Files
UnrealEngine/Engine/Source/Developer/ShaderPreprocessor/Private/ShaderPreprocessor.cpp
2025-05-18 13:04:45 +08:00

848 lines
35 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#include "ShaderPreprocessor.h"
#include "Misc/FileHelper.h"
#include "Misc/Paths.h"
#include "Misc/ScopeLock.h"
#include "Modules/ModuleManager.h"
#include "PreprocessorPrivate.h"
#include "ShaderCompilerDefinitions.h"
#include "stb_preprocess/preprocessor.h"
#include "stb_preprocess/stb_alloc.h"
#include "stb_preprocess/stb_ds.h"
static TAutoConsoleVariable<int32> CVarShaderCompilerThreadLocalPreprocessBuffer(
TEXT("r.ShaderCompiler.ThreadLocalPreprocessBuffer"),
1280 * 1024,
TEXT("Amount to preallocate for preprocess output per worker thread, to save reallocation overhead in the preprocessor."),
ECVF_Default
);
namespace
{
const FString PlatformHeader = TEXT("/Engine/Public/Platform.ush");
void LogMandatoryHeaderError(const FShaderCompilerInput& Input, FShaderPreprocessOutput& Output)
{
FString Path = Input.VirtualSourceFilePath;
FString Message = FString::Printf(TEXT("Error: Shader is required to include %s"), *PlatformHeader);
Output.LogError(MoveTemp(Path), MoveTemp(Message), 1);
}
}
// Utility function to wrap FShaderPreprocessDependencies hash table lookups -- used with FComparePathInSource / FCompareResultPath below
template <typename CompareType, typename... ArgsType>
FORCEINLINE uint32 DependencyHashTableFind(const FShaderPreprocessDependencies& Dependencies, const CompareType& Compare, uint32 KeyHash, ArgsType... Args)
{
const FHashTable& HashTable = Compare.GetHashTable(Dependencies);
for (uint32 Index = HashTable.First(KeyHash); HashTable.IsValid(Index); Index = HashTable.Next(Index))
{
if (Compare.Equals(Dependencies.Dependencies[Index], Args...))
{
return Index;
}
}
return INDEX_NONE;
}
struct FComparePathInSource
{
static FORCEINLINE const FHashTable& GetHashTable(const FShaderPreprocessDependencies& Dependencies)
{
return Dependencies.BySource;
}
static FORCEINLINE bool Equals(const FShaderPreprocessDependency& Dependency, const ANSICHAR* PathInSource, uint32 PathLen, FXxHash64 PathHash, const ANSICHAR* ParentPathAnsi)
{
return Dependency.EqualsPathInSource(PathInSource, PathLen, PathHash, ParentPathAnsi);
}
};
struct FCompareResultPath
{
static FORCEINLINE const FHashTable& GetHashTable(const FShaderPreprocessDependencies& Dependencies)
{
return Dependencies.ByResult;
}
static FORCEINLINE bool Equals(const FShaderPreprocessDependency& Dependency, const FString& ResultPath, uint32 ResultPathHash)
{
return Dependency.EqualsResultPath(ResultPath, ResultPathHash);
}
};
static void AddStbDefine(stb_arena* MacroArena, macro_definition**& StbDefines, const TCHAR* Name, const TCHAR* Value);
static void AddStbDefines(stb_arena* MacroArena, macro_definition**& StbDefines, const FShaderCompilerDefinitions& Defines);
class FShaderPreprocessorUtilities
{
public:
static void PopulateDefines(const FShaderCompilerEnvironment& Environment, const FShaderCompilerDefinitions& AdditionalDefines, stb_arena* MacroArena, macro_definition**& OutDefines)
{
arrsetcap(OutDefines, Environment.Definitions->Num() + AdditionalDefines.Num());
AddStbDefines(MacroArena, OutDefines, *Environment.Definitions);
AddStbDefines(MacroArena, OutDefines, AdditionalDefines);
}
};
//////////////////////////////////////////////////////////////////////////
extern "C"
{
// adapter functions for STB memory allocation
void* StbMalloc(size_t Size)
{
void* Alloc = FMemory::Malloc(Size);
return Alloc;
}
void* StbRealloc(void* Pointer, size_t Size)
{
void* Alloc = FMemory::Realloc(Pointer, Size);
return Alloc;
}
void StbFree(void* Pointer)
{
return FMemory::Free(Pointer);
}
ANSICHAR* StbStrDup(const ANSICHAR* InString)
{
if (InString)
{
int32 Len = FCStringAnsi::Strlen(InString) + 1;
ANSICHAR* Result = reinterpret_cast<ANSICHAR*>(StbMalloc(Len));
return FCStringAnsi::Strncpy(Result, InString, Len);
}
return nullptr;
}
}
struct FStbLoadedInclude
{
const ANSICHAR* FileName = nullptr; // Points to ResultPath in FShaderPreprocessDependenciesShared, or LocalFileName
const ANSICHAR* Data = nullptr; // Points to SharedData, LocalData, or data from FShaderCompilerEnvironment
size_t DataLength = 0;
FShaderSharedAnsiStringPtr SharedData;
TArray<ANSICHAR> LocalData;
TArray<ANSICHAR> LocalFileName;
};
static bool HasDependencyFromResultPath(const FShaderPreprocessDependencies& Dependencies, const FString& ResultPath, const FStbLoadedInclude* CacheShared);
struct FStbPreprocessContext
{
const FShaderCompilerInput& ShaderInput;
const FShaderCompilerEnvironment& Environment;
TMap<FString, FStbLoadedInclude> LoadedIncludesCache;
// Shared includes from PreprocessDependencies, VertexFactoryDependencies, and Environment.IncludeVirtualPathToSharedContentsMap
// are stored in this array instead of the map, indexed sequentially. Avoids hash table overhead of "LoadedIncludesCache".
TArray<FStbLoadedInclude> LoadedIncludesCacheShared;
FShaderPreprocessDependenciesShared PreprocessDependencies;
FShaderPreprocessDependenciesShared VertexFactoryDependencies;
FHashTable SharedContentsHash; // Case insensitive hash table pointing at LoadedIncludesCacheShared with entries from IncludeVirtualPathToSharedContentsMap
uint32 SharedIncludeIndex = INDEX_NONE; // Index in LoadedIncludesCacheShared propagated from StbResolveInclude to StbLoadFile
uint32 VertexFactoryOffset = INDEX_NONE; // Vertex factory dependencies start at this offset in LoadedIncludesCacheShared
uint32 VirtualSharedContentsOffset = INDEX_NONE; // Virtual shared contents start at this offset in LoadedIncludesCacheShared
// TEXT macro processing state
struct FTextEntry
{
uint32 Index;
uint32 Hash;
uint32 Offset;
bool bIsAssert;
FString SourceText;
FString ConvertedText;
FString EncodedText;
};
TArray<FTextEntry> TextEntries;
TArray<ANSICHAR> TextMacroSubstituted;
uint32 TextGlobalCount = 0;
uint32 TextAssertCount = 0;
uint32 TextPrintfCount = 0;
bool bInAssert = false;
bool HasIncludedHeader(const FString& Header)
{
// Checks if a given header has been included. Note that the header may be encountered through one of our FShaderPreprocessDependencies structures,
// so if those are valid, we need to check the corresponding elements in the LoadedIncludesCacheShared array to see if the path was encountered.
return
(PreprocessDependencies.IsValid() && HasDependencyFromResultPath(*PreprocessDependencies, Header, &LoadedIncludesCacheShared[0])) ||
(VertexFactoryDependencies.IsValid() && HasDependencyFromResultPath(*VertexFactoryDependencies, Header, &LoadedIncludesCacheShared[VertexFactoryOffset])) ||
LoadedIncludesCache.Contains(Header);
}
bool HasIncludedMandatoryHeaders()
{
// Check if the mandatory PlatformHeader has been included ("/Engine/Public/Platform.ush")
return HasIncludedHeader(PlatformHeader);
}
void ShaderPrintGenerate(char*& PreprocessFile, TArray<FShaderDiagnosticData>* OutDiagnosticDatas);
};
static void StbLoadedIncludeTrimPaddingChecked(FStbLoadedInclude* ContentsCached)
{
// Need 15 characters beyond null terminator, so an unaligned SSE read at the null terminator can safely read 15 extra unused characters
// without going out of memory bounds. ShaderConvertAndStripComments adds this padding in the form of extra trailing zeroes. Make sure
// these zeroes are there.
static const char SixteenZeroes[16] = { 0 };
checkf(ContentsCached->DataLength >= 16 && memcmp(&ContentsCached->Data[ContentsCached->DataLength - 16], SixteenZeroes, 16) == 0,
TEXT("Shader preprocessor ANSI files must include 15 bytes of zero padding past null terminator"));
ContentsCached->DataLength -= 15;
}
static FORCEINLINE void StbLoadedIncludeTrimPadding(FStbLoadedInclude* ContentsCached)
{
// For includes cached at startup, don't bother with the assert, since we know they came from a "safe" source that always adds the padding.
ContentsCached->DataLength -= 15;
}
static const ANSICHAR* StbLoadFile(const ANSICHAR* Filename, void* RawContext, size_t* OutLength)
{
FStbPreprocessContext& Context = *reinterpret_cast<FStbPreprocessContext*>(RawContext);
// Check if we found this file in our preprocess dependencies (fast path)
if (Context.SharedIncludeIndex != INDEX_NONE)
{
FStbLoadedInclude* ContentsCached = &Context.LoadedIncludesCacheShared[Context.SharedIncludeIndex];
// Reset this after we consume it (although StbResolveInclude should clear it as well before StbLoadFile is called again)
Context.SharedIncludeIndex = INDEX_NONE;
*OutLength = ContentsCached->DataLength;
return ContentsCached->Data;
}
FString FilenameConverted = StringCast<TCHAR>(Filename).Get();
uint32 FilenameConvertedHash = GetTypeHash(FilenameConverted);
FStbLoadedInclude& ContentsCached = Context.LoadedIncludesCache.FindOrAddByHash(FilenameConvertedHash, FilenameConverted);
if (!ContentsCached.Data)
{
const FString* InMemorySource = Context.Environment.IncludeVirtualPathToContentsMap.FindByHash(FilenameConvertedHash, FilenameConverted);
if (InMemorySource)
{
check(!InMemorySource->IsEmpty());
ShaderConvertAndStripComments(*InMemorySource, ContentsCached.LocalData);
ContentsCached.Data = ContentsCached.LocalData.GetData();
ContentsCached.DataLength = ContentsCached.LocalData.Num();
}
else
{
const FThreadSafeSharedAnsiStringPtr* InMemorySourceAnsi = Context.Environment.IncludeVirtualPathToSharedContentsMap.FindByHash(FilenameConvertedHash, FilenameConverted);
if (InMemorySourceAnsi)
{
ContentsCached.Data = InMemorySourceAnsi->Get()->GetData();
ContentsCached.DataLength = InMemorySourceAnsi->Get()->Num();
}
else
{
CheckShaderHashCacheInclude(FilenameConverted, Context.ShaderInput.Target.GetPlatform(), Context.ShaderInput.ShaderFormat.ToString());
LoadShaderSourceFile(*FilenameConverted, Context.ShaderInput.Target.GetPlatform(), nullptr, nullptr, nullptr, &ContentsCached.SharedData);
ContentsCached.Data = ContentsCached.SharedData->GetData();
ContentsCached.DataLength = ContentsCached.SharedData->Num();
}
}
StbLoadedIncludeTrimPaddingChecked(&ContentsCached);
}
*OutLength = ContentsCached.DataLength;
return ContentsCached.Data;
}
static void StbFreeFile(const ANSICHAR* Filename, const ANSICHAR* Contents, void* RawContext)
{
// No-op; stripped/converted shader source will be freed from the cache in FStbPreprocessContext when it's destructed;
// we want to keep it around until that point in case includes are loaded multiple times from different source locations
}
static uint32 ResolveDependencyFromPathInSource(const FShaderPreprocessDependencies& Dependencies, const ANSICHAR* PathInSource, uint32 PathLen, FXxHash64 PathHash, const ANSICHAR* ParentPathAnsi, FStbLoadedInclude* CacheShared)
{
uint32 HashIndex = DependencyHashTableFind(Dependencies, FComparePathInSource(), GetTypeHash(PathHash), PathInSource, PathLen, PathHash, ParentPathAnsi);
if (HashIndex != INDEX_NONE)
{
// Choose the first unique instance of this result path
HashIndex = Dependencies.Dependencies[HashIndex].ResultPathUniqueIndex;
const FShaderPreprocessDependency& Dependency = Dependencies.Dependencies[HashIndex];
FStbLoadedInclude* ContentsCached = &CacheShared[HashIndex];
if (!ContentsCached->FileName)
{
ContentsCached->FileName = Dependency.ResultPath.GetData();
ContentsCached->Data = Dependency.StrippedSource->GetData();
ContentsCached->DataLength = Dependency.StrippedSource->Num();
StbLoadedIncludeTrimPadding(ContentsCached);
}
}
return HashIndex;
}
static uint32 ResolveDependencyFromResultPath(const FShaderPreprocessDependencies& Dependencies, const FString& ResultPath, uint32 ResultPathHash, FStbLoadedInclude* CacheShared)
{
// ResultPathHash is passed in twice -- once for "Find" function, and again as an argument to the "FCompareResultPath::Equals" function
uint32 HashIndex = DependencyHashTableFind(Dependencies, FCompareResultPath(), ResultPathHash, ResultPath, ResultPathHash);
if (HashIndex != INDEX_NONE)
{
const FShaderPreprocessDependency& Dependency = Dependencies.Dependencies[HashIndex];
FStbLoadedInclude* ContentsCached = &CacheShared[HashIndex];
if (!ContentsCached->FileName)
{
ContentsCached->FileName = Dependency.ResultPath.GetData();
ContentsCached->Data = Dependency.StrippedSource->GetData();
ContentsCached->DataLength = Dependency.StrippedSource->Num();
StbLoadedIncludeTrimPadding(ContentsCached);
}
}
return HashIndex;
}
// Returns true if the path in question was encountered during preprocessing, if the path is one of the paths referenced by that dependency structure.
static bool HasDependencyFromResultPath(const FShaderPreprocessDependencies& Dependencies, const FString& ResultPath, const FStbLoadedInclude* CacheShared)
{
uint32 ResultPathHash = GetTypeHash(ResultPath);
uint32 HashIndex = DependencyHashTableFind(Dependencies, FCompareResultPath(), ResultPathHash, ResultPath, ResultPathHash);
// Entry will have FileName set if it was encountered
return HashIndex != INDEX_NONE && CacheShared[HashIndex].FileName != nullptr;
}
static void CopyStringToAnsiCharArray(const TCHAR* Text, int32 TextLen, TArray<ANSICHAR>& Out)
{
Out.SetNumUninitialized(TextLen + 1);
ANSICHAR* OutData = Out.GetData();
for (int32 CharIndex = 0; CharIndex < TextLen; CharIndex++, OutData++, Text++)
{
*OutData = (ANSICHAR)*Text;
}
*OutData = 0;
}
// Adds 16 bytes of zeroes at end, to allow SSE reads at the end of the buffer without reading past the end of the heap allocation
static void CopyStringToAnsiCharArraySSEPadded(const TCHAR* Text, int32 TextLen, TArray<ANSICHAR>& Out)
{
constexpr int32 SSEPadding = 16;
Out.SetNumUninitialized(TextLen + SSEPadding);
ANSICHAR* OutData = Out.GetData();
for (int32 CharIndex = 0; CharIndex < TextLen; CharIndex++, OutData++, Text++)
{
*OutData = (ANSICHAR)*Text;
}
FMemory::Memset(OutData, 0, SSEPadding * sizeof(ANSICHAR));
}
static const ANSICHAR* StbResolveInclude(const ANSICHAR* PathInSource, uint32 PathLen, const ANSICHAR* ParentPathAnsi, void* RawContext)
{
FStbPreprocessContext& Context = *reinterpret_cast<FStbPreprocessContext*>(RawContext);
FXxHash64 PathHash = FXxHash64::HashBuffer(PathInSource, PathLen);
// Try main shader preprocess dependencies
Context.SharedIncludeIndex = INDEX_NONE;
if (Context.PreprocessDependencies.IsValid())
{
uint32 DependencyIndex = ResolveDependencyFromPathInSource(*Context.PreprocessDependencies, PathInSource, PathLen, PathHash, ParentPathAnsi, &Context.LoadedIncludesCacheShared[0]);
if (DependencyIndex != INDEX_NONE)
{
// Propagate the found index to StbLoadFile
uint32 SharedIncludeIndex = DependencyIndex;
Context.SharedIncludeIndex = SharedIncludeIndex;
return Context.LoadedIncludesCacheShared[SharedIncludeIndex].FileName;
}
}
// Try vertex factory preprocess dependencies
if (Context.VertexFactoryDependencies.IsValid())
{
uint32 DependencyIndex = ResolveDependencyFromPathInSource(*Context.VertexFactoryDependencies, PathInSource, PathLen, PathHash, ParentPathAnsi, &Context.LoadedIncludesCacheShared[Context.VertexFactoryOffset]);
if (DependencyIndex != INDEX_NONE)
{
// Propagate the found index to StbLoadFile
uint32 SharedIncludeIndex = DependencyIndex + Context.VertexFactoryOffset;
Context.SharedIncludeIndex = SharedIncludeIndex;
return Context.LoadedIncludesCacheShared[SharedIncludeIndex].FileName;
}
}
// Try SharedContentsHash
FAnsiStringView RawPathInSourceView(PathInSource, PathLen);
for (uint32 HashIndex = Context.SharedContentsHash.First(GetTypeHash(RawPathInSourceView)); Context.SharedContentsHash.IsValid(HashIndex); HashIndex = Context.SharedContentsHash.Next(HashIndex))
{
if (RawPathInSourceView == Context.LoadedIncludesCacheShared[HashIndex].FileName)
{
// Propagate the found index to StbLoadFile
Context.SharedIncludeIndex = HashIndex;
return Context.LoadedIncludesCacheShared[HashIndex].FileName;
}
}
// Slow path... Platform specific files and procedurally generated files (/Engine/Generated/Material.ush) -- typically 5% of files.
FString PathModified = FString::ConstructFromPtrSize(PathInSource, PathLen);
if (!PathModified.StartsWith(TEXT("/"))) // if path doesn't start with / it's relative, if so append the parent's folder and collapse any relative dirs
{
FString ParentFolder(ParentPathAnsi);
ParentFolder = FPaths::GetPath(ParentFolder);
PathModified = ParentFolder / PathModified;
FPaths::CollapseRelativeDirectories(PathModified);
}
FixupShaderFilePath(PathModified, Context.ShaderInput.Target.GetPlatform(), &Context.ShaderInput.ShaderPlatformName);
uint32 PathModifiedHash = GetTypeHash(PathModified);
// We need to check our preprocess dependencies again with the result path, so we get the canonical capitalization for it from the dependencies, if available.
// This case can be reached for platform includes (which aren't added to the bulk dependencies).
if (Context.PreprocessDependencies.IsValid())
{
uint32 DependencyIndex = ResolveDependencyFromResultPath(*Context.PreprocessDependencies, PathModified, PathModifiedHash, &Context.LoadedIncludesCacheShared[0]);
if (DependencyIndex != INDEX_NONE)
{
// Propagate the found index to StbLoadFile
uint32 SharedIncludeIndex = DependencyIndex;
Context.SharedIncludeIndex = SharedIncludeIndex;
return Context.LoadedIncludesCacheShared[SharedIncludeIndex].FileName;
}
}
// Try vertex factory preprocess dependencies
if (Context.VertexFactoryDependencies.IsValid())
{
uint32 DependencyIndex = ResolveDependencyFromResultPath(*Context.VertexFactoryDependencies, PathModified, PathModifiedHash, &Context.LoadedIncludesCacheShared[Context.VertexFactoryOffset]);
if (DependencyIndex != INDEX_NONE)
{
// Propagate the found index to StbLoadFile
uint32 SharedIncludeIndex = DependencyIndex + Context.VertexFactoryOffset;
Context.SharedIncludeIndex = SharedIncludeIndex;
return Context.LoadedIncludesCacheShared[SharedIncludeIndex].FileName;
}
}
// If we reach here, the include will be added to the map. Check if it's already in the map.
FStbLoadedInclude* ContentsCached = Context.LoadedIncludesCache.FindByHash(PathModifiedHash, PathModified);
if (ContentsCached)
{
// We return the same previously resolved path so preprocessor will handle #pragma once with files included with inconsistent casing correctly
return ContentsCached->FileName;
}
bool bExists =
Context.Environment.IncludeVirtualPathToContentsMap.ContainsByHash(PathModifiedHash, PathModified) ||
// LoadShaderSourceFile will load the file if it exists, but then cache it internally, so the next call in StbLoadFile will be cheap
// (and hence this is not wasteful, just performs the loading earlier)
LoadShaderSourceFile(*PathModified, Context.ShaderInput.Target.GetPlatform(), nullptr, nullptr);
if (bExists)
{
ContentsCached = &Context.LoadedIncludesCache.AddByHash(PathModifiedHash, PathModified);
// Initialize the ANSI file name in the map entry. The file itself will be loaded in StbLoadFile, but we need the ANSI string
// as the return value from this function.
CopyStringToAnsiCharArray(&PathModified[0], PathModified.Len(), ContentsCached->LocalFileName);
ContentsCached->FileName = ContentsCached->LocalFileName.GetData();
return ContentsCached->FileName;
}
return nullptr;
}
static const char* ShaderPrintTextIdentifier = "TEXT";
static const char* ShaderPrintAssertIdentifier = "UEReportAssertWithPayload";
static const char* StbCustomMacroBegin(const char* OriginalText, void* RawContext)
{
FStbPreprocessContext& Context = *reinterpret_cast<FStbPreprocessContext*>(RawContext);
// Check for assert macro
if (FCStringAnsi::Strstr(OriginalText, ShaderPrintAssertIdentifier) == OriginalText)
{
// We only need to track that we're in an assert, we don't need to do any substitution
Context.bInAssert = true;
return OriginalText;
}
// TEXT macro
check(FCStringAnsi::Strstr(OriginalText, ShaderPrintTextIdentifier) == OriginalText);
const char* TextChar = OriginalText;
while (*TextChar != '(')
{
TextChar++;
}
TextChar++;
while (*TextChar != ')' && *TextChar != '\"')
{
TextChar++;
}
// If no quoted text, that's a parse error
if (*TextChar != '\"')
{
return nullptr;
}
// We found a string, add an entry
const uint32 EntryIndex = Context.TextEntries.Num();
FStbPreprocessContext::FTextEntry& Entry = Context.TextEntries.AddDefaulted_GetRef();
Entry.Index = EntryIndex;
Entry.Offset = Context.TextGlobalCount;
Entry.bIsAssert = Context.bInAssert;
if (Entry.bIsAssert)
{
++Context.TextAssertCount;
}
else
{
++Context.TextPrintfCount;
}
// Parse the string, handling escaped characters. SourceText contains the raw text, ConvertedText removes escape back slashes,
// and EncodedText is an array of integer numeric values as ASCII.
TextChar++;
const char* TextStart = TextChar;
int32 CharCount = 0;
for (; *TextChar != '\"'; TextChar++)
{
if (*TextChar == '\\')
{
TextChar++;
}
CharCount++;
}
Entry.SourceText = FString(FAnsiStringView(TextStart, TextChar - TextStart));
Entry.ConvertedText.GetCharArray().SetNumUninitialized(CharCount + 1);
Entry.EncodedText.Reserve(CharCount * 4); // ~3 digits per character + a comma
TCHAR* ConvertedTextData = Entry.ConvertedText.GetCharArray().GetData();
int32 CharIndex = 0;
for (TextChar = TextStart; *TextChar != '\"'; TextChar++, CharIndex++)
{
if (*TextChar == '\\')
{
TextChar++;
}
ConvertedTextData[CharIndex] = *TextChar;
const char C = *TextChar;
Entry.EncodedText.AppendInt(uint8(C));
if (CharIndex + 1 != CharCount)
{
Entry.EncodedText += ',';
}
}
check(CharIndex == CharCount);
ConvertedTextData[CharIndex] = 0;
Entry.Hash = CityHash32((const char*)Entry.SourceText.GetCharArray().GetData(), sizeof(FString::ElementType) * Entry.SourceText.Len());
Context.TextGlobalCount += Entry.ConvertedText.Len();
// Generate substitution string -- need SSE padding on any text handled by the preprocessor
if (Entry.bIsAssert)
{
const FString HashString = FString::Printf(TEXT("%u"), Entry.Hash);
CopyStringToAnsiCharArraySSEPadded(*HashString, HashString.Len(), Context.TextMacroSubstituted);
}
else
{
const FString InitHashBegin(TEXT("InitShaderPrintText("));
const FString InitHashEnd(TEXT(")"));
const FString HashText = InitHashBegin + FString::FromInt(EntryIndex) + InitHashEnd;
CopyStringToAnsiCharArraySSEPadded(*HashText, HashText.Len(), Context.TextMacroSubstituted);
}
return Context.TextMacroSubstituted.GetData();
}
static void StbCustomMacroEnd(const char* OriginalText, void* RawContext, const char* SubstitutionText)
{
FStbPreprocessContext& Context = *reinterpret_cast<FStbPreprocessContext*>(RawContext);
if (FCStringAnsi::Strstr(OriginalText, ShaderPrintAssertIdentifier) == OriginalText)
{
Context.bInAssert = false;
}
}
void FStbPreprocessContext::ShaderPrintGenerate(char*& PreprocessedFile, TArray<FShaderDiagnosticData>* OutDiagnosticDatas)
{
// Check if ShaderPrintCommon.ush was included, to decide whether to add the shader print generated code
static FString ShaderPrintHeader("/Engine/Private/ShaderPrintCommon.ush");
if (!HasIncludedHeader(ShaderPrintHeader))
{
return;
}
// 1. Write a global struct containing all the entries
// 2. Write the function for fetching character for a given entry index
const uint32 EntryCount = TextEntries.Num();
FString TextChars;
if (TextPrintfCount > 0 && EntryCount > 0 && TextGlobalCount > 0)
{
// 1. Encoded character for each text entry within a single global char array
TextChars = FString::Printf(TEXT("\n\nstatic const uint TEXT_CHARS[%d] = {\n"), TextGlobalCount);
for (FTextEntry& Entry : TextEntries)
{
TextChars += FString::Printf(TEXT("\t%s%s // %d: \"%s\"\n"), *Entry.EncodedText, Entry.Index < EntryCount - 1 ? TEXT(",") : TEXT(""), Entry.Index, *Entry.SourceText);
}
TextChars += TEXT("};\n\n");
// 2. Offset within the global array
TextChars += FString::Printf(TEXT("static const uint TEXT_OFFSETS[%d] = {\n"), EntryCount + 1);
for (FTextEntry& Entry : TextEntries)
{
TextChars += FString::Printf(TEXT("\t%d, // %d: \"%s\"\n"), Entry.Offset, Entry.Index, *Entry.SourceText);
}
TextChars += FString::Printf(TEXT("\t%d // end\n"), TextGlobalCount);
TextChars += TEXT("};\n\n");
// 3. Entry hashes
TextChars += TEXT("// Hashes are computed using the CityHash32 function\n");
TextChars += FString::Printf(TEXT("static const uint TEXT_HASHES[%d] = {\n"), EntryCount);
for (FTextEntry& Entry : TextEntries)
{
TextChars += FString::Printf(TEXT("\t0x%x%s // %d: \"%s\"\n"), Entry.Hash, Entry.Index < EntryCount - 1 ? TEXT(",") : TEXT(""), Entry.Index, *Entry.SourceText);
}
TextChars += TEXT("};\n\n");
TextChars += TEXT("uint ShaderPrintGetChar(uint InIndex) { return TEXT_CHARS[InIndex]; }\n");
TextChars += TEXT("uint ShaderPrintGetOffset(FShaderPrintText InText) { return TEXT_OFFSETS[InText.Index]; }\n");
TextChars += TEXT("uint ShaderPrintGetHash(FShaderPrintText InText) { return TEXT_HASHES[InText.Index]; }\n");
}
else
{
TextChars += TEXT("uint ShaderPrintGetChar(uint Index) { return 0; }\n");
TextChars += TEXT("uint ShaderPrintGetOffset(FShaderPrintText InText) { return 0; }\n");
TextChars += TEXT("uint ShaderPrintGetHash(FShaderPrintText InText) { return 0; }\n");
}
// 3. Insert global struct data + print function
TArray<ANSICHAR> TextCharsAnsi;
CopyStringToAnsiCharArray(*TextChars, TextChars.Len(), TextCharsAnsi);
PreprocessedFile = preprocessor_file_append(PreprocessedFile, TextCharsAnsi.GetData(), TextCharsAnsi.Num() - 1);
// 4. Insert assert data into shader compilation output for runtime CPU lookup
if (OutDiagnosticDatas && TextAssertCount > 0)
{
OutDiagnosticDatas->Reserve(OutDiagnosticDatas->Num() + TextAssertCount);
for (const FTextEntry& E : TextEntries)
{
if (E.bIsAssert)
{
FShaderDiagnosticData& Data = OutDiagnosticDatas->AddDefaulted_GetRef();
Data.Hash = E.Hash;
Data.Message = E.SourceText;
}
}
}
}
class FShaderPreprocessorModule : public IModuleInterface
{
virtual void StartupModule() override
{
init_preprocessor(&StbLoadFile, &StbFreeFile, &StbResolveInclude, &StbCustomMacroBegin, &StbCustomMacroEnd);
// disable the "directive not at start of line" error; this allows a few things:
// 1. #define'ing #pragma messages - consumed by the preprocessor (to handle UESHADERMETADATA hackery)
// 2. #define'ing other #pragmas (those not processed explicitly by the preprocessor are copied into the preprocessed code
// 3. handling the HLSL infinity constant (1.#INF); STB preprocessor interprets any use of # as a directive which is not the case here
pp_set_warning_mode(PP_RESULT_directive_not_at_start_of_line, PP_RESULT_MODE_no_warning);
}
};
IMPLEMENT_MODULE(FShaderPreprocessorModule, ShaderPreprocessor);
static void AddStbDefine(stb_arena* MacroArena, macro_definition**& StbDefines, const TCHAR* Name, const TCHAR* Value)
{
TAnsiStringBuilder<256> Define;
// Define format: "%s %s" (Name Value)
Define.Append(Name);
Define.AppendChar(' ');
Define.Append(Value);
arrput(StbDefines, pp_define(MacroArena, *Define));
}
static void AddStbDefines(stb_arena* MacroArena, macro_definition**& StbDefines, const FShaderCompilerDefinitions& Defines)
{
for (FShaderCompilerDefinitions::FConstIterator It(Defines); It; ++It)
{
AddStbDefine(MacroArena, StbDefines, It.Key(), It.Value());
}
}
/**
* Preprocess a shader.
* @param OutPreprocessedShader - Upon return contains the preprocessed source code.
* @param ShaderOutput - ShaderOutput to which errors can be added.
* @param ShaderInput - The shader compiler input.
* @param AdditionalDefines - Additional defines with which to preprocess the shader.
* @param DefinesPolicy - Whether to add shader definitions as comments.
* @returns true if the shader is preprocessed without error.
*/
bool PreprocessShader(
FShaderPreprocessOutput& Output,
const FShaderCompilerInput& Input,
const FShaderCompilerEnvironment& Environment,
const FShaderCompilerDefinitions& AdditionalDefines
)
{
TRACE_CPUPROFILER_EVENT_SCOPE(PreprocessShader);
stb_arena MacroArena = { 0 };
macro_definition** StbDefines = nullptr;
FShaderPreprocessorUtilities::PopulateDefines(Environment, AdditionalDefines, &MacroArena, StbDefines);
// The substitution text generated by custom macros gets run through the preprocessor afterwards, but in some cases we want to
// run the arguments through the preprocessor before as well. The TEXT macro needs this to handle things like TEXT(__FILE__),
// where the __FILE__ macro needs to be expanded before the custom macro handler is called, so we pass "1" to enable running
// the preprocessor first. By contrast, for shader asserts, we must NOT run the preprocessor on the arguments first, because
// the assert macro sets a state flag which modifies behavior of TEXT macros inside the assert. Asserts store their TEXT tokens
// outside the shader for printing in code when an assert is triggered, while ShaderPrint stores TEXT in the shader itself.
arrput(StbDefines, pp_define_custom_macro(&MacroArena, ShaderPrintTextIdentifier, 1));
arrput(StbDefines, pp_define_custom_macro(&MacroArena, ShaderPrintAssertIdentifier, 0));
FStbPreprocessContext Context{ Input, Environment };
auto InFilename = StringCast<ANSICHAR>(*Input.VirtualSourceFilePath);
int NumDiagnostics = 0;
pp_diagnostic* Diagnostics = nullptr;
static const int32 ThreadLocalPreprocessBufferSize = CVarShaderCompilerThreadLocalPreprocessBuffer.GetValueOnAnyThread();
static thread_local char* ThreadLocalPreprocessBuffer = nullptr;
// Sanity check the buffer size so it won't OOM if a bad value is entered.
int32 ClampedPreprocessBufferSize = ThreadLocalPreprocessBufferSize ? FMath::Clamp(ThreadLocalPreprocessBufferSize, 64 * 1024, 4 * 1024 * 1024) : 0;
if (ClampedPreprocessBufferSize && !ThreadLocalPreprocessBuffer)
{
ThreadLocalPreprocessBuffer = new char[ClampedPreprocessBufferSize];
}
if (GetShaderPreprocessDependencies(*Input.VirtualSourceFilePath, Context.ShaderInput.Target.GetPlatform(), Context.PreprocessDependencies))
{
// First item in dependencies is always root file, so set that index
Context.SharedIncludeIndex = 0;
}
// Grab vertex factory dependencies if present
const FString* VertexFactoryInclude = Context.Environment.IncludeVirtualPathToContentsMap.Find(TEXT("/Engine/Generated/VertexFactory.ush"));
if (VertexFactoryInclude)
{
int32 VertexFactoryNameStart;
int32 VertexFactoryNameEnd;
if (VertexFactoryInclude->FindChar(TEXT('\"'), VertexFactoryNameStart) && VertexFactoryInclude->FindLastChar(TEXT('\"'), VertexFactoryNameEnd))
{
// Should have at least one character in our filename
check(VertexFactoryNameEnd > VertexFactoryNameStart + 1);
FString VertexFactoryFilename(FStringView(&(*VertexFactoryInclude)[VertexFactoryNameStart + 1], VertexFactoryNameEnd - (VertexFactoryNameStart + 1)));
GetShaderPreprocessDependencies(*VertexFactoryFilename, Context.ShaderInput.Target.GetPlatform(), Context.VertexFactoryDependencies);
}
}
// Initialize array of loaded includes associated with PreprocessDependencies, VertexFactoryDependencies, and Environment.IncludeVirtualPathToSharedContentsMap
Context.VertexFactoryOffset = Context.PreprocessDependencies.IsValid() ? Context.PreprocessDependencies->Dependencies.Num() : 0;
Context.VirtualSharedContentsOffset = Context.VertexFactoryOffset + (Context.VertexFactoryDependencies.IsValid() ? Context.VertexFactoryDependencies->Dependencies.Num() : 0);
Context.LoadedIncludesCacheShared.AddDefaulted(Context.VirtualSharedContentsOffset + Context.Environment.IncludeVirtualPathToSharedContentsMap.Num());
// Initialize root file dependency, if present
if (Context.PreprocessDependencies.IsValid())
{
const FShaderPreprocessDependency& Dependency = Context.PreprocessDependencies->Dependencies[0];
FStbLoadedInclude* ContentsCached = &Context.LoadedIncludesCacheShared[0];
ContentsCached->FileName = InFilename.Get();
ContentsCached->Data = Dependency.StrippedSource->GetData();
ContentsCached->DataLength = Dependency.StrippedSource->Num();
StbLoadedIncludeTrimPadding(ContentsCached);
}
// Initialize loaded includes for IncludeVirtualPathToSharedContentsMap, and generate a hash table
uint32 SharedContentsMapIndex = Context.VirtualSharedContentsOffset;
for (const auto& SharedContentsMapIt : Context.Environment.IncludeVirtualPathToSharedContentsMap)
{
FStbLoadedInclude& Include = Context.LoadedIncludesCacheShared[SharedContentsMapIndex];
// Copy name
CopyStringToAnsiCharArray(&SharedContentsMapIt.Key[0], SharedContentsMapIt.Key.Len(), Include.LocalFileName);
Include.FileName = Include.LocalFileName.GetData();
// Set data
Include.Data = SharedContentsMapIt.Value->GetData();
Include.DataLength = SharedContentsMapIt.Value->Num();
StbLoadedIncludeTrimPadding(&Include);
// Add to hash table -- GetTypeHash on string view is case insensitive
Context.SharedContentsHash.Add(GetTypeHash(FAnsiStringView(Include.LocalFileName.GetData(), Include.LocalFileName.Num() - 1)), SharedContentsMapIndex);
SharedContentsMapIndex++;
}
char* OutPreprocessedAnsi = preprocess_file(InFilename.Get(), &Context, StbDefines, arrlen(StbDefines), &Diagnostics, &NumDiagnostics, ThreadLocalPreprocessBuffer, ClampedPreprocessBufferSize);
bool HasError = false;
if (Diagnostics != nullptr)
{
for (int DiagIndex = 0; DiagIndex < NumDiagnostics; ++DiagIndex)
{
pp_diagnostic* Diagnostic = &Diagnostics[DiagIndex];
HasError |= (Diagnostic->error_level == PP_RESULT_MODE_error);
FString Message = Diagnostic->message;
if (Diagnostic->error_level == PP_RESULT_MODE_error || Diagnostic->error_level == PP_RESULT_MODE_warning)
{
FString Filename = Diagnostic->where->filename;
Output.LogError(MoveTemp(Filename), MoveTemp(Message), Diagnostic->where->line_number);
}
else
{
EMessageType Type = FilterPreprocessorError(Message);
if (Type == EMessageType::ShaderMetaData)
{
FString Directive;
ExtractDirective(Directive, Message);
Output.AddDirective(MoveTemp(Directive));
}
}
}
}
if (!HasError)
{
// Append ShaderPrint generated code at the end of the shader if necessary
Context.ShaderPrintGenerate(OutPreprocessedAnsi, &Output.EditDiagnosticDatas());
// "preprocessor_file_size" includes null terminator, so subtract one when initializing the FShaderSource (which automatically null terminates)
Output.EditSource().Set({ OutPreprocessedAnsi, preprocessor_file_size(OutPreprocessedAnsi) - 1 });
}
if (!HasError && !Context.HasIncludedMandatoryHeaders())
{
LogMandatoryHeaderError(Input, Output);
HasError = true;
}
preprocessor_file_free(OutPreprocessedAnsi, Diagnostics);
stbds_arrfree(StbDefines);
stb_arena_free(&MacroArena);
return !HasError;
}
bool PreprocessShader(
FShaderPreprocessOutput& Output,
const FShaderCompilerInput& Input,
const FShaderCompilerEnvironment& MergedEnvironment)
{
// overload instead of defaulting FShaderCompilerDefinitions arg to avoid including an internal header in a public header.
return PreprocessShader(Output, Input, MergedEnvironment, FShaderCompilerDefinitions());
}