The Tor Browser: comparison toolkit/crashreporter/google-breakpad/src/common/dwarf/cfi

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+:cbf89219ac45
+// -*- mode: C++ -*-
+// Copyright (c) 2010, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+// cfi_assembler.h: Define CFISection, a class for creating properly
+// (and improperly) formatted DWARF CFI data for unit tests.
+#ifndef PROCESSOR_CFI_ASSEMBLER_H_
+#define PROCESSOR_CFI_ASSEMBLER_H_
+#include <string>
+#include "common/dwarf/dwarf2enums.h"
+#include "common/test_assembler.h"
+#include "common/using_std_string.h"
+#include "google_breakpad/common/breakpad_types.h"
+namespace google_breakpad {
+using dwarf2reader::DwarfPointerEncoding;
+using google_breakpad::test_assembler::Endianness;
+using google_breakpad::test_assembler::Label;
+using google_breakpad::test_assembler::Section;
+class CFISection: public Section {
+public:
+// CFI augmentation strings beginning with 'z', defined by the
+// Linux/IA-64 C++ ABI, can specify interesting encodings for
+// addresses appearing in FDE headers and call frame instructions (and
+// for additional fields whose presence the augmentation string
+// specifies). In particular, pointers can be specified to be relative
+// to various base address: the start of the .text section, the
+// location holding the address itself, and so on. These allow the
+// frame data to be position-independent even when they live in
+// write-protected pages. These variants are specified at the
+// following two URLs:
+//
+// http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/dwarfext.html
+// http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
+//
+// CFISection leaves the production of well-formed 'z'-augmented CIEs and
+// FDEs to the user, but does provide EncodedPointer, to emit
+// properly-encoded addresses for a given pointer encoding.
+// EncodedPointer uses an instance of this structure to find the base
+// addresses it should use; you can establish a default for all encoded
+// pointers appended to this section with SetEncodedPointerBases.
+struct EncodedPointerBases {
+EncodedPointerBases() : cfi(), text(), data() { }
+// The starting address of this CFI section in memory, for
+// DW_EH_PE_pcrel. DW_EH_PE_pcrel pointers may only be used in data
+// that has is loaded into the program's address space.
+uint64_t cfi;
+// The starting address of this file's .text section, for DW_EH_PE_textrel.
+uint64_t text;
+// The starting address of this file's .got or .eh_frame_hdr section,
+// for DW_EH_PE_datarel.
+uint64_t data;
+};
+// Create a CFISection whose endianness is ENDIANNESS, and where
+// machine addresses are ADDRESS_SIZE bytes long. If EH_FRAME is
+// true, use the .eh_frame format, as described by the Linux
+// Standards Base Core Specification, instead of the DWARF CFI
+// format.
+CFISection(Endianness endianness, size_t address_size,
+bool eh_frame = false)
+: Section(endianness), address_size_(address_size), eh_frame_(eh_frame),
+pointer_encoding_(dwarf2reader::DW_EH_PE_absptr),
+encoded_pointer_bases_(), entry_length_(NULL), in_fde_(false) {
+// The 'start', 'Here', and 'Mark' members of a CFISection all refer
+// to section offsets.
+start() = 0;
+}
+// Return this CFISection's address size.
+size_t AddressSize() const { return address_size_; }
+// Return true if this CFISection uses the .eh_frame format, or
+// false if it contains ordinary DWARF CFI data.
+bool ContainsEHFrame() const { return eh_frame_; }
+// Use ENCODING for pointers in calls to FDEHeader and EncodedPointer.
+void SetPointerEncoding(DwarfPointerEncoding encoding) {
+pointer_encoding_ = encoding;
+}
+// Use the addresses in BASES as the base addresses for encoded
+// pointers in subsequent calls to FDEHeader or EncodedPointer.
+// This function makes a copy of BASES.
+void SetEncodedPointerBases(const EncodedPointerBases &bases) {
+encoded_pointer_bases_ = bases;
+}
+// Append a Common Information Entry header to this section with the
+// given values. If dwarf64 is true, use the 64-bit DWARF initial
+// length format for the CIE's initial length. Return a reference to
+// this section. You should call FinishEntry after writing the last
+// instruction for the CIE.
+//
+// Before calling this function, you will typically want to use Mark
+// or Here to make a label to pass to FDEHeader that refers to this
+// CIE's position in the section.
+CFISection &CIEHeader(uint64_t code_alignment_factor,
+int data_alignment_factor,
+unsigned return_address_register,
+uint8_t version = 3,
+const string &augmentation = "",
+bool dwarf64 = false);
+// Append a Frame Description Entry header to this section with the
+// given values. If dwarf64 is true, use the 64-bit DWARF initial
+// length format for the CIE's initial length. Return a reference to
+// this section. You should call FinishEntry after writing the last
+// instruction for the CIE.
+//
+// This function doesn't support entries that are longer than
+// 0xffffff00 bytes. (The "initial length" is always a 32-bit
+// value.) Nor does it support .debug_frame sections longer than
+// 0xffffff00 bytes.
+CFISection &FDEHeader(Label cie_pointer,
+uint64_t initial_location,
+uint64_t address_range,
+bool dwarf64 = false);
+// Note the current position as the end of the last CIE or FDE we
+// started, after padding with DW_CFA_nops for alignment. This
+// defines the label representing the entry's length, cited in the
+// entry's header. Return a reference to this section.
+CFISection &FinishEntry();
+// Append the contents of BLOCK as a DW_FORM_block value: an
+// unsigned LEB128 length, followed by that many bytes of data.
+CFISection &Block(const string &block) {
+ULEB128(block.size());
+Append(block);
+return *this;
+}
+// Append ADDRESS to this section, in the appropriate size and
+// endianness. Return a reference to this section.
+CFISection &Address(uint64_t address) {
+Section::Append(endianness(), address_size_, address);
+return *this;
+}
+CFISection &Address(Label address) {
+Section::Append(endianness(), address_size_, address);
+return *this;
+}
+// Append ADDRESS to this section, using ENCODING and BASES. ENCODING
+// defaults to this section's default encoding, established by
+// SetPointerEncoding. BASES defaults to this section's bases, set by
+// SetEncodedPointerBases. If the DW_EH_PE_indirect bit is set in the
+// encoding, assume that ADDRESS is where the true address is stored.
+// Return a reference to this section.
+//
+// (C++ doesn't let me use default arguments here, because I want to
+// refer to members of *this in the default argument expression.)
+CFISection &EncodedPointer(uint64_t address) {
+return EncodedPointer(address, pointer_encoding_, encoded_pointer_bases_);
+}
+CFISection &EncodedPointer(uint64_t address, DwarfPointerEncoding encoding) {
+return EncodedPointer(address, encoding, encoded_pointer_bases_);
+}
+CFISection &EncodedPointer(uint64_t address, DwarfPointerEncoding encoding,
+const EncodedPointerBases &bases);
+// Restate some member functions, to keep chaining working nicely.
+CFISection &Mark(Label *label)   { Section::Mark(label); return *this; }
+CFISection &D8(uint8_t v)       { Section::D8(v);       return *this; }
+CFISection &D16(uint16_t v)     { Section::D16(v);      return *this; }
+CFISection &D16(Label v)         { Section::D16(v);      return *this; }
+CFISection &D32(uint32_t v)     { Section::D32(v);      return *this; }
+CFISection &D32(const Label &v)  { Section::D32(v);      return *this; }
+CFISection &D64(uint64_t v)     { Section::D64(v);      return *this; }
+CFISection &D64(const Label &v)  { Section::D64(v);      return *this; }
+CFISection &LEB128(long long v)  { Section::LEB128(v);   return *this; }
+CFISection &ULEB128(uint64_t v) { Section::ULEB128(v);  return *this; }
+private:
+// A length value that we've appended to the section, but is not yet
+// known. LENGTH is the appended value; START is a label referring
+// to the start of the data whose length was cited.
+struct PendingLength {
+Label length;
+Label start;
+};
+// Constants used in CFI/.eh_frame data:
+// If the first four bytes of an "initial length" are this constant, then
+// the data uses the 64-bit DWARF format, and the length itself is the
+// subsequent eight bytes.
+static const uint32_t kDwarf64InitialLengthMarker = 0xffffffffU;
+// The CIE identifier for 32- and 64-bit DWARF CFI and .eh_frame data.
+static const uint32_t kDwarf32CIEIdentifier = ~(uint32_t)0;
+static const uint64_t kDwarf64CIEIdentifier = ~(uint64_t)0;
+static const uint32_t kEHFrame32CIEIdentifier = 0;
+static const uint64_t kEHFrame64CIEIdentifier = 0;
+// The size of a machine address for the data in this section.
+size_t address_size_;
+// If true, we are generating a Linux .eh_frame section, instead of
+// a standard DWARF .debug_frame section.
+bool eh_frame_;
+// The encoding to use for FDE pointers.
+DwarfPointerEncoding pointer_encoding_;
+// The base addresses to use when emitting encoded pointers.
+EncodedPointerBases encoded_pointer_bases_;
+// The length value for the current entry.
+//
+// Oddly, this must be dynamically allocated. Labels never get new
+// values; they only acquire constraints on the value they already
+// have, or assert if you assign them something incompatible. So
+// each header needs truly fresh Label objects to cite in their
+// headers and track their positions. The alternative is explicit
+// destructor invocation and a placement new. Ick.
+PendingLength *entry_length_;
+// True if we are currently emitting an FDE --- that is, we have
+// called FDEHeader but have not yet called FinishEntry.
+bool in_fde_;
+// If in_fde_ is true, this is its starting address. We use this for
+// emitting DW_EH_PE_funcrel pointers.
+uint64_t fde_start_address_;
+};
+}  // namespace google_breakpad
+#endif  // PROCESSOR_CFI_ASSEMBLER_H_

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comparison: toolkit/crashreporter/google-breakpad/src/common/dwarf/cfi_assembler.h

toolkit/crashreporter/google-breakpad/src/common/dwarf/cfi_assembler.h