glslang -> SPV: improved support for do-while/continue. Contributed by David Neto (dneto@google.com).

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@31205 e7fa87d3-cd2b-0410-9028-fcbf551c1848

SPIRV/GlslangToSpv.cpp

@@ -1159,19 +1159,21 @@ bool TGlslangToSpvTraverser::visitLoop(glslang::TVisit /* visit */, glslang::TIn
 
     bool bodyOut = false;
     if (! node->testFirst()) {
+        builder.endLoopHeaderWithoutTest();
         if (node->getBody()) {
             breakForLoop.push(true);
             node->getBody()->traverse(this);
             breakForLoop.pop();
         }
         bodyOut = true;
+        builder.createBranchToLoopTest();
     }
 
     if (node->getTest()) {
         node->getTest()->traverse(this);
         // the AST only contained the test computation, not the branch, we have to add it
         spv::Id condition = builder.accessChainLoad(TranslatePrecisionDecoration(node->getTest()->getType()));
-        builder.createLoopHeaderBranch(condition);
+        builder.createLoopTestBranch(condition);
     }
 
     if (! bodyOut && node->getBody()) {
@@ -1208,7 +1210,7 @@ bool TGlslangToSpvTraverser::visitBranch(glslang::TVisit /* visit */, glslang::T
     case glslang::EOpContinue:
         if (loopTerminal.top())
             loopTerminal.top()->traverse(this);
-        builder.createLoopBackEdge();
+        builder.createLoopContinue();
         break;
     case glslang::EOpReturn:
         if (inMain)

SPIRV/SpvBuilder.cpp

@@ -1719,6 +1719,7 @@ void Builder::makeNewLoop()
     loop.function = &getBuildPoint()->getParent();
     loop.header = new Block(getUniqueId(), *loop.function);
     loop.merge  = new Block(getUniqueId(), *loop.function);
+    loop.test   = NULL;
 
     loops.push(loop);
 
@@ -1730,25 +1731,55 @@ void Builder::makeNewLoop()
     setBuildPoint(loop.header);
 }
 
-void Builder::createLoopHeaderBranch(Id condition)
+void Builder::createLoopTestBranch(Id condition)
 {
-    Loop loop = loops.top();
+    Loop& loop = loops.top();
 
-    Block* body = new Block(getUniqueId(), *loop.function);
+    // If loop.test exists, then we've already generated the LoopMerge
+    // for this loop.
+    if (!loop.test)
       createMerge(OpLoopMerge, loop.merge, LoopControlMaskNone);
+
+    // Branching to the "body" block will keep control inside
+    // the loop.
+    Block* body = new Block(getUniqueId(), *loop.function);
     createConditionalBranch(condition, body, loop.merge);
     loop.function->addBlock(body);
     setBuildPoint(body);
 }
 
-// Add a back-edge (e.g "continue") for the innermost loop that you're in
+void Builder::endLoopHeaderWithoutTest()
-void Builder::createLoopBackEdge(bool implicit)
 {
-    Loop loop = loops.top();
+    Loop& loop = loops.top();
 
-    // Just branch back, and set up a block for dead code if it's a user continue
+    createMerge(OpLoopMerge, loop.merge, LoopControlMaskNone);
+    Block* body = new Block(getUniqueId(), *loop.function);
+    createBranch(body);
+    loop.function->addBlock(body);
+    setBuildPoint(body);
+
+    assert(!loop.test);
+    loop.test = new Block(getUniqueId(), *loop.function);
+}
+
+void Builder::createBranchToLoopTest()
+{
+    Loop& loop = loops.top();
+    Block* testBlock = loop.test;
+    assert(testBlock);
+    createBranch(testBlock);
+    loop.function->addBlock(testBlock);
+    setBuildPoint(testBlock);
+}
+
+void Builder::createLoopContinue()
+{
+    Loop& loop = loops.top();
+    if (loop.test)
+      createBranch(loop.test);
+    else
       createBranch(loop.header);
-    if (! implicit)
+    // Set up a block for dead code.
     createAndSetNoPredecessorBlock("post-loop-continue");
 }
 
@@ -1756,17 +1787,19 @@ void Builder::createLoopBackEdge(bool implicit)
 void Builder::createLoopExit()
 {
     createBranch(loops.top().merge);
+    // Set up a block for dead code.
     createAndSetNoPredecessorBlock("post-loop-break");
 }
 
 // Close the innermost loop
 void Builder::closeLoop()
 {
+    Loop& loop = loops.top();
+
     // Branch back to the top
-    createLoopBackEdge(true);
+    createBranch(loop.header);
 
     // Add the merge block and set the build point to it
-    Loop loop = loops.top();
     loop.function->addBlock(loop.merge);
     setBuildPoint(loop.merge);
 

SPIRV/SpvBuilder.h

@@ -357,13 +357,33 @@ public:
     // Start the beginning of a new loop.
     void makeNewLoop();
 
-    // Add the branch at the end of the loop header, and leave the build position
+    // Add the branch for the loop test, based on the given condition.
-    // in the first block of the body.
+    // The true branch goes to the block that remains inside the loop, and
-    // 'condition' is true if should exit the loop
+    // the false branch goes to the loop's merge block.  The  builder insertion
-    void createLoopHeaderBranch(Id condition);
+    // point will be placed at the start of the inside-the-loop block.
+    void createLoopTestBranch(Id condition);
 
-    // Add a back-edge (e.g "continue") for the innermost loop that you're in
+    // Finish generating the loop header block in the case where the loop test
-    void createLoopBackEdge(bool implicit=false);
+    // is at the bottom of the loop.  It will include the LoopMerge instruction
+    // and a branch to the rest of the body.  The loop header block must be
+    // separate from the rest of the body to make room for the the two kinds
+    // of *Merge instructions that might have to occur just before a branch:
+    // the loop header must have a LoopMerge as its second-last instruction,
+    // and the body might begin with a conditional branch, which must have its
+    // own SelectionMerge instruction.
+    // Also create the basic block that will contain the loop test, but don't
+    // insert it into the function yet.  Any "continue" constructs in this loop
+    // will branch to the loop test block. The builder insertion point will be
+    // placed at the start of the body block.
+    void endLoopHeaderWithoutTest();
+
+    // Generate a branch to the loop test block.  This can only be called if
+    // the loop test is at the bottom of the loop. The builder insertion point
+    // is left at the start of the test block.
+    void createBranchToLoopTest();
+
+    // Add a branch to the test of the current (innermost) loop.
+    void createLoopContinue();
 
     // Add an exit (e.g. "break") for the innermost loop that you're in
     void createLoopExit();
@@ -507,8 +527,23 @@ protected:
 
     // Data that needs to be kept in order to properly handle loops.
     struct Loop {
+        // The header is the first block generated for the loop.
+        // It dominates all the blocks in the loop, i.e. it is always
+        // executed before any others.
+        // If the loop test is executed before the body (as in "while" and
+        // "for" loops), then the header begins with the test code.
+        // Otherwise, the loop is a "do-while" loop and the header contains the
+        // start of the body of the loop (if the body exists).
         Block* header;
+        // The merge block marks the end of the loop.  Control is transferred
+        // to the merge block when either the loop test fails, or when a
+        // nested "break" is encountered.
         Block* merge;
+        // If not NULL, the test block is the basic block containing the loop
+        // test and the conditional branch back to the header or the merge
+        // block.  This is created for "do-while" loops, and is the target of
+        // any "continue" constructs that might exist.
+        Block* test;
         Function* function;
     };
 

Test/baseResults/spv.do-simple.vert.out

@@ -0,0 +1,62 @@
+spv.do-simple.vert
+
+
+
+Linked vertex stage:
+
+
+
+// Module Version 99
+// Generated by (magic number): 51a00bb
+// Id's are bound by 26
+
+                              Source GLSL 300
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4
+                              Name 4  "main"
+                              Name 9  "i"
+                              Name 24  "gl_VertexID"
+                              Name 25  "gl_InstanceID"
+                              Decorate 9(i) PrecisionHigh 
+                              Decorate 24(gl_VertexID) PrecisionHigh 
+                              Decorate 24(gl_VertexID) BuiltIn VertexId
+                              Decorate 24(gl_VertexID) NoStaticUse 
+                              Decorate 25(gl_InstanceID) PrecisionHigh 
+                              Decorate 25(gl_InstanceID) BuiltIn InstanceId
+                              Decorate 25(gl_InstanceID) NoStaticUse 
+               2:             TypeVoid
+               3:             TypeFunction 2 
+               7:             TypeInt 32 1
+               8:             TypePointer Function 7(int)
+              10:      7(int) Constant 0
+              16:      7(int) Constant 1
+              19:      7(int) Constant 10
+              20:             TypeBool
+              23:             TypePointer Input 7(int)
+ 24(gl_VertexID):     23(ptr) Variable Input 
+25(gl_InstanceID):     23(ptr) Variable Input 
+         4(main):           2 Function None 3
+               5:             Label
+            9(i):      8(ptr) Variable Function 
+                              Store 9(i) 10 
+                              Branch 11
+              11:             Label
+                              LoopMerge 12 None
+                              Branch 13
+              13:             Label
+              15:      7(int) Load 9(i) 
+              17:      7(int) IAdd 15 16
+                              Store 9(i) 17 
+                              Branch 14
+              14:             Label
+              18:      7(int) Load 9(i) 
+              21:    20(bool) SLessThan 18 19
+                              BranchConditional 21 22 12 
+              22:               Label
+                                Branch 11
+              12:             Label
+                              Branch 6
+               6:             Label
+                              Return
+                              FunctionEnd

Test/baseResults/spv.for-simple.vert.out

@@ -0,0 +1,63 @@
+spv.for-simple.vert
+
+
+
+Linked vertex stage:
+
+
+
+// Module Version 99
+// Generated by (magic number): 51a00bb
+// Id's are bound by 26
+
+                              Source GLSL 300
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4
+                              Name 4  "main"
+                              Name 9  "i"
+                              Name 18  "j"
+                              Name 24  "gl_VertexID"
+                              Name 25  "gl_InstanceID"
+                              Decorate 9(i) PrecisionHigh 
+                              Decorate 18(j) PrecisionHigh 
+                              Decorate 24(gl_VertexID) PrecisionHigh 
+                              Decorate 24(gl_VertexID) BuiltIn VertexId
+                              Decorate 24(gl_VertexID) NoStaticUse 
+                              Decorate 25(gl_InstanceID) PrecisionHigh 
+                              Decorate 25(gl_InstanceID) BuiltIn InstanceId
+                              Decorate 25(gl_InstanceID) NoStaticUse 
+               2:             TypeVoid
+               3:             TypeFunction 2 
+               7:             TypeInt 32 1
+               8:             TypePointer Function 7(int)
+              10:      7(int) Constant 0
+              14:      7(int) Constant 10
+              15:             TypeBool
+              19:      7(int) Constant 12
+              21:      7(int) Constant 1
+              23:             TypePointer Input 7(int)
+ 24(gl_VertexID):     23(ptr) Variable Input 
+25(gl_InstanceID):     23(ptr) Variable Input 
+         4(main):           2 Function None 3
+               5:             Label
+            9(i):      8(ptr) Variable Function 
+           18(j):      8(ptr) Variable Function 
+                              Store 9(i) 10 
+                              Branch 11
+              11:             Label
+              13:      7(int) Load 9(i) 
+              16:    15(bool) SLessThan 13 14
+                              LoopMerge 12 None
+                              BranchConditional 16 17 12 
+              17:               Label
+                                Store 18(j) 19 
+              20:      7(int)   Load 9(i) 
+              22:      7(int)   IAdd 20 21
+                                Store 9(i) 22 
+                                Branch 11
+              12:             Label
+                              Branch 6
+               6:             Label
+                              Return
+                              FunctionEnd

Test/baseResults/spv.while-continue-break.vert.out

@@ -0,0 +1,99 @@
+spv.while-continue-break.vert
+
+
+
+Linked vertex stage:
+
+
+
+// Module Version 99
+// Generated by (magic number): 51a00bb
+// Id's are bound by 43
+
+                              Source GLSL 300
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4
+                              Name 4  "main"
+                              Name 9  "i"
+                              Name 18  "A"
+                              Name 26  "B"
+                              Name 28  "C"
+                              Name 38  "D"
+                              Name 41  "gl_VertexID"
+                              Name 42  "gl_InstanceID"
+                              Decorate 9(i) PrecisionHigh 
+                              Decorate 18(A) PrecisionHigh 
+                              Decorate 26(B) PrecisionHigh 
+                              Decorate 28(C) PrecisionHigh 
+                              Decorate 38(D) PrecisionHigh 
+                              Decorate 41(gl_VertexID) PrecisionHigh 
+                              Decorate 41(gl_VertexID) BuiltIn VertexId
+                              Decorate 41(gl_VertexID) NoStaticUse 
+                              Decorate 42(gl_InstanceID) PrecisionHigh 
+                              Decorate 42(gl_InstanceID) BuiltIn InstanceId
+                              Decorate 42(gl_InstanceID) NoStaticUse 
+               2:             TypeVoid
+               3:             TypeFunction 2 
+               7:             TypeInt 32 1
+               8:             TypePointer Function 7(int)
+              10:      7(int) Constant 0
+              14:      7(int) Constant 10
+              15:             TypeBool
+              19:      7(int) Constant 1
+              21:      7(int) Constant 2
+              30:      7(int) Constant 5
+              39:      7(int) Constant 3
+              40:             TypePointer Input 7(int)
+ 41(gl_VertexID):     40(ptr) Variable Input 
+42(gl_InstanceID):     40(ptr) Variable Input 
+         4(main):           2 Function None 3
+               5:             Label
+            9(i):      8(ptr) Variable Function 
+           18(A):      8(ptr) Variable Function 
+           26(B):      8(ptr) Variable Function 
+           28(C):      8(ptr) Variable Function 
+           38(D):      8(ptr) Variable Function 
+                              Store 9(i) 10 
+                              Branch 11
+              11:             Label
+              13:      7(int) Load 9(i) 
+              16:    15(bool) SLessThan 13 14
+                              LoopMerge 12 None
+                              BranchConditional 16 17 12 
+              17:               Label
+                                Store 18(A) 19 
+              20:      7(int)   Load 9(i) 
+              22:      7(int)   SMod 20 21
+              23:    15(bool)   IEqual 22 10
+                                SelectionMerge 25 None
+                                BranchConditional 23 24 25 
+              24:                 Label
+                                  Store 26(B) 21 
+                                  Branch 11
+              27:                 Label
+                                  Store 28(C) 21 
+                                  Branch 25
+              25:               Label
+              29:      7(int)   Load 9(i) 
+              31:      7(int)   SMod 29 30
+              32:    15(bool)   IEqual 31 10
+                                SelectionMerge 34 None
+                                BranchConditional 32 33 34 
+              33:                 Label
+                                  Store 26(B) 21 
+                                  Branch 12
+              35:                 Label
+                                  Store 28(C) 21 
+                                  Branch 34
+              34:               Label
+              36:      7(int)   Load 9(i) 
+              37:      7(int)   IAdd 36 19
+                                Store 9(i) 37 
+                                Branch 11
+              12:             Label
+                              Store 38(D) 39 
+                              Branch 6
+               6:             Label
+                              Return
+                              FunctionEnd

Test/baseResults/spv.while-simple.vert.out

@@ -0,0 +1,58 @@
+spv.while-simple.vert
+
+
+
+Linked vertex stage:
+
+
+
+// Module Version 99
+// Generated by (magic number): 51a00bb
+// Id's are bound by 24
+
+                              Source GLSL 300
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Vertex 4
+                              Name 4  "main"
+                              Name 9  "i"
+                              Name 22  "gl_VertexID"
+                              Name 23  "gl_InstanceID"
+                              Decorate 9(i) PrecisionHigh 
+                              Decorate 22(gl_VertexID) PrecisionHigh 
+                              Decorate 22(gl_VertexID) BuiltIn VertexId
+                              Decorate 22(gl_VertexID) NoStaticUse 
+                              Decorate 23(gl_InstanceID) PrecisionHigh 
+                              Decorate 23(gl_InstanceID) BuiltIn InstanceId
+                              Decorate 23(gl_InstanceID) NoStaticUse 
+               2:             TypeVoid
+               3:             TypeFunction 2 
+               7:             TypeInt 32 1
+               8:             TypePointer Function 7(int)
+              10:      7(int) Constant 0
+              14:      7(int) Constant 10
+              15:             TypeBool
+              19:      7(int) Constant 1
+              21:             TypePointer Input 7(int)
+ 22(gl_VertexID):     21(ptr) Variable Input 
+23(gl_InstanceID):     21(ptr) Variable Input 
+         4(main):           2 Function None 3
+               5:             Label
+            9(i):      8(ptr) Variable Function 
+                              Store 9(i) 10 
+                              Branch 11
+              11:             Label
+              13:      7(int) Load 9(i) 
+              16:    15(bool) SLessThan 13 14
+                              LoopMerge 12 None
+                              BranchConditional 16 17 12 
+              17:               Label
+              18:      7(int)   Load 9(i) 
+              20:      7(int)   IAdd 18 19
+                                Store 9(i) 20 
+                                Branch 11
+              12:             Label
+                              Branch 6
+               6:             Label
+                              Return
+                              FunctionEnd

Test/runtests

@@ -36,6 +36,16 @@ if [ -a localtestlist ]
     done < localtestlist
 fi
 
+#
+# SPIR-V code generation tests
+#
+grep -v "^#" test-spirv-list | while read t; do
+    echo Running SPIR-V $t...
+    b=`basename $t`
+    $EXE -H $t > $TARGETDIR/$b.out
+    diff -b $BASEDIR/$b.out $TARGETDIR/$b.out
+done
+
 #
 # grouped shaders for bulk (faster) tests
 #

Test/spv.do-simple.vert

@@ -0,0 +1,7 @@
+#version 300 es
+void main() {
+  int i = 0;
+  do {
+    i++;
+  } while(i<10);
+}

Test/spv.do-while-continue-break.vert

@@ -0,0 +1,20 @@
+#version 300 es
+void main() {
+  int i = 0;
+  int A, B, C, D, E, F, G;
+  do {
+    A = 0;
+    if (i == 2) {
+      B = 1;
+      continue;
+      C = 2;
+    }
+    if (i == 5) {
+      D = 3;
+      break;
+      E = 42;
+    }
+    F = 99;
+  }  while (++i < 19);
+  G = 12;
+}

Test/spv.for-continue-break.vert

@@ -0,0 +1,20 @@
+#version 300 es
+void main() {
+  int i;
+  int A, B, C, D, E, F, G;
+  for (i=0; i < 10 ; i++) {
+    A = 1;
+    if (i%2 ==0) {
+      B = 1;
+      continue;
+      C = 1;
+    }
+    if (i%3 == 0) {
+      D = 1;
+      break;
+      E = 1;
+    }
+    F = 12;
+  }
+  G = 99;
+}

Test/spv.for-simple.vert

@@ -0,0 +1,8 @@
+#version 300 es
+void main() {
+  int i;
+  int j;
+  for (i=0; i < 10 ; i++) {
+    j = 12;
+  }
+}

Test/spv.while-continue-break.vert

@@ -0,0 +1,20 @@
+#version 300 es
+void main() {
+  int i = 0;
+  int A, B, C, D;
+  while (i<10) {
+    A = 1;
+    if (i%2 == 0) {
+      B = 2;
+      continue;
+      C = 2;
+    }
+    if (i%5 == 0) {
+      B = 2;
+      break;
+      C = 2;
+    }
+    i++;
+  }
+  D = 3;
+}

Test/spv.while-simple.vert

@@ -0,0 +1,7 @@
+#version 300 es
+void main() {
+  int i = 0;
+  while (i<10) {
+    i++;
+  }
+}

Test/test-spirv-list

@@ -0,0 +1,9 @@
+# Test looping constructs.
+# No tests yet for making sure break and continue from a nested loop
+# goes to the innermost target.
+spv.do-simple.vert
+spv.do-while-continue-break.vert
+spv.for-continue-break.vert
+spv.for-simple.vert
+spv.while-continue-break.vert
+spv.while-simple.vert