scripts/parameter_validation_generator.py

#!/usr/bin/python3 -i
#
# Copyright (c) 2015-2016 The Khronos Group Inc.
# Copyright (c) 2015-2016 Valve Corporation
# Copyright (c) 2015-2016 LunarG, Inc.
# Copyright (c) 2015-2016 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Author: Dustin Graves <dustin@lunarg.com>

import os,re,sys
import xml.etree.ElementTree as etree
from generator import *
from collections import namedtuple


# ParamCheckerGeneratorOptions - subclass of GeneratorOptions.
#
# Adds options used by ParamCheckerOutputGenerator object during Parameter
# validation layer generation.
#
# Additional members
#   prefixText - list of strings to prefix generated header with
#     (usually a copyright statement + calling convention macros).
#   protectFile - True if multiple inclusion protection should be
#     generated (based on the filename) around the entire header.
#   protectFeature - True if #ifndef..#endif protection should be
#     generated around a feature interface in the header file.
#   genFuncPointers - True if function pointer typedefs should be
#     generated
#   protectProto - If conditional protection should be generated
#     around prototype declarations, set to either '#ifdef'
#     to require opt-in (#ifdef protectProtoStr) or '#ifndef'
#     to require opt-out (#ifndef protectProtoStr). Otherwise
#     set to None.
#   protectProtoStr - #ifdef/#ifndef symbol to use around prototype
#     declarations, if protectProto is set
#   apicall - string to use for the function declaration prefix,
#     such as APICALL on Windows.
#   apientry - string to use for the calling convention macro,
#     in typedefs, such as APIENTRY.
#   apientryp - string to use for the calling convention macro
#     in function pointer typedefs, such as APIENTRYP.
#   indentFuncProto - True if prototype declarations should put each
#     parameter on a separate line
#   indentFuncPointer - True if typedefed function pointers should put each
#     parameter on a separate line
#   alignFuncParam - if nonzero and parameters are being put on a
#     separate line, align parameter names at the specified column
class ParamCheckerGeneratorOptions(GeneratorOptions):
    def __init__(self,
                 filename = None,
                 directory = '.',
                 apiname = None,
                 profile = None,
                 versions = '.*',
                 emitversions = '.*',
                 defaultExtensions = None,
                 addExtensions = None,
                 removeExtensions = None,
                 sortProcedure = regSortFeatures,
                 prefixText = "",
                 genFuncPointers = True,
                 protectFile = True,
                 protectFeature = True,
                 protectProto = None,
                 protectProtoStr = None,
                 apicall = '',
                 apientry = '',
                 apientryp = '',
                 indentFuncProto = True,
                 indentFuncPointer = False,
                 alignFuncParam = 0):
        GeneratorOptions.__init__(self, filename, directory, apiname, profile,
                                  versions, emitversions, defaultExtensions,
                                  addExtensions, removeExtensions, sortProcedure)
        self.prefixText      = prefixText
        self.genFuncPointers = genFuncPointers
        self.protectFile     = protectFile
        self.protectFeature  = protectFeature
        self.protectProto    = protectProto
        self.protectProtoStr = protectProtoStr
        self.apicall         = apicall
        self.apientry        = apientry
        self.apientryp       = apientryp
        self.indentFuncProto = indentFuncProto
        self.indentFuncPointer = indentFuncPointer
        self.alignFuncParam  = alignFuncParam

# ParamCheckerOutputGenerator - subclass of OutputGenerator.
# Generates param checker layer code.
#
# ---- methods ----
# ParamCheckerOutputGenerator(errFile, warnFile, diagFile) - args as for
#   OutputGenerator. Defines additional internal state.
# ---- methods overriding base class ----
# beginFile(genOpts)
# endFile()
# beginFeature(interface, emit)
# endFeature()
# genType(typeinfo,name)
# genStruct(typeinfo,name)
# genGroup(groupinfo,name)
# genEnum(enuminfo, name)
# genCmd(cmdinfo)
class ParamCheckerOutputGenerator(OutputGenerator):
    """Generate ParamChecker code based on XML element attributes"""
    # This is an ordered list of sections in the header file.
    ALL_SECTIONS = ['command']
    def __init__(self,
                 errFile = sys.stderr,
                 warnFile = sys.stderr,
                 diagFile = sys.stdout):
        OutputGenerator.__init__(self, errFile, warnFile, diagFile)
        self.INDENT_SPACES = 4
        # Commands to ignore
        self.blacklist = [
            'vkGetInstanceProcAddr',
            'vkGetDeviceProcAddr',
            'vkEnumerateInstanceLayerProperties',
            'vkEnumerateInstanceExtensionsProperties',
            'vkEnumerateDeviceLayerProperties',
            'vkEnumerateDeviceExtensionsProperties',
            'vkCreateDebugReportCallbackEXT',
            'vkDebugReportMessageEXT']
        # Validation conditions for some special case struct members that are conditionally validated
        self.structMemberValidationConditions = { 'VkPipelineColorBlendStateCreateInfo' : { 'logicOp' : '{}logicOpEnable == VK_TRUE' } }
        # Header version
        self.headerVersion = None
        # Internal state - accumulators for different inner block text
        self.sections = dict([(section, []) for section in self.ALL_SECTIONS])
        self.structNames = []                             # List of Vulkan struct typenames
        self.stypes = []                                  # Values from the VkStructureType enumeration
        self.structTypes = dict()                         # Map of Vulkan struct typename to required VkStructureType
        self.handleTypes = set()                          # Set of handle type names
        self.commands = []                                # List of CommandData records for all Vulkan commands
        self.structMembers = []                           # List of StructMemberData records for all Vulkan structs
        self.validatedStructs = dict()                    # Map of structs type names to generated validation code for that struct type
        self.enumRanges = dict()                          # Map of enum name to BEGIN/END range values
        self.flags = set()                                # Map of flags typenames
        self.flagBits = dict()                            # Map of flag bits typename to list of values
        self.newFlags = set()                             # Map of flags typenames /defined in the current feature/
        # Named tuples to store struct and command data
        self.StructType = namedtuple('StructType', ['name', 'value'])
        self.CommandParam = namedtuple('CommandParam', ['type', 'name', 'ispointer', 'isstaticarray', 'isbool', 'israngedenum',
                                                        'isconst', 'isoptional', 'iscount', 'noautovalidity', 'len', 'extstructs',
                                                        'condition', 'cdecl'])
        self.CommandData = namedtuple('CommandData', ['name', 'params', 'cdecl'])
        self.StructMemberData = namedtuple('StructMemberData', ['name', 'members'])
    #
    def incIndent(self, indent):
        inc = ' ' * self.INDENT_SPACES
        if indent:
            return indent + inc
        return inc
    #
    def decIndent(self, indent):
        if indent and (len(indent) > self.INDENT_SPACES):
            return indent[:-self.INDENT_SPACES]
        return ''
    #
    def beginFile(self, genOpts):
        OutputGenerator.beginFile(self, genOpts)
        # C-specific
        #
        # User-supplied prefix text, if any (list of strings)
        if (genOpts.prefixText):
            for s in genOpts.prefixText:
                write(s, file=self.outFile)
        #
        # Multiple inclusion protection & C++ wrappers.
        if (genOpts.protectFile and self.genOpts.filename):
            headerSym = re.sub('\.h', '_H', os.path.basename(self.genOpts.filename)).upper()
            write('#ifndef', headerSym, file=self.outFile)
            write('#define', headerSym, '1', file=self.outFile)
            self.newline()
        #
        # Headers
        write('#include <string>', file=self.outFile)
        self.newline()
        write('#include "vulkan/vulkan.h"', file=self.outFile)
        write('#include "vk_layer_extension_utils.h"', file=self.outFile)
        write('#include "parameter_validation_utils.h"', file=self.outFile)
        #
        # Macros
        self.newline()
        write('#ifndef UNUSED_PARAMETER', file=self.outFile)
        write('#define UNUSED_PARAMETER(x) (void)(x)', file=self.outFile)
        write('#endif // UNUSED_PARAMETER', file=self.outFile)
        #
        # Namespace
        self.newline()
        write('namespace parameter_validation {', file = self.outFile)
    def endFile(self):
        # C-specific
        self.newline()
        # Namespace
        write('} // namespace parameter_validation', file = self.outFile)
        # Finish C++ wrapper and multiple inclusion protection
        if (self.genOpts.protectFile and self.genOpts.filename):
            self.newline()
            write('#endif', file=self.outFile)
        # Finish processing in superclass
        OutputGenerator.endFile(self)
    def beginFeature(self, interface, emit):
        # Start processing in superclass
        OutputGenerator.beginFeature(self, interface, emit)
        # C-specific
        # Accumulate includes, defines, types, enums, function pointer typedefs,
        # end function prototypes separately for this feature. They're only
        # printed in endFeature().
        self.headerVersion = None
        self.sections = dict([(section, []) for section in self.ALL_SECTIONS])
        self.structNames = []
        self.stypes = []
        self.structTypes = dict()
        self.commands = []
        self.structMembers = []
        self.validatedStructs = dict()
        self.newFlags = set()
    def endFeature(self):
        # C-specific
        # Actually write the interface to the output file.
        if (self.emit):
            self.newline()
            # If type declarations are needed by other features based on
            # this one, it may be necessary to suppress the ExtraProtect,
            # or move it below the 'for section...' loop.
            if (self.featureExtraProtect != None):
                write('#ifdef', self.featureExtraProtect, file=self.outFile)
            # Generate the struct member checking code from the captured data
            self.processStructMemberData()
            # Generate the command parameter checking code from the captured data
            self.processCmdData()
            # Write the declaration for the HeaderVersion
            if self.headerVersion:
                write('const uint32_t GeneratedHeaderVersion = {};'.format(self.headerVersion), file=self.outFile)
                self.newline()
            # Write the declarations for the VkFlags values combining all flag bits
            for flag in sorted(self.newFlags):
                flagBits = flag.replace('Flags', 'FlagBits')
                if flagBits in self.flagBits:
                    bits = self.flagBits[flagBits]
                    decl = 'const {} All{} = {}'.format(flag, flagBits, bits[0])
                    for bit in bits[1:]:
                        decl += '|' + bit
                    decl += ';'
                    write(decl, file=self.outFile)
            self.newline()
            # Write the parameter validation code to the file
            if (self.sections['command']):
                if (self.genOpts.protectProto):
                    write(self.genOpts.protectProto,
                          self.genOpts.protectProtoStr, file=self.outFile)
                write('\n'.join(self.sections['command']), end=u'', file=self.outFile)
            if (self.featureExtraProtect != None):
                write('#endif /*', self.featureExtraProtect, '*/', file=self.outFile)
            else:
                self.newline()
        # Finish processing in superclass
        OutputGenerator.endFeature(self)
    #
    # Append a definition to the specified section
    def appendSection(self, section, text):
        # self.sections[section].append('SECTION: ' + section + '\n')
        self.sections[section].append(text)
    #
    # Type generation
    def genType(self, typeinfo, name):
        OutputGenerator.genType(self, typeinfo, name)
        typeElem = typeinfo.elem
        # If the type is a struct type, traverse the imbedded <member> tags
        # generating a structure. Otherwise, emit the tag text.
        category = typeElem.get('category')
        if (category == 'struct' or category == 'union'):
            self.structNames.append(name)
            self.genStruct(typeinfo, name)
        elif (category == 'handle'):
            self.handleTypes.add(name)
        elif (category == 'bitmask'):
            self.flags.add(name)
            self.newFlags.add(name)
        elif (category == 'define'):
            if name == 'VK_HEADER_VERSION':
                nameElem = typeElem.find('name')
                self.headerVersion = noneStr(nameElem.tail).strip()
    #
    # Struct parameter check generation.
    # This is a special case of the <type> tag where the contents are
    # interpreted as a set of <member> tags instead of freeform C
    # C type declarations. The <member> tags are just like <param>
    # tags - they are a declaration of a struct or union member.
    # Only simple member declarations are supported (no nested
    # structs etc.)
    def genStruct(self, typeinfo, typeName):
        OutputGenerator.genStruct(self, typeinfo, typeName)
        conditions = self.structMemberValidationConditions[typeName] if typeName in self.structMemberValidationConditions else None
        members = typeinfo.elem.findall('.//member')
        #
        # Iterate over members once to get length parameters for arrays
        lens = set()
        for member in members:
            len = self.getLen(member)
            if len:
                lens.add(len)
        #
        # Generate member info
        membersInfo = []
        for member in members:
            # Get the member's type and name
            info = self.getTypeNameTuple(member)
            type = info[0]
            name = info[1]
            stypeValue = ''
            cdecl = self.makeCParamDecl(member, 0)
            # Process VkStructureType
            if type == 'VkStructureType':
                # Extract the required struct type value from the comments
                # embedded in the original text defining the 'typeinfo' element
                rawXml = etree.tostring(typeinfo.elem).decode('ascii')
                result = re.search(r'VK_STRUCTURE_TYPE_\w+', rawXml)
                if result:
                    value = result.group(0)
                else:
                    value = self.genVkStructureType(typeName)
                # Store the required type value
                self.structTypes[typeName] = self.StructType(name=name, value=value)
            #
            # Store pointer/array/string info
            # Check for parameter name in lens set
            iscount = False
            if name in lens:
                iscount = True
            # The pNext members are not tagged as optional, but are treated as
            # optional for parameter NULL checks.  Static array members
            # are also treated as optional to skip NULL pointer validation, as
            # they won't be NULL.
            isstaticarray = self.paramIsStaticArray(member)
            isoptional = False
            if self.paramIsOptional(member) or (name == 'pNext') or (isstaticarray):
                isoptional = True
            membersInfo.append(self.CommandParam(type=type, name=name,
                                                ispointer=self.paramIsPointer(member),
                                                isstaticarray=isstaticarray,
                                                isbool=True if type == 'VkBool32' else False,
                                                israngedenum=True if type in self.enumRanges else False,
                                                isconst=True if 'const' in cdecl else False,
                                                isoptional=isoptional,
                                                iscount=iscount,
                                                noautovalidity=True if member.attrib.get('noautovalidity') is not None else False,
                                                len=self.getLen(member),
                                                extstructs=member.attrib.get('validextensionstructs') if name == 'pNext' else None,
                                                condition=conditions[name] if conditions and name in conditions else None,
                                                cdecl=cdecl))
        self.structMembers.append(self.StructMemberData(name=typeName, members=membersInfo))
    #
    # Capture group (e.g. C "enum" type) info to be used for
    # param check code generation.
    # These are concatenated together with other types.
    def genGroup(self, groupinfo, groupName):
        OutputGenerator.genGroup(self, groupinfo, groupName)
        groupElem = groupinfo.elem
        #
        # Store the sType values
        if groupName == 'VkStructureType':
            for elem in groupElem.findall('enum'):
                self.stypes.append(elem.get('name'))
        elif 'FlagBits' in groupName:
            bits = []
            for elem in groupElem.findall('enum'):
                bits.append(elem.get('name'))
            if bits:
                self.flagBits[groupName] = bits
        else:
            # Determine if begin/end ranges are needed (we don't do this for VkStructureType, which has a more finely grained check)
            expandName = re.sub(r'([0-9a-z_])([A-Z0-9][^A-Z0-9]?)',r'\1_\2',groupName).upper()
            expandPrefix = expandName
            expandSuffix = ''
            expandSuffixMatch = re.search(r'[A-Z][A-Z]+$',groupName)
            if expandSuffixMatch:
                expandSuffix = '_' + expandSuffixMatch.group()
                # Strip off the suffix from the prefix
                expandPrefix = expandName.rsplit(expandSuffix, 1)[0]
            isEnum = ('FLAG_BITS' not in expandPrefix)
            if isEnum:
                self.enumRanges[groupName] = (expandPrefix + '_BEGIN_RANGE' + expandSuffix, expandPrefix + '_END_RANGE' + expandSuffix)
    #
    # Capture command parameter info to be used for param
    # check code generation.
    def genCmd(self, cmdinfo, name):
        OutputGenerator.genCmd(self, cmdinfo, name)
        if name not in self.blacklist:
            params = cmdinfo.elem.findall('param')
            # Get list of array lengths
            lens = set()
            for param in params:
                len = self.getLen(param)
                if len:
                    lens.add(len)
            # Get param info
            paramsInfo = []
            for param in params:
                paramInfo = self.getTypeNameTuple(param)
                cdecl = self.makeCParamDecl(param, 0)
                # Check for parameter name in lens set
                iscount = False
                if paramInfo[1] in lens:
                    iscount = True
                paramsInfo.append(self.CommandParam(type=paramInfo[0], name=paramInfo[1],
                                                    ispointer=self.paramIsPointer(param),
                                                    isstaticarray=self.paramIsStaticArray(param),
                                                    isbool=True if paramInfo[0] == 'VkBool32' else False,
                                                    israngedenum=True if paramInfo[0] in self.enumRanges else False,
                                                    isconst=True if 'const' in cdecl else False,
                                                    isoptional=self.paramIsOptional(param),
                                                    iscount=iscount,
                                                    noautovalidity=True if param.attrib.get('noautovalidity') is not None else False,
                                                    len=self.getLen(param),
                                                    extstructs=None,
                                                    condition=None,
                                                    cdecl=cdecl))
            self.commands.append(self.CommandData(name=name, params=paramsInfo, cdecl=self.makeCDecls(cmdinfo.elem)[0]))
    #
    # Check if the parameter passed in is a pointer
    def paramIsPointer(self, param):
        ispointer = 0
        paramtype = param.find('type')
        if (paramtype.tail is not None) and ('*' in paramtype.tail):
            ispointer = paramtype.tail.count('*')
        elif paramtype.text[:4] == 'PFN_':
            # Treat function pointer typedefs as a pointer to a single value
            ispointer = 1
        return ispointer
    #
    # Check if the parameter passed in is a static array
    def paramIsStaticArray(self, param):
        isstaticarray = 0
        paramname = param.find('name')
        if (paramname.tail is not None) and ('[' in paramname.tail):
            isstaticarray = paramname.tail.count('[')
        return isstaticarray
    #
    # Check if the parameter passed in is optional
    # Returns a list of Boolean values for comma separated len attributes (len='false,true')
    def paramIsOptional(self, param):
        # See if the handle is optional
        isoptional = False
        # Simple, if it's optional, return true
        optString = param.attrib.get('optional')
        if optString:
            if optString == 'true':
                isoptional = True
            elif ',' in optString:
                opts = []
                for opt in optString.split(','):
                    val = opt.strip()
                    if val == 'true':
                        opts.append(True)
                    elif val == 'false':
                        opts.append(False)
                    else:
                        print('Unrecognized len attribute value',val)
                isoptional = opts
        return isoptional
    #
    # Check if the handle passed in is optional
    # Uses the same logic as ValidityOutputGenerator.isHandleOptional
    def isHandleOptional(self, param, lenParam):
        # Simple, if it's optional, return true
        if param.isoptional:
            return True
        # If no validity is being generated, it usually means that validity is complex and not absolute, so let's say yes.
        if param.noautovalidity:
            return True
        # If the parameter is an array and we haven't already returned, find out if any of the len parameters are optional
        if lenParam and lenParam.isoptional:
            return True
        return False
    #
    # Generate a VkStructureType based on a structure typename
    def genVkStructureType(self, typename):
        # Add underscore between lowercase then uppercase
        value = re.sub('([a-z0-9])([A-Z])', r'\1_\2', typename)
        value = value.replace('D3_D12', 'D3D12')
        value = value.replace('Device_IDProp', 'Device_ID_Prop')
        # Change to uppercase
        value = value.upper()
        # Add STRUCTURE_TYPE_
        return re.sub('VK_', 'VK_STRUCTURE_TYPE_', value)
    #
    # Get the cached VkStructureType value for the specified struct typename, or generate a VkStructureType
    # value assuming the struct is defined by a different feature
    def getStructType(self, typename):
        value = None
        if typename in self.structTypes:
            value = self.structTypes[typename].value
        else:
            value = self.genVkStructureType(typename)
            self.logMsg('diag', 'ParameterValidation: Generating {} for {} structure type that was not defined by the current feature'.format(value, typename))
        return value
    #
    # Retrieve the value of the len tag
    def getLen(self, param):
        result = None
        len = param.attrib.get('len')
        if len and len != 'null-terminated':
            # For string arrays, 'len' can look like 'count,null-terminated',
            # indicating that we have a null terminated array of strings.  We
            # strip the null-terminated from the 'len' field and only return
            # the parameter specifying the string count
            if 'null-terminated' in len:
                result = len.split(',')[0]
            else:
                result = len
            result = str(result).replace('::', '->')
        return result
    #
    # Retrieve the type and name for a parameter
    def getTypeNameTuple(self, param):
        type = ''
        name = ''
        for elem in param:
            if elem.tag == 'type':
                type = noneStr(elem.text)
            elif elem.tag == 'name':
                name = noneStr(elem.text)
        return (type, name)
    #
    # Find a named parameter in a parameter list
    def getParamByName(self, params, name):
        for param in params:
            if param.name == name:
                return param
        return None
    #
    # Extract length values from latexmath.  Currently an inflexible solution that looks for specific
    # patterns that are found in vk.xml.  Will need to be updated when new patterns are introduced.
    def parseLateXMath(self, source):
        name = 'ERROR'
        decoratedName = 'ERROR'
        if 'mathit' in source:
            # Matches expressions similar to 'latexmath:[$\lceil{\mathit{rasterizationSamples} \over 32}\rceil$]'
            match = re.match(r'latexmath\s*\:\s*\[\s*\$\\l(\w+)\s*\{\s*\\mathit\s*\{\s*(\w+)\s*\}\s*\\over\s*(\d+)\s*\}\s*\\r(\w+)\$\s*\]', source)
            if not match or match.group(1) != match.group(4):
                raise 'Unrecognized latexmath expression'
            name = match.group(2)
            decoratedName = '{}({}/{})'.format(*match.group(1, 2, 3))
        else:
            # Matches expressions similar to 'latexmath : [$dataSize \over 4$]'
            match = re.match(r'latexmath\s*\:\s*\[\s*\$\s*(\w+)\s*\\over\s*(\d+)\s*\$\s*\]', source)
            name = match.group(1)
            decoratedName = '{}/{}'.format(*match.group(1, 2))
        return name, decoratedName
    #
    # Get the length paramater record for the specified parameter name
    def getLenParam(self, params, name):
        lenParam = None
        if name:
            if '->' in name:
                # The count is obtained by dereferencing a member of a struct parameter
                lenParam = self.CommandParam(name=name, iscount=True, ispointer=False, isbool=False, israngedenum=False, isconst=False,
                                             isstaticarray=None, isoptional=False, type=None, noautovalidity=False, len=None, extstructs=None,
                                             condition=None, cdecl=None)
            elif 'latexmath' in name:
                lenName, decoratedName = self.parseLateXMath(name)
                lenParam = self.getParamByName(params, lenName)
                # TODO: Zero-check the result produced by the equation?
                # Copy the stored len parameter entry and overwrite the name with the processed latexmath equation
                #param = self.getParamByName(params, lenName)
                #lenParam = self.CommandParam(name=decoratedName, iscount=param.iscount, ispointer=param.ispointer,
                #                             isoptional=param.isoptional, type=param.type, len=param.len,
                #                             isstaticarray=param.isstaticarray, extstructs=param.extstructs,
                #                             noautovalidity=True, condition=None, cdecl=param.cdecl)
            else:
                lenParam = self.getParamByName(params, name)
        return lenParam
    #
    # Convert a vulkan.h command declaration into a parameter_validation.h definition
    def getCmdDef(self, cmd):
        #
        # Strip the trailing ';' and split into individual lines
        lines = cmd.cdecl[:-1].split('\n')
        # Replace Vulkan prototype
        lines[0] = 'static bool parameter_validation_' + cmd.name + '('
        # Replace the first argument with debug_report_data, when the first
        # argument is a handle (not vkCreateInstance)
        reportData = '    debug_report_data*'.ljust(self.genOpts.alignFuncParam) + 'report_data,'
        if cmd.name != 'vkCreateInstance':
            lines[1] = reportData
        else:
            lines.insert(1, reportData)
        return '\n'.join(lines)
    #
    # Generate the code to check for a NULL dereference before calling the
    # validation function
    def genCheckedLengthCall(self, name, exprs):
        count = name.count('->')
        if count:
            checkedExpr = []
            localIndent = ''
            elements = name.split('->')
            # Open the if expression blocks
            for i in range(0, count):
                checkedExpr.append(localIndent + 'if ({} != NULL) {{\n'.format('->'.join(elements[0:i+1])))
                localIndent = self.incIndent(localIndent)
            # Add the validation expression
            for expr in exprs:
                checkedExpr.append(localIndent + expr)
            # Close the if blocks
            for i in range(0, count):
                localIndent = self.decIndent(localIndent)
                checkedExpr.append(localIndent + '}\n')
            return [checkedExpr]
        # No if statements were required
        return exprs
    #
    # Generate code to check for a specific condition before executing validation code
    def genConditionalCall(self, prefix, condition, exprs):
        checkedExpr = []
        localIndent = ''
        formattedCondition = condition.format(prefix)
        checkedExpr.append(localIndent + 'if ({})\n'.format(formattedCondition))
        checkedExpr.append(localIndent + '{\n')
        localIndent = self.incIndent(localIndent)
        for expr in exprs:
            checkedExpr.append(localIndent + expr)
        localIndent = self.decIndent(localIndent)
        checkedExpr.append(localIndent + '}\n')
        return [checkedExpr]
    #
    # Generate the sType check string
    def makeStructTypeCheck(self, prefix, value, lenValue, valueRequired, lenValueRequired, lenPtrRequired, funcPrintName, lenPrintName, valuePrintName, postProcSpec):
        checkExpr = []
        stype = self.structTypes[value.type]
        if lenValue:
            # This is an array with a pointer to a count value
            if lenValue.ispointer:
                # When the length parameter is a pointer, there is an extra Boolean parameter in the function call to indicate if it is required
                checkExpr.append('skipCall |= validate_struct_type_array(report_data, "{}", {ppp}"{ldn}"{pps}, {ppp}"{dn}"{pps}, "{sv}", {pf}{ln}, {pf}{vn}, {sv}, {}, {}, {});\n'.format(
                    funcPrintName, lenPtrRequired, lenValueRequired, valueRequired, ln=lenValue.name, ldn=lenPrintName, dn=valuePrintName, vn=value.name, sv=stype.value, pf=prefix, **postProcSpec))
            # This is an array with an integer count value
            else:
                checkExpr.append('skipCall |= validate_struct_type_array(report_data, "{}", {ppp}"{ldn}"{pps}, {ppp}"{dn}"{pps}, "{sv}", {pf}{ln}, {pf}{vn}, {sv}, {}, {});\n'.format(
                    funcPrintName, lenValueRequired, valueRequired, ln=lenValue.name, ldn=lenPrintName, dn=valuePrintName, vn=value.name, sv=stype.value, pf=prefix, **postProcSpec))
        # This is an individual struct
        else:
            checkExpr.append('skipCall |= validate_struct_type(report_data, "{}", {ppp}"{}"{pps}, "{sv}", {}{vn}, {sv}, {});\n'.format(
                funcPrintName, valuePrintName, prefix, valueRequired, vn=value.name, sv=stype.value, **postProcSpec))
        return checkExpr
    #
    # Generate the handle check string
    def makeHandleCheck(self, prefix, value, lenValue, valueRequired, lenValueRequired, funcPrintName, lenPrintName, valuePrintName, postProcSpec):
        checkExpr = []
        if lenValue:
            if lenValue.ispointer:
                # This is assumed to be an output array with a pointer to a count value
                raise('Unsupported parameter validation case: Output handle array elements are not NULL checked')
            else:
                # This is an array with an integer count value
                checkExpr.append('skipCall |= validate_handle_array(report_data, "{}", {ppp}"{ldn}"{pps}, {ppp}"{dn}"{pps}, {pf}{ln}, {pf}{vn}, {}, {});\n'.format(
                    funcPrintName, lenValueRequired, valueRequired, ln=lenValue.name, ldn=lenPrintName, dn=valuePrintName, vn=value.name, pf=prefix, **postProcSpec))
        else:
            # This is assumed to be an output handle pointer
            raise('Unsupported parameter validation case: Output handles are not NULL checked')
        return checkExpr
    #
    # Generate check string for an array of VkFlags values
    def makeFlagsArrayCheck(self, prefix, value, lenValue, valueRequired, lenValueRequired, funcPrintName, lenPrintName, valuePrintName, postProcSpec):
        checkExpr = []
        flagBitsName = value.type.replace('Flags', 'FlagBits')
        if not flagBitsName in self.flagBits:
            raise('Unsupported parameter validation case: array of reserved VkFlags')
        else:
            allFlags = 'All' + flagBitsName
            checkExpr.append('skipCall |= validate_flags_array(report_data, "{}", {ppp}"{}"{pps}, {ppp}"{}"{pps}, "{}", {}, {pf}{}, {pf}{}, {}, {});\n'.format(funcPrintName, lenPrintName, valuePrintName, flagBitsName, allFlags, lenValue.name, value.name, lenValueRequired, valueRequired, pf=prefix, **postProcSpec))
        return checkExpr
    #
    # Generate pNext check string
    def makeStructNextCheck(self, prefix, value, funcPrintName, valuePrintName, postProcSpec):
        checkExpr = []
        # Generate an array of acceptable VkStructureType values for pNext
        extStructCount = 0
        extStructVar = 'NULL'
        extStructNames = 'NULL'
        if value.extstructs:
            structs = value.extstructs.split(',')
            checkExpr.append('const VkStructureType allowedStructs[] = {' + ', '.join([self.getStructType(s) for s in structs]) + '};\n')
            extStructCount = 'ARRAY_SIZE(allowedStructs)'
            extStructVar = 'allowedStructs'
            extStructNames = '"' + ', '.join(structs) + '"'
        checkExpr.append('skipCall |= validate_struct_pnext(report_data, "{}", {ppp}"{}"{pps}, {}, {}{}, {}, {}, GeneratedHeaderVersion);\n'.format(
            funcPrintName, valuePrintName, extStructNames, prefix, value.name, extStructCount, extStructVar, **postProcSpec))
        return checkExpr
    #
    # Generate the pointer check string
    def makePointerCheck(self, prefix, value, lenValue, valueRequired, lenValueRequired, lenPtrRequired, funcPrintName, lenPrintName, valuePrintName, postProcSpec):
        checkExpr = []
        if lenValue:
            # This is an array with a pointer to a count value
            if lenValue.ispointer:
                # If count and array parameters are optional, there will be no validation
                if valueRequired == 'true' or lenPtrRequired == 'true' or lenValueRequired == 'true':
                    # When the length parameter is a pointer, there is an extra Boolean parameter in the function call to indicate if it is required
                    checkExpr.append('skipCall |= validate_array(report_data, "{}", {ppp}"{ldn}"{pps}, {ppp}"{dn}"{pps}, {pf}{ln}, {pf}{vn}, {}, {}, {});\n'.format(
                        funcPrintName, lenPtrRequired, lenValueRequired, valueRequired, ln=lenValue.name, ldn=lenPrintName, dn=valuePrintName, vn=value.name, pf=prefix, **postProcSpec))
            # This is an array with an integer count value
            else:
                # If count and array parameters are optional, there will be no validation
                if valueRequired == 'true' or lenValueRequired == 'true':
                    # Arrays of strings receive special processing
                    validationFuncName = 'validate_array' if value.type != 'char' else 'validate_string_array'
                    checkExpr.append('skipCall |= {}(report_data, "{}", {ppp}"{ldn}"{pps}, {ppp}"{dn}"{pps}, {pf}{ln}, {pf}{vn}, {}, {});\n'.format(
                        validationFuncName, funcPrintName, lenValueRequired, valueRequired, ln=lenValue.name, ldn=lenPrintName, dn=valuePrintName, vn=value.name, pf=prefix, **postProcSpec))
            if checkExpr:
                if lenValue and ('->' in lenValue.name):
                    # Add checks to ensure the validation call does not dereference a NULL pointer to obtain the count
                    checkExpr = self.genCheckedLengthCall(lenValue.name, checkExpr)
        # This is an individual struct that is not allowed to be NULL
        elif not value.isoptional:
            # Function pointers need a reinterpret_cast to void*
            if value.type[:4] == 'PFN_':
                checkExpr.append('skipCall |= validate_required_pointer(report_data, "{}", {ppp}"{}"{pps}, reinterpret_cast<const void*>({}{}));\n'.format(funcPrintName, valuePrintName, prefix, value.name, **postProcSpec))
            else:
                checkExpr.append('skipCall |= validate_required_pointer(report_data, "{}", {ppp}"{}"{pps}, {}{});\n'.format(funcPrintName, valuePrintName, prefix, value.name, **postProcSpec))
        return checkExpr
    #
    # Process struct member validation code, performing name suibstitution if required
    def processStructMemberCode(self, line, funcName, memberNamePrefix, memberDisplayNamePrefix, postProcSpec):
        # Build format specifier list
        kwargs = {}
        if '{postProcPrefix}' in line:
            # If we have a tuple that includes a format string and format parameters, need to use ParameterName class
            if type(memberDisplayNamePrefix) is tuple:
                kwargs['postProcPrefix'] = 'ParameterName('
            else:
                kwargs['postProcPrefix'] = postProcSpec['ppp']
        if '{postProcSuffix}' in line:
            # If we have a tuple that includes a format string and format parameters, need to use ParameterName class
            if type(memberDisplayNamePrefix) is tuple:
                kwargs['postProcSuffix'] = ', ParameterName::IndexVector{{ {}{} }})'.format(postProcSpec['ppi'], memberDisplayNamePrefix[1])
            else:
                kwargs['postProcSuffix'] = postProcSpec['pps']
        if '{postProcInsert}' in line:
            # If we have a tuple that includes a format string and format parameters, need to use ParameterName class
            if type(memberDisplayNamePrefix) is tuple:
                kwargs['postProcInsert'] = '{}{}, '.format(postProcSpec['ppi'], memberDisplayNamePrefix[1])
            else:
                kwargs['postProcInsert'] = postProcSpec['ppi']
        if '{funcName}' in line:
            kwargs['funcName'] = funcName
        if '{valuePrefix}' in line:
            kwargs['valuePrefix'] = memberNamePrefix
        if '{displayNamePrefix}' in line:
            # Check for a tuple that includes a format string and format parameters to be used with the ParameterName class
            if type(memberDisplayNamePrefix) is tuple:
                kwargs['displayNamePrefix'] = memberDisplayNamePrefix[0]
            else:
                kwargs['displayNamePrefix'] = memberDisplayNamePrefix

        if kwargs:
            # Need to escape the C++ curly braces
            if 'IndexVector' in line:
                line = line.replace('IndexVector{ ', 'IndexVector{{ ')
                line = line.replace(' }),', ' }}),')
            return line.format(**kwargs)
        return line
    #
    # Process struct validation code for inclusion in function or parent struct validation code
    def expandStructCode(self, lines, funcName, memberNamePrefix, memberDisplayNamePrefix, indent, output, postProcSpec):
        for line in lines:
            if output:
                output[-1] += '\n'
            if type(line) is list:
                for sub in line:
                    output.append(self.processStructMemberCode(indent + sub, funcName, memberNamePrefix, memberDisplayNamePrefix, postProcSpec))
            else:
                output.append(self.processStructMemberCode(indent + line, funcName, memberNamePrefix, memberDisplayNamePrefix, postProcSpec))
        return output
    #
    # Process struct pointer/array validation code, perfoeming name substitution if required
    def expandStructPointerCode(self, prefix, value, lenValue, funcName, valueDisplayName, postProcSpec):
        expr = []
        expr.append('if ({}{} != NULL)\n'.format(prefix, value.name))
        expr.append('{')
        indent = self.incIndent(None)
        if lenValue:
            # Need to process all elements in the array
            indexName = lenValue.name.replace('Count', 'Index')
            expr[-1] += '\n'
            if lenValue.ispointer:
                # If the length value is a pointer, de-reference it for the count.
                expr.append(indent + 'for (uint32_t {iname} = 0; {iname} < *{}{}; ++{iname})\n'.format(prefix, lenValue.name, iname=indexName))
            else:
                expr.append(indent + 'for (uint32_t {iname} = 0; {iname} < {}{}; ++{iname})\n'.format(prefix, lenValue.name, iname=indexName))
            expr.append(indent + '{')
            indent = self.incIndent(indent)
            # Prefix for value name to display in error message
            if value.ispointer == 2:
                memberNamePrefix = '{}{}[{}]->'.format(prefix, value.name, indexName)
                memberDisplayNamePrefix = ('{}[%i]->'.format(valueDisplayName), indexName)
            else:
                memberNamePrefix = '{}{}[{}].'.format(prefix, value.name, indexName)
                memberDisplayNamePrefix = ('{}[%i].'.format(valueDisplayName), indexName)
        else:
            memberNamePrefix = '{}{}->'.format(prefix, value.name)
            memberDisplayNamePrefix = '{}->'.format(valueDisplayName)
        #
        # Expand the struct validation lines
        expr = self.expandStructCode(self.validatedStructs[value.type], funcName, memberNamePrefix, memberDisplayNamePrefix, indent, expr, postProcSpec)
        #
        if lenValue:
            # Close if and for scopes
            indent = self.decIndent(indent)
            expr.append(indent + '}\n')
        expr.append('}\n')
        return expr
    #
    # Generate the parameter checking code
    def genFuncBody(self, funcName, values, valuePrefix, displayNamePrefix, structTypeName):
        lines = []    # Generated lines of code
        unused = []   # Unused variable names
        for value in values:
            usedLines = []
            lenParam = None
            #
            # Prefix and suffix for post processing of parameter names for struct members.  Arrays of structures need special processing to include the array index in the full parameter name.
            postProcSpec = {}
            postProcSpec['ppp'] = '' if not structTypeName else '{postProcPrefix}'
            postProcSpec['pps'] = '' if not structTypeName else '{postProcSuffix}'
            postProcSpec['ppi'] = '' if not structTypeName else '{postProcInsert}'
            #
            # Generate the full name of the value, which will be printed in the error message, by adding the variable prefix to the value name
            valueDisplayName = '{}{}'.format(displayNamePrefix, value.name)
            #
            # Check for NULL pointers, ignore the inout count parameters that
            # will be validated with their associated array
            if (value.ispointer or value.isstaticarray) and not value.iscount:
                #
                # Parameters for function argument generation
                req = 'true'    # Paramerter cannot be NULL
                cpReq = 'true'  # Count pointer cannot be NULL
                cvReq = 'true'  # Count value cannot be 0
                lenDisplayName = None # Name of length parameter to print with validation messages; parameter name with prefix applied
                #
                # Generate required/optional parameter strings for the pointer and count values
                if value.isoptional:
                    req = 'false'
                if value.len:
                    # The parameter is an array with an explicit count parameter
                    lenParam = self.getLenParam(values, value.len)
                    lenDisplayName = '{}{}'.format(displayNamePrefix, lenParam.name)
                    if lenParam.ispointer:
                        # Count parameters that are pointers are inout
                        if type(lenParam.isoptional) is list:
                            if lenParam.isoptional[0]:
                                cpReq = 'false'
                            if lenParam.isoptional[1]:
                                cvReq = 'false'
                        else:
                            if lenParam.isoptional:
                                cpReq = 'false'
                    else:
                        if lenParam.isoptional:
                            cvReq = 'false'
                #
                # The parameter will not be processes when tagged as 'noautovalidity'
                # For the pointer to struct case, the struct pointer will not be validated, but any
                # members not tagged as 'noatuvalidity' will be validated
                if value.noautovalidity:
                    # Log a diagnostic message when validation cannot be automatically generated and must be implemented manually
                    self.logMsg('diag', 'ParameterValidation: No validation for {} {}'.format(structTypeName if structTypeName else funcName, value.name))
                else:
                    #
                    # If this is a pointer to a struct with an sType field, verify the type
                    if value.type in self.structTypes:
                        usedLines += self.makeStructTypeCheck(valuePrefix, value, lenParam, req, cvReq, cpReq, funcName, lenDisplayName, valueDisplayName, postProcSpec)
                    # If this is an input handle array that is not allowed to contain NULL handles, verify that none of the handles are VK_NULL_HANDLE
                    elif value.type in self.handleTypes and value.isconst and not self.isHandleOptional(value, lenParam):
                        usedLines += self.makeHandleCheck(valuePrefix, value, lenParam, req, cvReq, funcName, lenDisplayName, valueDisplayName, postProcSpec)
                    elif value.type in self.flags and value.isconst:
                        usedLines += self.makeFlagsArrayCheck(valuePrefix, value, lenParam, req, cvReq, funcName, lenDisplayName, valueDisplayName, postProcSpec)
                    elif value.isbool and value.isconst:
                        usedLines.append('skipCall |= validate_bool32_array(report_data, "{}", {ppp}"{}"{pps}, {ppp}"{}"{pps}, {pf}{}, {pf}{}, {}, {});\n'.format(funcName, lenDisplayName, valueDisplayName, lenParam.name, value.name, cvReq, req, pf=valuePrefix, **postProcSpec))
                    elif value.israngedenum and value.isconst:
                        enumRange = self.enumRanges[value.type]
                        usedLines.append('skipCall |= validate_ranged_enum_array(report_data, "{}", {ppp}"{}"{pps}, {ppp}"{}"{pps}, "{}", {}, {}, {pf}{}, {pf}{}, {}, {});\n'.format(funcName, lenDisplayName, valueDisplayName, value.type, enumRange[0], enumRange[1], lenParam.name, value.name, cvReq, req, pf=valuePrefix, **postProcSpec))
                    elif value.name == 'pNext':
                        # We need to ignore VkDeviceCreateInfo and VkInstanceCreateInfo, as the loader manipulates them in a way that is not documented in vk.xml
                        if not structTypeName in ['VkDeviceCreateInfo', 'VkInstanceCreateInfo']:
                            usedLines += self.makeStructNextCheck(valuePrefix, value, funcName, valueDisplayName, postProcSpec)
                    else:
                        usedLines += self.makePointerCheck(valuePrefix, value, lenParam, req, cvReq, cpReq, funcName, lenDisplayName, valueDisplayName, postProcSpec)
                    #
                    # If this is a pointer to a struct (input), see if it contains members that need to be checked
                    if value.type in self.validatedStructs and value.isconst:
                        usedLines.append(self.expandStructPointerCode(valuePrefix, value, lenParam, funcName, valueDisplayName, postProcSpec))
            # Non-pointer types
            else:
                #
                # The parameter will not be processes when tagged as 'noautovalidity'
                # For the struct case, the struct type will not be validated, but any
                # members not tagged as 'noatuvalidity' will be validated
                if value.noautovalidity:
                    # Log a diagnostic message when validation cannot be automatically generated and must be implemented manually
                    self.logMsg('diag', 'ParameterValidation: No validation for {} {}'.format(structTypeName if structTypeName else funcName, value.name))
                else:
                    if value.type in self.structTypes:
                        stype = self.structTypes[value.type]
                        usedLines.append('skipCall |= validate_struct_type(report_data, "{}", {ppp}"{}"{pps}, "{sv}", &({}{vn}), {sv}, false);\n'.format(
                            funcName, valueDisplayName, valuePrefix, vn=value.name, sv=stype.value, **postProcSpec))
                    elif value.type in self.handleTypes:
                        if not self.isHandleOptional(value, None):
                            usedLines.append('skipCall |= validate_required_handle(report_data, "{}", {ppp}"{}"{pps}, {}{});\n'.format(funcName, valueDisplayName, valuePrefix, value.name, **postProcSpec))
                    elif value.type in self.flags:
                        flagBitsName = value.type.replace('Flags', 'FlagBits')
                        if not flagBitsName in self.flagBits:
                            usedLines.append('skipCall |= validate_reserved_flags(report_data, "{}", {ppp}"{}"{pps}, {pf}{});\n'.format(funcName, valueDisplayName, value.name, pf=valuePrefix, **postProcSpec))
                        else:
                            flagsRequired = 'false' if value.isoptional else 'true'
                            allFlagsName = 'All' + flagBitsName
                            usedLines.append('skipCall |= validate_flags(report_data, "{}", {ppp}"{}"{pps}, "{}", {}, {pf}{}, {});\n'.format(funcName, valueDisplayName, flagBitsName, allFlagsName, value.name, flagsRequired, pf=valuePrefix, **postProcSpec))
                    elif value.isbool:
                        usedLines.append('skipCall |= validate_bool32(report_data, "{}", {ppp}"{}"{pps}, {}{});\n'.format(funcName, valueDisplayName, valuePrefix, value.name, **postProcSpec))
                    elif value.israngedenum:
                        enumRange = self.enumRanges[value.type]
                        if value.type == "VkObjectEntryTypeNVX":
                            garbage = 2
                        usedLines.append('skipCall |= validate_ranged_enum(report_data, "{}", {ppp}"{}"{pps}, "{}", {}, {}, {}{});\n'.format(funcName, valueDisplayName, value.type, enumRange[0], enumRange[1], valuePrefix, value.name, **postProcSpec))
                    #
                    # If this is a struct, see if it contains members that need to be checked
                    if value.type in self.validatedStructs:
                        memberNamePrefix = '{}{}.'.format(valuePrefix, value.name)
                        memberDisplayNamePrefix = '{}.'.format(valueDisplayName)
                        usedLines.append(self.expandStructCode(self.validatedStructs[value.type], funcName, memberNamePrefix, memberDisplayNamePrefix, '', [], postProcSpec))
            #
            # Append the parameter check to the function body for the current command
            if usedLines:
                # Apply special conditional checks
                if value.condition:
                    usedLines = self.genConditionalCall(valuePrefix, value.condition, usedLines)
                lines += usedLines
            elif not value.iscount:
                # If no expression was generated for this value, it is unreferenced by the validation function, unless
                # it is an array count, which is indirectly referenced for array valiadation.
                unused.append(value.name)
        return lines, unused
    #
    # Generate the struct member check code from the captured data
    def processStructMemberData(self):
        indent = self.incIndent(None)
        for struct in self.structMembers:
            #
            # The string returned by genFuncBody will be nested in an if check for a NULL pointer, so needs its indent incremented
            lines, unused = self.genFuncBody('{funcName}', struct.members, '{valuePrefix}', '{displayNamePrefix}', struct.name)
            if lines:
                self.validatedStructs[struct.name] = lines
    #
    # Generate the command param check code from the captured data
    def processCmdData(self):
        indent = self.incIndent(None)
        for command in self.commands:
            # Skip first parameter if it is a dispatch handle (everything except vkCreateInstance)
            startIndex = 0 if command.name == 'vkCreateInstance' else 1
            lines, unused = self.genFuncBody(command.name, command.params[startIndex:], '', '', None)
            if lines:
                cmdDef = self.getCmdDef(command) + '\n'
                cmdDef += '{\n'
                # Process unused parameters, Ignoring the first dispatch handle parameter, which is not
                # processed by parameter_validation (except for vkCreateInstance, which does not have a
                # handle as its first parameter)
                if unused:
                    for name in unused:
                        cmdDef += indent + 'UNUSED_PARAMETER({});\n'.format(name)
                    if len(unused) > 0:
                        cmdDef += '\n'
                cmdDef += indent + 'bool skipCall = false;\n'
                for line in lines:
                    cmdDef += '\n'
                    if type(line) is list:
                        for sub in line:
                            cmdDef += indent + sub
                    else:
                        cmdDef += indent + line
                cmdDef += '\n'
                cmdDef += indent + 'return skipCall;\n'
                cmdDef += '}\n'
                self.appendSection('command', cmdDef)