mewin/glslang
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

HLSL: split textures used for both shadow and non-shadow modes

Browse Source 
A single texture can statically appear in code mixed with a shadow sampler
and a non-shadow sampler.  This would be create invalid SPIR-V, unless
one of them is provably dead.

The previous detection of this happened before DCE, so some shaders would
trigger the error even though they wouldn't after DCE.  To handle that
case, this PR splits the texture into two: one with each mode.  It sets
"needsLegalization" (if that happens for any texture) to warn that this shader
will need post-compilation legalization.

If the texture is only used with one of the two modes, behavior is as it
was before.
This commit is contained in:
LoopDawg
2017-10-05 16:25:52 -06:00
parent 263986eb6e
commit 73c57bbe50
6 changed files with 260 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

94
hlsl/hlslParseHelper.cpp
View File

@@ -2936,37 +2936,66 @@ TIntermAggregate* HlslParseContext::handleSamplerTextureCombine(const TSourceLoc
TSampler samplerType = argTex->getType().getSampler();
samplerType.combined = true;
samplerType.shadow = argSampler->getType().getSampler().shadow;
// TODO:
// This block exists until the spec no longer requires shadow modes on texture objects.
// It can be deleted after that, along with the shadowTextureVariant member.
{
// ** TODO: **
// This forces the texture's shadow state to be the sampler's
// shadow state. This can't work if a single texture is used with
// both comparison and non-comparison samplers, so an error is
// reported if the shader does that.
//
// If this code is ever removed (possibly due to a relaxation in the
// SPIR-V rules), also remove the textureShadowMode member variable.
const bool shadowMode = argSampler->getType().getSampler().shadow;
TIntermSymbol* texSymbol = argTex->getAsSymbolNode();
if (texSymbol == nullptr)
texSymbol = argTex->getAsBinaryNode()->getLeft()->getAsSymbolNode();
if (texSymbol != nullptr) {
const auto textureShadowModeEntry = textureShadowMode.find(texSymbol->getId());
// Check to see if this texture has been given a different shadow mode already.
if (textureShadowModeEntry != textureShadowMode.end() &&
textureShadowModeEntry->second != samplerType.shadow) {
error(loc, "all uses of texture must use the same shadow mode", "", "");
return nullptr;
}
argTex->getWritableType().getSampler().shadow = samplerType.shadow;
textureShadowMode[texSymbol->getId()] = samplerType.shadow;
if (texSymbol == nullptr) {
error(loc, "unable to find texture symbol", "", "");
return nullptr;
}
}
// This forces the texture's shadow state to be the sampler's
// shadow state. This depends on downstream optimization to
// DCE one variant in [shadow, nonshadow] if both are present,
// or the SPIR-V module would be invalid.
int newId = texSymbol->getId();
// Check to see if this texture has been given a shadow mode already.
// If so, look up the one we already have.
const auto textureShadowEntry = textureShadowVariant.find(texSymbol->getId());
if (textureShadowEntry != textureShadowVariant.end())
newId = textureShadowEntry->second->get(shadowMode);
else
textureShadowVariant[texSymbol->getId()] = new tShadowTextureSymbols;
// Sometimes we have to create another symbol (if this texture has been seen before,
// and we haven't created the form for this shadow mode).
if (newId == -1) {
TType texType;
texType.shallowCopy(argTex->getType());
texType.getSampler().shadow = shadowMode; // set appropriate shadow mode.
globalQualifierFix(loc, texType.getQualifier());
TVariable* newTexture = makeInternalVariable(texSymbol->getName(), texType);
trackLinkage(*newTexture);
newId = newTexture->getUniqueId();
}
assert(newId != -1);
if (textureShadowVariant.find(newId) == textureShadowVariant.end())
textureShadowVariant[newId] = textureShadowVariant[texSymbol->getId()];
textureShadowVariant[newId]->set(shadowMode, newId);
// Remember this shadow mode in the texture and the merged type.
argTex->getWritableType().getSampler().shadow = shadowMode;
samplerType.shadow = shadowMode;
texSymbol->setId(newId);
}
txcombine->setType(TType(samplerType, EvqTemporary));
txcombine->setLoc(loc);
@@ -9506,14 +9535,19 @@ void HlslParseContext::fixTextureShadowModes()
TSampler& sampler = (*symbol)->getWritableType().getSampler();
if (sampler.isTexture()) {
const auto shadowMode = textureShadowMode.find((*symbol)->getUniqueId());
if (shadowMode != textureShadowMode.end())
sampler.shadow = shadowMode->second;
const auto shadowMode = textureShadowVariant.find((*symbol)->getUniqueId());
if (shadowMode != textureShadowVariant.end()) {
if (shadowMode->second->overloaded())
// Texture needs legalization if it's been seen with both shadow and non-shadow modes.
intermediate.setNeedsLegalization();
sampler.shadow = shadowMode->second->isShadowId((*symbol)->getUniqueId());
}
}
}
}
// post-processing
void HlslParseContext::finish()
{
@@ -9523,15 +9557,15 @@ void HlslParseContext::finish()
error(mipsOperatorMipArg.back().loc, "unterminated mips operator:", "", "");
}
removeUnusedStructBufferCounters();
addPatchConstantInvocation();
fixTextureShadowModes();
// Communicate out (esp. for command line) that we formed AST that will make
// illegal AST SPIR-V and it needs transforms to legalize it.
if (intermediate.needsLegalization())
infoSink.info << "WARNING: AST will form illegal SPIR-V; need to transform to legalize";
removeUnusedStructBufferCounters();
addPatchConstantInvocation();
fixTextureShadowModes();
TParseContextBase::finish();
}

27
hlsl/hlslParseHelper.h
View File

@@ -457,10 +457,29 @@ protected:
TVector<tMipsOperatorData> mipsOperatorMipArg;
// This can be removed if and when the texture shadow workarounnd in
// HlslParseContext::handleSamplerTextureCombine is removed. It maps
// texture symbol IDs to the shadow modes of samplers they were combined with.
TMap<int, bool> textureShadowMode;
// A texture object may be used with shadow and non-shadow samplers, but both may not be
// alive post-DCE in the same shader. We do not know at compilation time which are alive: that's
// only known post-DCE. If a texture is used both ways, we create two textures, and
// leave the elimiation of one to the optimizer. This maps the shader variant to
// the shadow variant.
//
// This can be removed if and when the texture shadow code in
// HlslParseContext::handleSamplerTextureCombine is removed.
struct tShadowTextureSymbols {
tShadowTextureSymbols() { symId.fill(-1); }
void set(bool shadow, int id) { symId[int(shadow)] = id; }
int get(bool shadow) const { return symId[int(shadow)]; }
// True if this texture has been seen with both shadow and non-shadow modes
bool overloaded() const { return symId[0] != -1 && symId[1] != -1; }
bool isShadowId(int id) const { return symId[1] == id; }
private:
std::array<int, 2> symId;
};
TMap<int, tShadowTextureSymbols*> textureShadowVariant;
};
// This is the prefix we use for built-in methods to avoid namespace collisions with