Delete old x86 validator.

src/trusted/validator/x86/ncval_reg_sfi/README

-This directory contains the code for the native client register based
-(R15) solution for x86-64 validation. R15 is used to convert 32-bit
-addresses to the corresponding 64-bit address for memory accesses.
-
-Note: Although the current builds generate 32-bit versions, they do
-not make any sense, since pointers are 32-bits in x86-32.
-
-
-nc_cpu_checks.{c,h}
-
-        Defines code that checks if the CPUID allows each
-        instruction. If not, it replaces the instruction with HALTs
-        during validation.
-
-nc_illegal.{c,h}
-
-        Defines code that checks each instruction to see if it meets
-        basic requirements for native client. This includes the
-        following checks:
-
-        - More than one (non-REX) prefix byte is not specified (we do
-          allow lock (f0) and DATA 16 (66) prefixes if the instruction
-          has been specified to accept both).
-
-        - The instruction has not been marked as illegal (see "Modeled
-          Instructions" below).
-
-        - The prefix/opcode sequence of the instruction has not been
-          marked as invalid (see "Modeled Instructions" below).
-
-        - The is not marked as a system instruction (see "Modeled
-          Instructions" below).
-
-        - Segment prefixes (except those used for jump prediction on
-          conditional jumps) are not allowed.
-
-        - The ADDR 16 (67) prefix has been used for the instruction,
-          but native client doesn't allow it (see "Modeled
-          Instructions" below).
-
-        - No more than one REX prefix has been specified for the
-          instruction.
-
-        - The REP (f3) prefix is not allowed for the instruction (see
-          "Modeled Instructions" below).
-
-        - The REPNE (f2) prefix is not allowed for the instruction
-          (see "Modeled Instructions" below).
-
-        - The DATA 16 (66) prefix is not allowed for the instruction
-          (see "Modeled Instructions" below).
-
-        - A prefix byte was not duplicated (we allow 66 to be
-          duplicated for special cases of the NOP instructions that
-          are commonly generated by compilers, see "Modeled
-          Instructions" for more information on these hard-coded
-          cases).
-
-        - Multiple, ambigious segment prefixes are not allowed for an
-          instruction.
-
-        - The REX prefix does not appear last in the sequence of
-          prefixes.
-
-nc_jumps.{c,h}
-
-        Defines code to check jump instructions. In general, explicit
-        jumps must jump to an instruction in the same segment if it is
-        explicitly specified using a constant. All other jumps should
-        be indirect and use a pre-approved pattern that adds R15 to a
-        corresponding 32-bit address.
-
-nc_memory_protect.{c,h}
-
-        Checks that memory references use an appropriate pattern that
-        converts a 32-bit data address (using R15) to a corresponding
-        64-bit memory reference.
-
-nc_opcode_histogram.{c,h}
-
-        Simple histogram tracker of the frequency that each opcode is
-        used.  Not needed to validate but provides useful test
-        information.
-
-nc_protect_base.{c,h}
-
-        Checks that the instruction doesn't improperly modify one of
-        the base registers RSP, RBP, and R15. Also checks LEA
-        instructions to see if they calculate an address of the form
-
-            [%reg+R15*1]
-
-        and put the results into an appropriate 32-bit register.
-
-ncvalidate_iter.c
-
-        Defines an iterator that iterates over the instructions in a
-        memory segment. Keeps track of the previous 2 instructions
-        during this iteration so that one can check multiple
-        instruction patterns. It also define
-
-ncvalidate_iter.h
-
-        Defines the API to the iterator defined in ncvalidate_iter.c.
-
-ncvalidate_iter_internal.h
-
-        Defines internal methods and data structures used to implement
-        the iterator defined in ncvalidate_iter.c
-
-ncvalidate_iter_verbose.c
-
-        Defines a verbose error reporter that works for the
-        instructions iterated over using the API methods in
-        ncvalidate_iter.h
-
-ncvalidate_utils.{c,h}
-
-        Defines various common checking routines for instructions.
-
-ncvalidate_registry.{c,h}
-
-        Defines a registry of validator checking methods, that get
-        applied to validate instruction.
-
-Modeled Instructions
---------------------
-
-Textual version(s) of the instructions understood by the validator can
-be found in the following files.
-
-   native_client/src/trusted/validator_x86/testdata/64/modeled_insts.txt
-
-      Defines the set of instructions understood by the (full)
-      decoder. This is the most human readable form of the generated
-      decoder tables used by the validator.
-
-   native_client/src/trusted/validator_x86/testdata/64/ncval_reg_sfi_modeled_insts.txt
-
-      Defines the set of (partial) isntructions understood by the
-      validator decoder. This file is the same as modeled_insts.txt
-      above except that it shows how the modeled instructions have
-      been simplified, based on the needs of the validator in this
-      directory. In particular, most instruction mnemonics are
-      simplified to a "don't care" name since the mnemonic name is not
-      needed by the validator. In addition, most implicit arguments of
-      the instruction are made explicit, and arguments that can't be
-      used to compute memory addresses have been removed.
-
-For more information on the contents of these files, see
-
-   native_client/src/trusted/validator/x86/decoder/README
-
-Pre/Post condition testing
---------------------------
-
-The code in this directory is set up to allow instructions to be
-validated individually.  When run in this mode, pre/post conditions
-are generated rather than looking accross instructions to verify the
-conditions. This is intentional, and is intended for testing multiple
-validators. In such contexts, the pre/post conditions define what must
-be checked by a compatible validator.
-
-To generate these condition tests, one must compile the source using
-the scons command:
-
-    .> ./scons --mode=opt-linux platform=x86-64 ncval_testing=1
-
-Note: --mode=opt-linux is not necessary. Any applicable mode will
-work.
-
-When native_client/src/trusted/validator_x86/ncval.c is compiled with
-the above scons command, the corresponding executable will generate
-pre/post conditions.
-
-Code to generate pre/post conditions is conditionalized in the source
-(under '#ifdef NCVAL_TESTING') so that it is only added when scons
-option ncval_testing=1 is defined.
-
-The default error reportor is used by the validator. This is done so
-that only pre/post conditions will be printed.  Hence, if you are to
-add debugging code within NCVAL_TESTING, be sure to not redirect the
-output to the validator's error reporter. Rather, redirect using calls
-to NaClLog or printf. To override this presumption and see other
-debugging messages, change the line
-
-        #define DEBUGGING 0
-
-in native_client/src/trusted/validator_x86/ncval.c to be
-
-        #define DEBUGGING 1
-
-This will cause the validator to use the verbose error reporter within
-ncval.
-
-To run unit tests for the pre/post conditions, run the following scons
-build command:
-
-    .> ./scons --mode=opt-linux platform=x86-64 ncval_testing=1 \
-         ncval_testing
-
-Note: To see how to test scons builds with ncval_testing=1, see
-native_client/src/trusted/validator_x86/build.scons and look for the
-text 'test_env.Bit('ncval_testing')'.
-
-Debugging
----------
-
-Many of the source files contain #define DEBUGGING flags. When
-DEBUGGING is set to 1, additional debugging print messages are
-compiled into the code. Unfortunately, by default, these message
-frequently call routines that are not compiled into corresponding
-executables (such as ncval and ncdis). To add the additional routines,
-edit file
-
-   native_client/site_scons/site_tools/library_deps.py
-
-For x86-32, edit lines
-
-            # When turning on the DEBUGGING flag in the x86-32 validator
-            # or decoder, add the following:
-            #'nc_opcode_modeling_verbose_x86_32',
-
-to
-
-            # When turning on the DEBUGGING flag in the x86-32 validator
-            # or decoder, add the following:
-            'nc_opcode_modeling_verbose_x86_32',
-
-For x86-64, edit lines
-
-            # When turning on the DEBUGGING flag in the x86-64 validator
-            # or decoder, add the following:
-            # 'nc_opcode_modeling_verbose_x86_64',
-
-to
-
-            # When turning on the DEBUGGING flag in the x86-64 validator
-            # or decoder, add the following:
-            'nc_opcode_modeling_verbose_x86_64',
-
-These changes will make sure that the corresponding print routines are
-added to the executables during link time.