[llvm] r290955 - [framelowering] Skip dbg values when getting next/previous instruction.

Florian Hahn via llvm-commits llvm-commits at lists.llvm.org
Wed Jan 4 04:08:35 PST 2017


Author: fhahn
Date: Wed Jan  4 06:08:35 2017
New Revision: 290955

URL: http://llvm.org/viewvc/llvm-project?rev=290955&view=rev
Log:
[framelowering] Skip dbg values when getting next/previous instruction.

Summary:
In mergeSPUpdates, debug values need to be ignored when getting the
previous element, otherwise debug data could have an impact on codegen.

In eliminateCallFramePseudoInstr, debug values after the erased element
could have an impact on codegen and should be skipped.

Closes PR31319 (https://llvm.org/bugs/show_bug.cgi?id=31319)

Reviewers: aprantl, MatzeB, mkuper

Subscribers: gbedwell, llvm-commits

Differential Revision: https://reviews.llvm.org/D27688

Added:
    llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll
    llvm/trunk/test/DebugInfo/X86/dbg-value-frame-index.ll
Modified:
    llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
    llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll

Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=290955&r1=290954&r2=290955&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Wed Jan  4 06:08:35 2017
@@ -373,6 +373,10 @@ int X86FrameLowering::mergeSPUpdates(Mac
   MachineBasicBlock::iterator PI = doMergeWithPrevious ? std::prev(MBBI) : MBBI;
   MachineBasicBlock::iterator NI = doMergeWithPrevious ? nullptr
                                                        : std::next(MBBI);
+  PI = skipDebugInstructionsBackward(PI, MBB.begin());
+  if (NI != nullptr)
+    NI = skipDebugInstructionsForward(NI, MBB.end());
+
   unsigned Opc = PI->getOpcode();
   int Offset = 0;
 
@@ -2586,6 +2590,7 @@ eliminateCallFramePseudoInstr(MachineFun
   uint64_t Amount = !reserveCallFrame ? I->getOperand(0).getImm() : 0;
   uint64_t InternalAmt = (isDestroy || Amount) ? I->getOperand(1).getImm() : 0;
   I = MBB.erase(I);
+  auto InsertPos = skipDebugInstructionsForward(I, MBB.end());
 
   if (!reserveCallFrame) {
     // If the stack pointer can be changed after prologue, turn the
@@ -2615,7 +2620,7 @@ eliminateCallFramePseudoInstr(MachineFun
 
     if (HasDwarfEHHandlers && !isDestroy &&
         MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences())
-      BuildCFI(MBB, I, DL,
+      BuildCFI(MBB, InsertPos, DL,
                MCCFIInstruction::createGnuArgsSize(nullptr, Amount));
 
     if (Amount == 0)
@@ -2629,7 +2634,7 @@ eliminateCallFramePseudoInstr(MachineFun
     // If this is a callee-pop calling convention, emit a CFA adjust for
     // the amount the callee popped.
     if (isDestroy && InternalAmt && DwarfCFI && !hasFP(MF))
-      BuildCFI(MBB, I, DL, 
+      BuildCFI(MBB, InsertPos, DL,
                MCCFIInstruction::createAdjustCfaOffset(nullptr, -InternalAmt));
 
     // Add Amount to SP to destroy a frame, or subtract to setup.
@@ -2640,13 +2645,13 @@ eliminateCallFramePseudoInstr(MachineFun
       // Merge with any previous or following adjustment instruction. Note: the
       // instructions merged with here do not have CFI, so their stack
       // adjustments do not feed into CfaAdjustment.
-      StackAdjustment += mergeSPUpdates(MBB, I, true);
-      StackAdjustment += mergeSPUpdates(MBB, I, false);
+      StackAdjustment += mergeSPUpdates(MBB, InsertPos, true);
+      StackAdjustment += mergeSPUpdates(MBB, InsertPos, false);
 
       if (StackAdjustment) {
         if (!(Fn->optForMinSize() &&
-              adjustStackWithPops(MBB, I, DL, StackAdjustment)))
-          BuildStackAdjustment(MBB, I, DL, StackAdjustment,
+              adjustStackWithPops(MBB, InsertPos, DL, StackAdjustment)))
+          BuildStackAdjustment(MBB, InsertPos, DL, StackAdjustment,
                                /*InEpilogue=*/false);
       }
     }
@@ -2662,8 +2667,9 @@ eliminateCallFramePseudoInstr(MachineFun
       // TODO: When not using precise CFA, we also need to adjust for the
       // InternalAmt here.
       if (CfaAdjustment) {
-        BuildCFI(MBB, I, DL, MCCFIInstruction::createAdjustCfaOffset(
-                                 nullptr, CfaAdjustment));
+        BuildCFI(MBB, InsertPos, DL,
+                 MCCFIInstruction::createAdjustCfaOffset(nullptr,
+                                                         CfaAdjustment));
       }
     }
 

Added: llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll?rev=290955&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll (added)
+++ llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll Wed Jan  4 06:08:35 2017
@@ -0,0 +1,72 @@
+; Test ensuring debug intrinsics do not affect generated function prologue.
+;
+; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
+
+ at a = local_unnamed_addr global i64 0, align 8
+
+define void @noDebug() {
+entry:
+  %0 = load i64, i64* @a, align 8
+  %1 = load i64, i64* @a, align 8
+  %2 = load i64, i64* @a, align 8
+  %3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
+  %4 = extractvalue { i64, i1 } %3, 0
+  %5 = tail call i64 @fn1(i64 %4, i64 %2)
+  tail call void (...) @printf()
+  tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
+  ret void
+}
+
+; CHECK-LABEL: noDebug
+; CHECK:       addq  $24, %rsp
+; CHECK:       popq  %rbx
+; CHECK-NEXT:  popq  %r14
+; CHECK-NEXT:  retq
+
+
+define void @withDebug() !dbg !18 {
+entry:
+  %0 = load i64, i64* @a, align 8
+  %1 = load i64, i64* @a, align 8
+  %2 = load i64, i64* @a, align 8
+  %3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
+  %4 = extractvalue { i64, i1 } %3, 0
+  %5 = tail call i64 @fn1(i64 %4, i64 %2)
+  tail call void @llvm.dbg.value(metadata i64 %4, i64 0, metadata !23, metadata !33), !dbg !34
+  tail call void @llvm.dbg.value(metadata i64 %5, i64 0, metadata !22, metadata !33), !dbg !35
+  tail call void (...) @printf()
+  tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
+  ret void
+}
+
+; CHECK-LABEL: withDebug
+; CHECK:       #DEBUG_VALUE: test:j <- %RBX
+; CHECK-NEXT:  addq  $24, %rsp
+; CHECK:       popq  %rbx
+; CHECK-NEXT:  popq  %r14
+; CHECK-NEXT:  retq
+
+declare { i64, i1 } @llvm.uadd.with.overflow.i64(i64, i64)
+declare i64 @fn1(i64, i64)
+
+declare void @printf(...)
+
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!15, !16}
+
+!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 4.0.0")
+!2 = !DIFile(filename: "test.cpp", directory: "")
+!11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
+!15 = !{i32 2, !"Dwarf Version", i32 4}
+!16 = !{i32 2, !"Debug Info Version", i32 3}
+!18 = distinct !DISubprogram(name: "test", scope: !2, file: !2, line: 5, unit: !1)
+!22 = !DILocalVariable(name: "i", scope: !18, file: !2, line: 6, type: !11)
+!23 = !DILocalVariable(name: "j", scope: !18, file: !2, line: 7, type: !11)
+!33 = !DIExpression()
+!34 = !DILocation(line: 7, column: 17, scope: !18)
+!35 = !DILocation(line: 6, column: 8, scope: !18)
+!36 = !DILocation(line: 9, column: 3, scope: !18)
+!37 = !DILocation(line: 10, column: 10, scope: !18)

Modified: llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll?rev=290955&r1=290954&r2=290955&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll (original)
+++ llvm/trunk/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll Wed Jan  4 06:08:35 2017
@@ -2,31 +2,56 @@
 ;
 ; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
 
-
-define i64 @noDebug(i64 %a) {
+define i64 @fn1NoDebug(i64 %a) {
   %call = call i64 @fn(i64 %a, i64 0)
   ret i64 %call
 }
 
-; CHECK-LABEL: noDebug
+; CHECK-LABEL: fn1NoDebug
 ; CHECK: popq %rcx
-; CHECK: ret
-
+; CHECK-NEXT: ret
 
-define i64 @withDebug(i64 %a) !dbg !4 {
+define i64 @fn1WithDebug(i64 %a) !dbg !4 {
   %call = call i64 @fn(i64 %a, i64 0)
   tail call void @llvm.dbg.value(metadata i64 %call, i64 0, metadata !5, metadata !6), !dbg !7
   ret i64 %call
 }
 
-; CHECK-LABEL: withDebug
+; CHECK-LABEL: fn1WithDebug
 ; CHECK: popq %rcx
-; CHECK: ret
+; CHECK-NEXT: ret
+
+%struct.Buffer = type { i8, [63 x i8] }
+
+define void @fn2NoDebug(%struct.Buffer* byval align 64 %p1) {
+  ret void
+}
+
+; CHECK-LABEL: fn2NoDebug
+; CHECK: and
+; CHECK-NOT: add
+; CHECK-NOT: sub
+; CHECK: mov
+; CHECK-NEXT: pop
+; CHECK-NEXT: ret
+
+define void @fn2WithDebug(%struct.Buffer* byval align 64 %p1) !dbg !4 {
+  call void @llvm.dbg.declare(metadata %struct.Buffer* %p1, metadata !5, metadata !6), !dbg !7
+  ret void
+}
 
+; CHECK-LABEL: fn2WithDebug
+; CHECK: and
+; CHECK-NOT: add
+; CHECK-NOT: sub
+; CHECK: mov
+; CHECK-NEXT: pop
+; CHECK-NEXT: ret
 
 declare i64 @fn(i64, i64)
 
 declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!2,!3}

Added: llvm/trunk/test/DebugInfo/X86/dbg-value-frame-index.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-value-frame-index.ll?rev=290955&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/dbg-value-frame-index.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/dbg-value-frame-index.ll Wed Jan  4 06:08:35 2017
@@ -0,0 +1,39 @@
+; RUN: llc -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
+
+define i1 @test() !dbg !4 {
+entry:
+  %end = alloca i64, align 8
+  br label %while.cond
+
+while.cond:
+  call void @llvm.dbg.value(metadata i64* %end, i64 0, metadata !5, metadata !6), !dbg !7
+  %call = call i1 @fn(i64* %end, i64* %end, i64* null, i8* null, i64 0, i64* null, i32* null, i8* null), !dbg !7
+  br label %while.body
+
+while.body:
+  br i1 0, label %while.end, label %while.cond
+
+while.end:
+  ret i1 true
+}
+
+; CHECK-LABEL: test
+; CHECK:       #DEBUG_VALUE: test:w <- [%RSP+8]
+
+declare i1 @fn(i64*, i64*, i64*, i8*, i64, i64*, i32*, i8*)
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2,!3}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 4.0.0", emissionKind: FullDebug)
+!1 = !DIFile(filename: "test.c", directory: "/")
+!2 = !{i32 2, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = distinct !DISubprogram(name: "test", type: !10, unit: !0)
+!5 = !DILocalVariable(name: "w", scope: !4, type: !9)
+!6 = !DIExpression(DW_OP_deref)
+!7 = !DILocation(line: 210, column: 12, scope: !4)
+!8 = !{!9}
+!9 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)
+!10 = !DISubroutineType(types: !8)




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