[llvm] r360902 - Resubmit: [Salvage] Change salvage debug info implementation to use DW_OP_LLVM_convert where needed
Stephen Tozer via llvm-commits
llvm-commits at lists.llvm.org
Thu May 16 07:41:01 PDT 2019
Author: stozer
Date: Thu May 16 07:41:01 2019
New Revision: 360902
URL: http://llvm.org/viewvc/llvm-project?rev=360902&view=rev
Log:
Resubmit: [Salvage] Change salvage debug info implementation to use DW_OP_LLVM_convert where needed
Fixes issue: https://bugs.llvm.org/show_bug.cgi?id=40645
Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop casts
impossible. With the recent addition of DW_OP_LLVM_convert this salvaging is
now possible, and so can be used to fix the attached bug as well as any cases
where SExt instruction results are lost in the debugging metadata. This patch
introduces this fix by expanding the salvage debug info method to cover these
cases using the new operator.
Differential revision: https://reviews.llvm.org/D61184
Added:
llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll (with props)
Modified:
llvm/trunk/lib/Transforms/Utils/Local.cpp
llvm/trunk/test/Transforms/EarlyCSE/debug-info-undef.ll
llvm/trunk/test/Transforms/InstCombine/cast-mul-select.ll
llvm/trunk/test/Transforms/InstCombine/unavailable-debug.ll
Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=360902&r1=360901&r2=360902&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/Local.cpp Thu May 16 07:41:01 2019
@@ -1690,8 +1690,27 @@ DIExpression *llvm::salvageDebugInfoImpl
// No-op casts and zexts are irrelevant for debug info.
if (CI->isNoopCast(DL) || isa<ZExtInst>(&I))
return SrcDIExpr;
- return nullptr;
- } else if (auto *GEP = dyn_cast<GetElementPtrInst>(&I)) {
+
+ Type *Type = CI->getType();
+ // Casts other than Trunc or SExt to scalar types cannot be salvaged.
+ if (Type->isVectorTy() || (!isa<TruncInst>(&I) && !isa<SExtInst>(&I)))
+ return nullptr;
+
+ Value *FromValue = CI->getOperand(0);
+ unsigned FromTypeBitSize = FromValue->getType()->getScalarSizeInBits();
+
+ unsigned ToTypeBitSize = Type->getScalarSizeInBits();
+
+ // The result of the cast will be sign extended iff the instruction is a
+ // SExt; signedness is otherwise irrelevant on the expression stack.
+ unsigned Encoding =
+ isa<SExtInst>(&I) ? dwarf::DW_ATE_signed : dwarf::DW_ATE_unsigned;
+
+ return applyOps({dwarf::DW_OP_LLVM_convert, FromTypeBitSize, Encoding,
+ dwarf::DW_OP_LLVM_convert, ToTypeBitSize, Encoding});
+ }
+
+ if (auto *GEP = dyn_cast<GetElementPtrInst>(&I)) {
unsigned BitWidth =
M.getDataLayout().getIndexSizeInBits(GEP->getPointerAddressSpace());
// Rewrite a constant GEP into a DIExpression.
Added: llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll?rev=360902&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll (added)
+++ llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll Thu May 16 07:41:01 2019
@@ -0,0 +1,25 @@
+; RUN: opt %s -debugify -early-cse -S | FileCheck %s
+define i32 @foo(i64 %nose, i32 %more) {
+; CHECK-LABEL: @foo(
+; CHECK: call void @llvm.dbg.value(metadata i64 %nose, metadata [[V1:![0-9]+]], metadata !DIExpression(DW_OP_LLVM_convert, 64, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned
+; CHECK: call void @llvm.dbg.value(metadata i64 %nose.shift, metadata [[V2:![0-9]+]]
+; CHECK: call void @llvm.dbg.value(metadata i64 %nose.shift, metadata [[V3:![0-9]+]], metadata !DIExpression(DW_OP_LLVM_convert, 64, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned
+
+entry:
+ %nose.trunc = trunc i64 %nose to i32
+ %nose.shift = lshr i64 %nose, 32
+ %nose.trunc.2 = trunc i64 %nose.shift to i32
+ %add = add nsw i32 %more, 1
+ ret i32 %add
+}
+
+!llvm.module.flags = !{!0, !1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 1, !"wchar_size", i32 2}
+!1 = !{i32 7, !"PIC Level", i32 2}
+!2 = !{!"clang version 9.0.0 "}
+
+; CHECK: [[V1]] = !DILocalVariable(
+; CHECK: [[V2]] = !DILocalVariable(
+; CHECK: [[V3]] = !DILocalVariable(
Propchange: llvm/trunk/test/DebugInfo/salvage-cast-debug-info.ll
------------------------------------------------------------------------------
svn:executable = *
Modified: llvm/trunk/test/Transforms/EarlyCSE/debug-info-undef.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/EarlyCSE/debug-info-undef.ll?rev=360902&r1=360901&r2=360902&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/EarlyCSE/debug-info-undef.ll (original)
+++ llvm/trunk/test/Transforms/EarlyCSE/debug-info-undef.ll Thu May 16 07:41:01 2019
@@ -10,7 +10,7 @@ entry:
%0 = load i8, i8* @a, align 1, !dbg !19, !tbaa !20
%conv = sext i8 %0 to i16, !dbg !19
-; CHECK: call void @llvm.dbg.value(metadata i16 undef, metadata !17, metadata !DIExpression()), !dbg !18
+; CHECK: call void @llvm.dbg.value(metadata i8 %0, metadata !17, metadata !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 16, DW_ATE_signed, DW_OP_stack_value)), !dbg !18
; CHECK-NEXT: call i32 (...) @optimize_me_not()
call void @llvm.dbg.value(metadata i16 %conv, metadata !17, metadata !DIExpression()), !dbg !18
Modified: llvm/trunk/test/Transforms/InstCombine/cast-mul-select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cast-mul-select.ll?rev=360902&r1=360901&r2=360902&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/cast-mul-select.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/cast-mul-select.ll Thu May 16 07:41:01 2019
@@ -13,6 +13,8 @@ define i32 @mul(i32 %x, i32 %y) {
; we preserve the debug information in the resulting
; instruction.
; DBGINFO-LABEL: @mul(
+; DBGINFO-NEXT: call void @llvm.dbg.value(metadata i32 %x
+; DBGINFO-NEXT: call void @llvm.dbg.value(metadata i32 %y
; DBGINFO-NEXT: [[C:%.*]] = mul i32 {{.*}}
; DBGINFO-NEXT: [[D:%.*]] = and i32 {{.*}}
; DBGINFO-NEXT: call void @llvm.dbg.value(metadata i32 [[C]]
Modified: llvm/trunk/test/Transforms/InstCombine/unavailable-debug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/unavailable-debug.ll?rev=360902&r1=360901&r2=360902&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/unavailable-debug.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/unavailable-debug.ll Thu May 16 07:41:01 2019
@@ -2,7 +2,7 @@
; Make sure to update the debug value after dead code elimination.
; CHECK: %call = call signext i8 @b(i32 6), !dbg !39
-; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 undef, metadata !30, metadata !DIExpression()), !dbg !38
+; CHECK-NEXT: call void @llvm.dbg.value(metadata i8 %call, metadata !30, metadata !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)), !dbg !38
@e = common local_unnamed_addr global i8 0, align 1, !dbg !0
@c = common local_unnamed_addr global i32 0, align 4, !dbg !6
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