =
+        ResolveSymbols(rvalue_ast, [&](SymbolNode &symbol) -> Node * {
+          if (Node *node = dependent_programs.lookup(symbol.GetName()))
+            return node;
+          uint32_t reg_num =
+              ResolveLLDBRegisterNum(symbol.GetName().drop_front(1), arch_type);
+
+          if (reg_num == LLDB_INVALID_REGNUM)
+            return nullptr;
+
+          return MakeNode<RegisterNode>(alloc, reg_num);
+        });
+    if (!success)
+      return nullptr;
+
+    if (lvalue_name == register_name) {
+      // found target assignment program - no need to parse further
+      return rvalue_ast;
+    }
+
+    dependent_programs[lvalue_name] = rvalue_ast;
+    cur = assign_index + 1;
+  }
+
+  return nullptr;
+}
+
+bool lldb_private::npdb::TranslateFPOProgramToDWARFExpression(
+    llvm::StringRef program, llvm::StringRef register_name,
+    llvm::Triple::ArchType arch_type, Stream &stream) {
+  llvm::BumpPtrAllocator node_alloc;
+  Node *target_program =
+      ParseFPOProgram(program, register_name, arch_type, node_alloc);
+  if (target_program == nullptr) {
+    return false;
+  }
+
+  ToDWARF(*target_program, stream);
+  return true;
+}