Files
llvm/lldb/source/Symbol/PostfixExpression.cpp
Pavel Labath 88813103cd PostfixExpression: move parser out of NativePDB internals
Summary:
The postfix expressions in PDB and breakpad symbol files are similar
enough that they can be parsed by the same parser. This patch
generalizes the parser in the NativePDB plugin and moves it into the
PostfixExpression file created in the previous commit (r358976).

The generalization consists of treating any unrecognised token as a
"symbol" node (previously these would only be created for tokens
starting with "$", and other token would abort the parse). This is
needed because breakpad symbols can also contain ".cfa" tokens, which
refer to the frame's CFA.

The cosmetic changes include:
- using a factory function instead of a class for creating nodes (this
  is more generic as it allows the same BumpPtrAllocator to be used for
  other things too)
- using dedicated function for parsing operator tokens instead of a
  DenseMap (more efficient as we don't need to create the DenseMap every
  time).

Reviewers: amccarth, clayborg, JDevlieghere, aleksandr.urakov

Subscribers: jasonmolenda, lldb-commits, markmentovai, mgorny

Differential Revision: https://reviews.llvm.org/D61003

llvm-svn: 359073
2019-04-24 07:27:05 +00:00

83 lines
2.3 KiB
C++

//===-- PostfixExpression.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
//
//===----------------------------------------------------------------------===//
//
// This file implements support for postfix expressions found in several symbol
// file formats, and their conversion to DWARF.
//
//===----------------------------------------------------------------------===//
#include "lldb/Symbol/PostfixExpression.h"
#include "llvm/ADT/StringExtras.h"
using namespace lldb_private;
using namespace lldb_private::postfix;
static llvm::Optional<BinaryOpNode::OpType>
GetBinaryOpType(llvm::StringRef token) {
if (token.size() != 1)
return llvm::None;
switch (token[0]) {
case '@':
return BinaryOpNode::Align;
case '-':
return BinaryOpNode::Minus;
case '+':
return BinaryOpNode::Plus;
}
return llvm::None;
}
static llvm::Optional<UnaryOpNode::OpType>
GetUnaryOpType(llvm::StringRef token) {
if (token == "^")
return UnaryOpNode::Deref;
return llvm::None;
}
Node *postfix::Parse(llvm::StringRef expr, llvm::BumpPtrAllocator &alloc) {
llvm::SmallVector<Node *, 4> stack;
llvm::StringRef token;
while (std::tie(token, expr) = getToken(expr), !token.empty()) {
if (auto op_type = GetBinaryOpType(token)) {
// token is binary operator
if (stack.size() < 2)
return nullptr;
Node *right = stack.pop_back_val();
Node *left = stack.pop_back_val();
stack.push_back(MakeNode<BinaryOpNode>(alloc, *op_type, *left, *right));
continue;
}
if (auto op_type = GetUnaryOpType(token)) {
// token is unary operator
if (stack.empty())
return nullptr;
Node *operand = stack.pop_back_val();
stack.push_back(MakeNode<UnaryOpNode>(alloc, *op_type, *operand));
continue;
}
uint32_t value;
if (to_integer(token, value, 10)) {
// token is integer literal
stack.push_back(MakeNode<IntegerNode>(alloc, value));
continue;
}
stack.push_back(MakeNode<SymbolNode>(alloc, token));
}
if (stack.size() != 1)
return nullptr;
return stack.back();
}