[llvm] r340267 - Change how finalizeBundle selects debug location for the BUNDLE instruction

[Bjorn Pettersson via llvm-commits]

Author: bjope
Date: Tue Aug 21 03:59:50 2018
New Revision: 340267

URL: http://llvm.org/viewvc/llvm-project?rev=340267&view=rev
Log:
Change how finalizeBundle selects debug location for the BUNDLE instruction

Summary:
Previously a BUNDLE instruction inherited the DebugLoc from the
first instruction in the bundle, even if that DebugLoc had no
DILocation. With this commit this is changed into selecting the
first DebugLoc that has a DILocation, by searching among the
bundled instructions.

The idea is to reduce amount of bundles that are lacking
debug locations.

Reviewers: #debug-info, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: JDevlieghere, mattd, llvm-commits

Differential Revision: https://reviews.llvm.org/D50639

Added:
    llvm/trunk/test/CodeGen/Hexagon/packetize-debug-loc.mir
Modified:
    llvm/trunk/lib/CodeGen/MachineInstrBundle.cpp

Modified: llvm/trunk/lib/CodeGen/MachineInstrBundle.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineInstrBundle.cpp?rev=340267&r1=340266&r2=340267&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineInstrBundle.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineInstrBundle.cpp Tue Aug 21 03:59:50 2018
@@ -105,6 +105,16 @@ bool FinalizeMachineBundles::runOnMachin
   return llvm::finalizeBundles(MF);
 }
 
+/// Return the first found DebugLoc that has a DILocation, given a range of
+/// instructions. The search range is from FirstMI to LastMI (exclusive). If no
+/// DILocation is found, then an empty location is returned.
+static DebugLoc getDebugLoc(MachineBasicBlock::instr_iterator FirstMI,
+                            MachineBasicBlock::instr_iterator LastMI) {
+  for (auto MII = FirstMI; MII != LastMI; ++MII)
+    if (MII->getDebugLoc().get())
+      return MII->getDebugLoc();
+  return DebugLoc();
+}
 
 /// finalizeBundle - Finalize a machine instruction bundle which includes
 /// a sequence of instructions starting from FirstMI to LastMI (exclusive).
@@ -123,7 +133,7 @@ void llvm::finalizeBundle(MachineBasicBl
   const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
 
   MachineInstrBuilder MIB =
-      BuildMI(MF, FirstMI->getDebugLoc(), TII->get(TargetOpcode::BUNDLE));
+      BuildMI(MF, getDebugLoc(FirstMI, LastMI), TII->get(TargetOpcode::BUNDLE));
   Bundle.prepend(MIB);
 
   SmallVector<unsigned, 32> LocalDefs;

Added: llvm/trunk/test/CodeGen/Hexagon/packetize-debug-loc.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Hexagon/packetize-debug-loc.mir?rev=340267&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Hexagon/packetize-debug-loc.mir (added)
+++ llvm/trunk/test/CodeGen/Hexagon/packetize-debug-loc.mir Tue Aug 21 03:59:50 2018
@@ -0,0 +1,58 @@
+# RUN: llc -march=hexagon -run-pass hexagon-packetizer %s -o - | FileCheck %s
+
+##############################################################################
+# This test case is not really hexagon specific, but we use hexagon to get
+# bundling.
+#
+# The goal is to verify that the BUNDLE instruction is getting the first
+# non-empty debug location among the bundled instructions.
+##############################################################################
+
+--- |
+  define void @test() { ret void }
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "llvm", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, retainedTypes: !3)
+  !1 = distinct !DISubprogram(name: "test", scope: !3, file: !3, line: 1, type: !2, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
+  !2 = !DISubroutineType(types: !3)
+  !3 = !{null}
+  !5 = !DILocation(line: 126, column: 9, scope: !2)
+  !6 = !DILocation(line: 321, column: 4, scope: !2)
+
+...
+---
+name: test
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $r1
+    $r2 = L2_loadri_io $r1, 0, debug-location !5
+    $r3 = L2_loadri_io $r1, 0, debug-location !6
+
+    $r4 = L2_loadri_io $r1, 0
+    $r5 = L2_loadri_io $r1, 0, debug-location !5
+
+    $r6 = L2_loadri_io $r1, 0, debug-location !6
+    $r7 = L2_loadri_io $r1, 0
+
+    $r8 = L2_loadri_io $r1, 0
+    $r9 = L2_loadri_io $r1, 0
+...
+
+# CHECK-LABEL: name: test
+
+# CHECK: BUNDLE
+# CHECK-SAME: debug-location [[DL1:[0-9x<>]+]]
+# CHECK-NEXT: L2_loadri_io $r1, 0, debug-location [[DL1]]
+# CHECK-NEXT: L2_loadri_io $r1, 0, debug-location [[DL2:[0-9x<>]+]]
+
+# CHECK: BUNDLE
+# CHECK-SAME: debug-location [[DL1]]
+# CHECK-NEXT: L2_loadri_io $r1, 0{{$}}
+# CHECK-NEXT: L2_loadri_io $r1, 0, debug-location [[DL1]]
+
+# CHECK: BUNDLE
+# CHECK-SAME: debug-location [[DL2]]
+# CHECK-NEXT: L2_loadri_io $r1, 0, debug-location [[DL2]]
+
+# No debug-location printouts expected for the last bundle
+# CHECK-NOT: debug-location