Fix Line debug info contradicting control flow semantics

This fixes 'OpLine's being inserted between branch merge instructions and branch instructions. Although this has no functional effect, SPIR-V specification clearly states that Line instructions must precede branch merge instructions Signed-off-by: Artem Gindinson <artem.gindinson@intel.com>
KhronosGroup · Sep 10, 2019 · 03389df · 03389df
1 parent 4b5307f
commit 03389df
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Showing 3 changed files with 23 additions and 11 deletions.
diff --git a/lib/SPIRV/LLVMToSPIRVDbgTran.cpp b/lib/SPIRV/LLVMToSPIRVDbgTran.cpp
@@ -205,10 +205,15 @@ void LLVMToSPIRVDbgTran::transLocationInfo() {
  LineNo = DL.getLine();
  Col = DL.getCol();
  V = SPIRVWriter->getTranslatedValue(&I);
- // TODO: Resolve issue with OpLine being inserted between
- // branch merge instruction and branch instruction.
  // According to the spec, OpLine for an OpBranch/OpBranchConditional
  // must precede the merge instruction and not the branch instruction
+ auto *VPrev = static_cast<SPIRVInstruction *>(V)->getPrevious();
+ if (VPrev->getOpCode() == OpLoopMerge ||
+ VPrev->getOpCode() == OpLoopControlINTEL) {
+ assert(V->getOpCode() == OpBranch ||
+ V->getOpCode() == OpBranchConditional);
+ V = VPrev;
+ }
  BM->addLine(V, File ? File->getId() : getDebugInfoNone()->getId(),
  LineNo, Col);
  }

diff --git a/test/DebugInfo/DebugControlFlow.cl b/test/DebugInfo/DebugControlFlow.cl
@@ -24,13 +24,19 @@ void sample() {
  } while (j++ < 10);
 }
 
+// Check that all Line items are retained
+// CHECK-SPIRV: Line [[File:[0-9]+]] 18 0
+// Control flow
 // CHECK-SPIRV: {{[0-9]+}} LoopMerge [[MergeBlock:[0-9]+]] [[ContinueTarget:[0-9]+]] 1
-// CHECK-SPIRV-NOT: ExtInst
-// TODO: Check-not for Line (can only precede LoopMerge)
-// CHECK-SPIRV: BranchConditional
+// CHECK-SPIRV-NEXT: BranchConditional
+
+// Check that all Line items are retained
+// CHECK-SPIRV: Line [[File]] 23 0
+// CHECK-SPIRV: Line [[File]] 24 0
+// Control flow
 // CHECK-SPIRV: {{[0-9]+}} LoopMerge [[MergeBlock:[0-9]+]] [[ContinueTarget:[0-9]+]] 1
-// CHECK-SPIRV-NOT: ExtInst
-// CHECK-SPIRV: Branch
+// CHECK-SPIRV-NEXT: Branch
+
 // CHECK-LLVM: br i1 %{{.*}}, label %{{.*}}, label %{{.*}}, !dbg !{{[0-9]+}}, !llvm.loop ![[MD:[0-9]+]]
 // CHECK-LLVM: ![[MD]] = distinct !{![[MD]], ![[MD_unroll:[0-9]+]]}
 // CHECK-LLVM: ![[MD_unroll]] = !{!"llvm.loop.unroll.enable"}
diff --git a/test/DebugInfo/DebugUnstructuredControlFlow.cl b/test/DebugInfo/DebugUnstructuredControlFlow.cl
@@ -15,11 +15,12 @@ void sample() {
  for(;;);
 }
 
+// Check that all Line items are retained
+// CHECK-SPIRV: Line [[File:[0-9]+]] 15 0
+// Loop control
 // CHECK-SPIRV: 2 LoopControlINTEL 1
-// CHECK-SPIRV-NOT: ExtInst
-// TODO: Check-not for Line (can only precede LoopControl)
-// CHECK-SPIRV: {{[0-9]+}} Line {{[0-9]+}} {{[0-9]+}} {{[0-9]+}}
-// CHECK-SPIRV: Branch
+// CHECK-SPIRV-NEXT: Branch
+
 // CHECK-LLVM: br label %{{.*}}, !dbg !{{[0-9]+}}, !llvm.loop ![[MD:[0-9]+]]
 // CHECK-LLVM: ![[MD]] = distinct !{![[MD]], ![[MD_unroll:[0-9]+]]}
 // CHECK-LLVM: ![[MD_unroll]] = !{!"llvm.loop.unroll.enable"}