[DebugInfo] LiveDebugValues: move DBG_VALUE creation into VarLoc class

Rather than having a mixture of location-state shared between DBG_VALUEs
and VarLoc objects in LiveDebugValues, this patch makes VarLoc the
master record of variable locations. The refactoring means that the
transfer of locations from one place to another is always a performed by
an operation on an existing VarLoc, that produces another transferred
VarLoc. DBG_VALUEs are only created at the end of LiveDebugValues, once
all locations are known. As a plus, there is now only one method where
DBG_VALUEs can be created.

The test case added covers a circumstance that is now impossible to
express in LiveDebugValues: if an already-indirect DBG_VALUE is spilt,
previously it would have been restored-from-spill as a direct DBG_VALUE.
We now don't lose this information along the way, as VarLocs always
refer back to the "original" non-transfer DBG_VALUE, and we can always
work out whether a location was "originally" indirect.

Differential Revision: https://reviews.llvm.org/D67398

llvm-svn: 373727

1 files changed, 140 insertions, 1 deletions

diff --git a/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir b/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir
index aedb31371bd..ded90d4a681 100644
--- a/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir
+++ b/llvm/test/DebugInfo/MIR/X86/live-debug-values-restore.mir
@@ -7,6 +7,7 @@
 #   'g': test for a crash from PR42773
 #   'h': complex expressions should be restored
 #   'i': spills should be restored across block boundaries
+#   'j': indirect DBG_VALUEs should be indirect after restoration
 
 # #define FORCE_SPILL() \
 #   __asm volatile("" : : : \
@@ -24,6 +25,7 @@
 # CHECK: ![[QVAR:[0-9]+]] = !DILocalVariable(name: "q",
 # CHECK: ![[RVAR:[0-9]+]] = !DILocalVariable(name: "r",
 # CHECK: ![[SVAR:[0-9]+]] = !DILocalVariable(name: "s",
+# CHECK: ![[TVAR:[0-9]+]] = !DILocalVariable(name: "t",
 
 # Ascertain that the spill has been recognized and manifested in a DBG_VALUE.
 # CHECK: MOV64mr $rsp,{{.*-8.*}}killed{{.*}}$rdi :: (store 8 into %stack.0)
@@ -81,7 +83,7 @@
     %0 = load i32, i32* %add.ptr, align 4, !dbg !223, !tbaa !24
     ret i32 %0, !dbg !228
   }
- 
+
   define dso_local i32 @i(i32* readonly %p) local_unnamed_addr !dbg !307 {
   entry:
     br label %foo
@@ -101,6 +103,25 @@
     ret i32 %0, !dbg !328
   }
 
+  define dso_local i32 @j(i32* readonly %p) local_unnamed_addr !dbg !402 {
+  entry:
+    br label %foo
+
+  foo:
+    call void @llvm.dbg.value(metadata i32* %p, metadata !404, metadata !DIExpression()), !dbg !405
+    %tobool = icmp eq i32* %p, null, !dbg !406
+    br i1 %tobool, label %if.end, label %if.then, !dbg !408
+  
+  if.then:                                          ; preds = %entry
+    tail call void asm sideeffect "", "~{rax},~{rbx},~{rcx},~{rdx},~{rsi},~{rdi},~{rbp},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{dirflag},~{fpsr},~{flags}"(), !dbg !409, !srcloc !411
+    br label %if.end, !dbg !412
+  
+  if.end:                                           ; preds = %entry, %if.then
+    %add.ptr = getelementptr inbounds i32, i32* %p, i64 1, !dbg !413
+    %0 = load i32, i32* %add.ptr, align 4, !dbg !414, !tbaa !24
+    ret i32 %0, !dbg !415
+  }
+
   declare void @llvm.dbg.value(metadata, metadata, metadata)
   
   !llvm.dbg.cu = !{!0}
@@ -181,6 +202,21 @@
   !322 = !DILocation(line: 109, column: 14, scope: !307)
   !323 = !DILocation(line: 109, column: 10, scope: !307)
   !328 = !DILocation(line: 109, column: 3, scope: !307)
+  !401 = !DIBasicType(name: "looong int", size: 64, encoding: DW_ATE_signed)
+  !402 = distinct !DISubprogram(name: "j", scope: !0, file: !1, line: 105, type: !8, scopeLine: 105, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !403)
+  !403 = !{!404}
+  !404 = !DILocalVariable(name: "t", arg: 1, scope: !402, file: !1, line: 105, type: !401)
+  !405 = !DILocation(line: 105, column: 12, scope: !402)
+  !406 = !DILocation(line: 106, column: 7, scope: !407)
+  !407 = distinct !DILexicalBlock(scope: !402, file: !1, line: 106, column: 7)
+  !408 = !DILocation(line: 106, column: 7, scope: !402)
+  !409 = !DILocation(line: 107, column: 5, scope: !410)
+  !410 = distinct !DILexicalBlock(scope: !407, file: !1, line: 106, column: 10)
+  !411 = !{i32 -2147471544}
+  !412 = !DILocation(line: 108, column: 3, scope: !410)
+  !413 = !DILocation(line: 109, column: 14, scope: !402)
+  !414 = !DILocation(line: 109, column: 10, scope: !402)
+  !415 = !DILocation(line: 109, column: 3, scope: !402)
 ...
 ---
 name:            f
@@ -595,3 +631,106 @@ body:             |
     RETQ $eax, debug-location !328
 
 ...
+---
+# Test that if an unspilt DBG_VALUE starts as an indirect DBG_VALUE, then it
+# is restored as an indirect DBG_VALUE. FIXME: Note that for the intervening
+# period of being a spilt location there is still a missing layer of
+# indirection.
+
+# CHECK-LABEL: name: j
+# CHECK-LABEL: bb.0.entry:
+# CHECK:       DBG_VALUE $rdi, 0, ![[TVAR]], !DIExpression()
+# CHECK-LABEL: bb.1.if.then:
+# CHECK:       DBG_VALUE $rsp, 0, ![[TVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus)
+# CHECK:       INLINEASM
+# CHECK:       DBG_VALUE ${{[a-zA-Z0-9]+}}, 0, ![[TVAR]], !DIExpression()
+# CHECK-LABEL: bb.2.if.end
+
+name:            j
+tracksRegLiveness: true
+liveins:         
+  - { reg: '$rdi', virtual-reg: '' }
+frameInfo:       
+  stackSize:       48
+  offsetAdjustment: -48
+  maxAlignment:    8
+  cvBytesOfCalleeSavedRegisters: 48
+fixedStack:      
+  - { id: 0, type: spill-slot, offset: -56, size: 8, alignment: 8, stack-id: default,
+      callee-saved-register: '$rbx', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, type: spill-slot, offset: -48, size: 8, alignment: 16, stack-id: default,
+      callee-saved-register: '$r12', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 2, type: spill-slot, offset: -40, size: 8, alignment: 8, stack-id: default,
+      callee-saved-register: '$r13', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 3, type: spill-slot, offset: -32, size: 8, alignment: 16, stack-id: default,
+      callee-saved-register: '$r14', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 4, type: spill-slot, offset: -24, size: 8, alignment: 8, stack-id: default,
+      callee-saved-register: '$r15', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 5, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: default,
+      callee-saved-register: '$rbp', callee-saved-restored: true, debug-info-variable: '', 
+      debug-info-expression: '', debug-info-location: '' }
+stack:           
+  - { id: 0, name: '', type: spill-slot, offset: -64, size: 8, alignment: 8, 
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+constants:       []
+body:             |
+  bb.0.entry:
+    successors: %bb.2, %bb.1
+    liveins: $rdi, $rbx, $r12, $r13, $r14, $r15, $rbp
+  
+    DBG_VALUE $rdi, 0, !404, !DIExpression(), debug-location !405
+    DBG_VALUE $rdi, 0, !404, !DIExpression(), debug-location !405
+    TEST64rr renamable $rdi, renamable $rdi, implicit-def $eflags, debug-location !406
+    JCC_1 %bb.2, 4, implicit $eflags, debug-location !408
+  
+  bb.1.if.then:
+    successors: %bb.2
+    liveins: $rdi, $rbp, $r15, $r14, $r13, $r12, $rbx
+  
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $r15, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    frame-setup PUSH64r killed $r13, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 40
+    frame-setup PUSH64r killed $r12, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 48
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 56
+    CFI_INSTRUCTION offset $rbx, -56
+    CFI_INSTRUCTION offset $r12, -48
+    CFI_INSTRUCTION offset $r13, -40
+    CFI_INSTRUCTION offset $r14, -32
+    CFI_INSTRUCTION offset $r15, -24
+    CFI_INSTRUCTION offset $rbp, -16
+    MOV64mr $rsp, 1, $noreg, -8, $noreg, killed renamable $rdi :: (store 8 into %stack.0)
+    INLINEASM &"", 1, 12, implicit-def dead early-clobber $rax, 12, implicit-def dead early-clobber $rbx, 12, implicit-def dead early-clobber $rcx, 12, implicit-def dead early-clobber $rdx, 12, implicit-def dead early-clobber $rsi, 12, implicit-def dead early-clobber $rdi, 12, implicit-def dead early-clobber $rbp, 12, implicit-def dead early-clobber $r8, 12, implicit-def dead early-clobber $r9, 12, implicit-def dead early-clobber $r10, 12, implicit-def dead early-clobber $r11, 12, implicit-def dead early-clobber $r12, 12, implicit-def dead early-clobber $r13, 12, implicit-def dead early-clobber $r14, 12, implicit-def dead early-clobber $r15, 12, implicit-def dead early-clobber $eflags, !20, debug-location !409
+    renamable $rdi = MOV64rm $rsp, 1, $noreg, -8, $noreg :: (load 8 from %stack.0)
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 48
+    $r12 = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 40
+    $r13 = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    $r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    $r15 = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 8
+  
+  bb.2.if.end:
+    liveins: $rdi, $rbx, $r12, $r13, $r14, $r15, $rbp
+  
+    renamable $eax = MOV32rm killed renamable $rdi, 1, $noreg, 4, $noreg, debug-location !414 :: (load 4 from %ir.add.ptr, !tbaa !24)
+    RETQ $eax, debug-location !415
+
+...