commit a2858d9bdd8a69dfc4b964a18bfa8817419a78b7
author John Kessenich <cepheus@frii.com> Wed Jan 31 08:11:18 2018 -0700
committer John Kessenich <cepheus@frii.com> Thu Feb 01 00:55:08 2018 -0700
tree 5e34f80733763228414acb307936ca6660c248d5
parent e18fd20d5c5eab5f4cd80596333f3333c4409e72

GLSL: Implement GL_EXT_control_flow_attributes.

See https://github.com/KhronosGroup/GLSL/pull/11.

SPIRV/GlslangToSpv.cpp

diff --git a/SPIRV/GlslangToSpv.cpp b/SPIRV/GlslangToSpv.cpp
index b7b6597..ec7dd17 100755
--- a/SPIRV/GlslangToSpv.cpp
+++ b/SPIRV/GlslangToSpv.cpp
@@ -131,7 +131,7 @@
     spv::ImageFormat TranslateImageFormat(const glslang::TType& type);
     spv::SelectionControlMask TranslateSelectionControl(const glslang::TIntermSelection&) const;
     spv::SelectionControlMask TranslateSwitchControl(const glslang::TIntermSwitch&) const;
-    spv::LoopControlMask TranslateLoopControl(const glslang::TIntermLoop&) const;
+    spv::LoopControlMask TranslateLoopControl(const glslang::TIntermLoop&, unsigned int& dependencyLength) const;
     spv::StorageClass TranslateStorageClass(const glslang::TType&);
     spv::Id createSpvVariable(const glslang::TIntermSymbol*);
     spv::Id getSampledType(const glslang::TSampler&);
@@ -767,7 +767,9 @@
     return spv::SelectionControlMaskNone;
 }
 
-spv::LoopControlMask TGlslangToSpvTraverser::TranslateLoopControl(const glslang::TIntermLoop& loopNode) const
+// return a non-0 dependency if the dependency argument must be set
+spv::LoopControlMask TGlslangToSpvTraverser::TranslateLoopControl(const glslang::TIntermLoop& loopNode,
+    unsigned int& dependencyLength) const
 {
     spv::LoopControlMask control = spv::LoopControlMaskNone;
 
@@ -775,6 +777,12 @@
         control = control | spv::LoopControlDontUnrollMask;
     if (loopNode.getUnroll())
         control = control | spv::LoopControlUnrollMask;
+    if (loopNode.getLoopDependency() == glslang::TIntermLoop::dependencyInfinite)
+        control = control | spv::LoopControlDependencyInfiniteMask;
+    else if (loopNode.getLoopDependency() > 0) {
+        control = control | spv::LoopControlDependencyLengthMask;
+        dependencyLength = loopNode.getLoopDependency();
+    }
 
     return control;
 }
@@ -2137,9 +2145,8 @@
     builder.createBranch(&blocks.head);
 
     // Loop control:
-    const spv::LoopControlMask control = TranslateLoopControl(*node);
-
-    // TODO: dependency length
+    unsigned int dependencyLength = glslang::TIntermLoop::dependencyInfinite;
+    const spv::LoopControlMask control = TranslateLoopControl(*node, dependencyLength);
 
     // Spec requires back edges to target header blocks, and every header block
     // must dominate its merge block.  Make a header block first to ensure these
@@ -2149,7 +2156,7 @@
     // including merges of its own.
     builder.setLine(node->getLoc().line);
     builder.setBuildPoint(&blocks.head);
-    builder.createLoopMerge(&blocks.merge, &blocks.continue_target, control);
+    builder.createLoopMerge(&blocks.merge, &blocks.continue_target, control, dependencyLength);
     if (node->testFirst() && node->getTest()) {
         spv::Block& test = builder.makeNewBlock();
         builder.createBranch(&test);

SPIRV/SpvBuilder.cpp

diff --git a/SPIRV/SpvBuilder.cpp b/SPIRV/SpvBuilder.cpp
index 408634e..f877a2e 100644
--- a/SPIRV/SpvBuilder.cpp
+++ b/SPIRV/SpvBuilder.cpp
@@ -2573,12 +2573,15 @@
     buildPoint->addInstruction(std::unique_ptr<Instruction>(merge));
 }
 
-void Builder::createLoopMerge(Block* mergeBlock, Block* continueBlock, unsigned int control)
+void Builder::createLoopMerge(Block* mergeBlock, Block* continueBlock, unsigned int control,
+                              unsigned int dependencyLength)
 {
     Instruction* merge = new Instruction(OpLoopMerge);
     merge->addIdOperand(mergeBlock->getId());
     merge->addIdOperand(continueBlock->getId());
     merge->addImmediateOperand(control);
+    if ((control & LoopControlDependencyLengthMask) != 0)
+        merge->addImmediateOperand(dependencyLength);
     buildPoint->addInstruction(std::unique_ptr<Instruction>(merge));
 }
 

SPIRV/SpvBuilder.h

diff --git a/SPIRV/SpvBuilder.h b/SPIRV/SpvBuilder.h
index 1d8fd8b..9f15989 100755
--- a/SPIRV/SpvBuilder.h
+++ b/SPIRV/SpvBuilder.h
@@ -561,7 +561,7 @@
 
     void createBranch(Block* block);
     void createConditionalBranch(Id condition, Block* thenBlock, Block* elseBlock);
-    void createLoopMerge(Block* mergeBlock, Block* continueBlock, unsigned int control);
+    void createLoopMerge(Block* mergeBlock, Block* continueBlock, unsigned int control, unsigned int dependencyLength);
 
     // Sets to generate opcode for specialization constants.
     void setToSpecConstCodeGenMode() { generatingOpCodeForSpecConst = true; }

SPIRV/doc.cpp

diff --git a/SPIRV/doc.cpp b/SPIRV/doc.cpp
index 7d817b4..809af4c 100755
--- a/SPIRV/doc.cpp
+++ b/SPIRV/doc.cpp
@@ -2558,6 +2558,7 @@
     InstructionDesc[OpLoopMerge].operands.push(OperandId, "'Merge Block'");
     InstructionDesc[OpLoopMerge].operands.push(OperandId, "'Continue Target'");
     InstructionDesc[OpLoopMerge].operands.push(OperandLoop, "");
+    InstructionDesc[OpLoopMerge].operands.push(OperandOptionalLiteral, "");
 
     InstructionDesc[OpSelectionMerge].operands.push(OperandId, "'Merge Block'");
     InstructionDesc[OpSelectionMerge].operands.push(OperandSelect, "");