[llvm] r262247 - Fix PR26585 by improving the promotion of DBG_VALUEs to DW_AT_locations.
Adrian Prantl via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 29 11:49:47 PST 2016
Author: adrian
Date: Mon Feb 29 13:49:46 2016
New Revision: 262247
URL: http://llvm.org/viewvc/llvm-project?rev=262247&view=rev
Log:
Fix PR26585 by improving the promotion of DBG_VALUEs to DW_AT_locations.
When a variable is described by a single DBG_VALUE instruction we can
often use a more efficient inline DW_AT_location instead of using a
location list.
This commit makes the heuristic that decides when to apply this
optimization stricter by also verifying that the DBG_VALUE is live at the
entry of the function (instead of just checking that it is valid until
the end of the function).
<rdar://problem/24611008>
Added:
llvm/trunk/test/DebugInfo/X86/single-dbg_value.ll
Modified:
llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
llvm/trunk/test/DebugInfo/X86/PR26148.ll
llvm/trunk/test/DebugInfo/X86/parameters.ll
llvm/trunk/test/DebugInfo/X86/pieces-2.ll
llvm/trunk/test/DebugInfo/X86/pieces-3.ll
llvm/trunk/test/DebugInfo/X86/reference-argument.ll
llvm/trunk/test/DebugInfo/X86/subregisters.ll
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Feb 29 13:49:46 2016
@@ -935,6 +935,18 @@ DbgVariable *DwarfDebug::createConcreteV
return ConcreteVariables.back().get();
}
+// Determine whether this DBG_VALUE is valid at the beginning of the function.
+static bool validAtEntry(const MachineInstr *MInsn) {
+ auto MBB = MInsn->getParent();
+ // Is it in the entry basic block?
+ if (!MBB->pred_empty())
+ return false;
+ for (MachineBasicBlock::const_reverse_iterator I(MInsn); I != MBB->rend(); ++I)
+ if (!(I->isDebugValue() || I->getFlag(MachineInstr::FrameSetup)))
+ return false;
+ return true;
+}
+
// Find variables for each lexical scope.
void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU,
const DISubprogram *SP,
@@ -967,8 +979,11 @@ void DwarfDebug::collectVariableInfo(Dwa
const MachineInstr *MInsn = Ranges.front().first;
assert(MInsn->isDebugValue() && "History must begin with debug value");
- // Check if the first DBG_VALUE is valid for the rest of the function.
- if (Ranges.size() == 1 && Ranges.front().second == nullptr) {
+ // Check if there is a single DBG_VALUE, valid throughout the function.
+ // A single constant is also considered valid for the entire function.
+ if (Ranges.size() == 1 &&
+ (MInsn->getOperand(0).isImm() ||
+ (validAtEntry(MInsn) && Ranges.front().second == nullptr))) {
RegVar->initializeDbgValue(MInsn);
continue;
}
Modified: llvm/trunk/test/DebugInfo/X86/PR26148.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/PR26148.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/PR26148.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/PR26148.ll Mon Feb 29 13:49:46 2016
@@ -19,7 +19,7 @@
; AS in 26163, we expect two ranges (as opposed to one), the first one being zero sized
;
;
-; CHECK: 0x00000000: Beginning address offset: 0x0000000000000004
+; CHECK: 0x00000025: Beginning address offset: 0x0000000000000004
; CHECK: Ending address offset: 0x0000000000000004
; CHECK: Location description: 10 03 55 93 04
; CHECK: Beginning address offset: 0x0000000000000004
Modified: llvm/trunk/test/DebugInfo/X86/parameters.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/parameters.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/parameters.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/parameters.ll Mon Feb 29 13:49:46 2016
@@ -25,15 +25,19 @@
; CHECK: debug_info contents
; 0x74 is DW_OP_breg4, showing that the parameter is accessed indirectly
; (with a zero offset) from the register parameter
-; CHECK: DW_AT_location{{.*}}(<0x0{{.}}> 74 00
+; CHECK: DW_AT_location [DW_FORM_data4] ([[F_LOC:0x[0-9]*]])
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name{{.*}} = "f"
-
+;
; CHECK: DW_AT_location{{.*}}([[G_LOC:0x[0-9]*]])
; CHECK-NOT: DW_TAG
; CHECK: DW_AT_name{{.*}} = "g"
+;
; CHECK: debug_loc contents
-; CHECK-NEXT: [[G_LOC]]: Beginning
+; CHECK: [[F_LOC]]: Beginning
+; CHECK-NEXT: Ending
+; CHECK-NEXT: Location description: 74 00
+; CHECK: [[G_LOC]]: Beginning
; CHECK-NEXT: Ending
; CHECK-NEXT: Location description: 74 00
Modified: llvm/trunk/test/DebugInfo/X86/pieces-2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/pieces-2.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/pieces-2.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/pieces-2.ll Mon Feb 29 13:49:46 2016
@@ -17,10 +17,15 @@
;
;
; CHECK: DW_TAG_variable [4]
-; rax, piece 0x00000004
-; CHECK-NEXT: DW_AT_location [DW_FORM_block1]{{.*}}50 93 04
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4] ([[LOC:.*]])
; CHECK-NEXT: DW_AT_name {{.*}}"i1"
;
+; CHECK: .debug_loc
+; CHECK: [[LOC]]: Beginning address offset: 0x0000000000000004
+; CHECK-NEXT: Ending address offset: 0x0000000000000005
+; rax, piece 0x00000004
+; CHECK-NEXT: Location description: 50 93 04
+;
; ModuleID = '/Volumes/Data/llvm/test/DebugInfo/X86/sroasplit-1.ll'
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"
Modified: llvm/trunk/test/DebugInfo/X86/pieces-3.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/pieces-3.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/pieces-3.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/pieces-3.ll Mon Feb 29 13:49:46 2016
@@ -16,19 +16,22 @@
; }
;
; CHECK: DW_TAG_formal_parameter [3]
-; CHECK-NEXT: DW_AT_location [DW_FORM_data4] ([[LOC:.*]])
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4] ([[LOC1:.*]])
; CHECK-NEXT: DW_AT_name {{.*}}"outer"
; CHECK: DW_TAG_variable
-; rsi, piece 0x00000004
-; CHECK-NEXT: DW_AT_location [DW_FORM_block1] {{.*}} 54 93 04
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4] ([[LOC2:.*]])
; CHECK-NEXT: "i1"
;
; CHECK: .debug_loc
-; CHECK: [[LOC]]:
-; CHECK: Beginning address offset: 0x0000000000000000
-; CHECK: Ending address offset: 0x0000000000000008
-; rdi, piece 0x00000008, piece 0x00000004, rsi, piece 0x00000004
-; CHECK: Location description: 55 93 08 93 04 54 93 04
+; CHECK: [[LOC1]]: Beginning address offset: 0x0000000000000000
+; CHECK: Ending address offset: 0x0000000000000008
+; rdi, piece 0x00000008, piece 0x00000004, rsi, piece 0x00000004
+; CHECK-NEXT: Location description: 55 93 08 93 04 54 93 04
+; CHECK: [[LOC2]]: Beginning address offset: 0x0000000000000004
+; CHECK-NEXT: Ending address offset: 0x0000000000000008
+; rsi, piece 0x00000004
+; CHECK-NEXT: Location description: 54 93 04
+
;
; ModuleID = '/Volumes/Data/llvm/test/DebugInfo/X86/sroasplit-2.ll'
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
Modified: llvm/trunk/test/DebugInfo/X86/reference-argument.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/reference-argument.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/reference-argument.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/reference-argument.ll Mon Feb 29 13:49:46 2016
@@ -1,8 +1,9 @@
-; RUN: llc -mtriple=x86_64-apple-macosx10.9.0 -filetype=obj -O0 < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+; RUN: llc -mtriple=x86_64-apple-macosx10.9.0 -filetype=obj -O0 < %s | llvm-dwarfdump -debug-dump=all - | FileCheck %s
; ModuleID = 'aggregate-indirect-arg.cpp'
; extracted from debuginfo-tests/aggregate-indirect-arg.cpp
; v should be a pointer.
+; CHECK: .debug_info contents:
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_specification {{.*}} "_ZN1A3fooE4SVal"
; CHECK-NOT: DW_TAG_subprogram
@@ -10,9 +11,11 @@
; CHECK: DW_AT_name {{.*}} "this"
; CHECK-NOT: DW_TAG_subprogram
; CHECK: DW_TAG_formal_parameter
-; rsi+0
-; CHECK-NEXT: DW_AT_location [DW_FORM_block1] (<0x02> 74 00{{ *}})
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4] (0x00000000)
; CHECK-NEXT: DW_AT_name {{.*}} "v"
+; CHECK: .debug_loc contents:
+; rsi+0
+; CHECK: Location description: 74 00
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.9.0"
Added: llvm/trunk/test/DebugInfo/X86/single-dbg_value.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/single-dbg_value.ll?rev=262247&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/single-dbg_value.ll (added)
+++ llvm/trunk/test/DebugInfo/X86/single-dbg_value.ll Mon Feb 29 13:49:46 2016
@@ -0,0 +1,71 @@
+; RUN: %llc_dwarf -stop-after=livedebugvalues -o /dev/null %s 2>&1 \
+; RUN: | FileCheck %s --check-prefix=SANITY
+; RUN: %llc_dwarf -march=x86-64 -o - %s -filetype=obj \
+; RUN: | llvm-dwarfdump -debug-dump=all - | FileCheck %s
+;
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_variable
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4]
+; CHECK-NEXT: DW_AT_name{{.*}}"a"
+; CHECK: .debug_loc contents:
+; rax, piece 0x00000004
+; CHECK: Location description: 50 93 04
+; SANITY: DBG_VALUE
+; SANITY-NOT: DBG_VALUE
+; ModuleID = 'test.ll'
+; Compiled with -O:
+; void h(int);
+; int g();
+; void f() {
+; h(0);
+; int a = g();
+; h(a);
+; }
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+; Function Attrs: nounwind ssp uwtable
+define void @f() #0 !dbg !4 {
+entry:
+ tail call void @h(i32 0) #2, !dbg !14
+ %call = tail call i32 (...) @g() #2, !dbg !15
+ tail call void @llvm.dbg.value(metadata i32 %call, i64 0, metadata !8, metadata !16), !dbg !17
+ tail call void @h(i32 %call) #2, !dbg !18
+ ret void, !dbg !19
+}
+
+declare void @h(i32)
+
+declare i32 @g(...)
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
+
+attributes #0 = { nounwind ssp uwtable "no-frame-pointer-elim"="true" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!10, !11, !12}
+!llvm.ident = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "test.c", directory: "/Volumes/Data/llvm")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, variables: !7)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{!8}
+!8 = !DILocalVariable(name: "a", scope: !4, file: !1, line: 5, type: !9)
+!9 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!10 = !{i32 2, !"Dwarf Version", i32 2}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"PIC Level", i32 2}
+!13 = !{!"clang version 3.9.0 "}
+!14 = !DILocation(line: 4, column: 3, scope: !4)
+!15 = !DILocation(line: 5, column: 11, scope: !4)
+!16 = !DIExpression()
+!17 = !DILocation(line: 5, column: 7, scope: !4)
+!18 = !DILocation(line: 6, column: 3, scope: !4)
+!19 = !DILocation(line: 7, column: 1, scope: !4)
Modified: llvm/trunk/test/DebugInfo/X86/subregisters.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/subregisters.ll?rev=262247&r1=262246&r2=262247&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/subregisters.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/subregisters.ll Mon Feb 29 13:49:46 2016
@@ -6,8 +6,13 @@
;
; rdar://problem/16015314
;
-; CHECK: DW_AT_location [DW_FORM_block1] (<0x03> 54 93 04 )
-; CHECK: DW_AT_name [DW_FORM_strp]{{.*}} "a"
+; CHECK: .debug_info contents:
+; CHECK: DW_TAG_variable
+; CHECK-NEXT: DW_AT_location [DW_FORM_data4] (0x00000000)
+; CHECK-NEXT: DW_AT_name [DW_FORM_strp]{{.*}} "a"
+; CHECK: .debug_loc contents:
+; rsi, piece 0x00000004
+; CHECK: Location description: 54 93 04
;
; struct bar {
; int a;
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