[llvm] 09b832e - Support emitting complex expressions that include entry values

[Adrian Prantl via llvm-commits]

Author: Adrian Prantl
Date: 2021-02-15T11:09:09-08:00
New Revision: 09b832e74f6c71c2023a3094727bc5c24c639985

URL: https://github.com/llvm/llvm-project/commit/09b832e74f6c71c2023a3094727bc5c24c639985
DIFF: https://github.com/llvm/llvm-project/commit/09b832e74f6c71c2023a3094727bc5c24c639985.diff

LOG: Support emitting complex expressions that include entry values

This patch enables AsmPrinter support for complex expression with
entry values. It shouldn't AsmPrinter's call whether these are safe or
not but the pass who introduces the DW_OP_LLVM_entry_value. This patch
on its own has no effect on clang.

Differential Revision: https://reviews.llvm.org/D96559

Added: 
    llvm/test/DebugInfo/MIR/X86/complex-entryvalue.mir

Modified: 
    llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index aee0f4cedc00..3e664b375c39 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -285,20 +285,21 @@ bool DwarfExpression::addMachineRegExpression(const TargetRegisterInfo &TRI,
   // a call site parameter expression and if that expression is just a register
   // location, emit it with addBReg and offset 0, because we should emit a DWARF
   // expression representing a value, rather than a location.
-  if (!isMemoryLocation() && !HasComplexExpression &&
-      (!isParameterValue() || isEntryValue())) {
+  if ((!isParameterValue() && !isMemoryLocation() && !HasComplexExpression) ||
+      isEntryValue()) {
     for (auto &Reg : DwarfRegs) {
       if (Reg.DwarfRegNo >= 0)
         addReg(Reg.DwarfRegNo, Reg.Comment);
       addOpPiece(Reg.SubRegSize);
     }
 
-    if (isEntryValue())
+    if (isEntryValue()) {
       finalizeEntryValue();
 
-    if (isEntryValue() && !isIndirect() && !isParameterValue() &&
-        DwarfVersion >= 4)
-      emitOp(dwarf::DW_OP_stack_value);
+      if (!isIndirect() && !isParameterValue() && !HasComplexExpression &&
+          DwarfVersion >= 4)
+        emitOp(dwarf::DW_OP_stack_value);
+    }
 
     DwarfRegs.clear();
     return true;

diff  --git a/llvm/test/DebugInfo/MIR/X86/complex-entryvalue.mir b/llvm/test/DebugInfo/MIR/X86/complex-entryvalue.mir
new file mode 100644
index 000000000000..cc7e6dbc08e3
--- /dev/null
+++ b/llvm/test/DebugInfo/MIR/X86/complex-entryvalue.mir
@@ -0,0 +1,53 @@
+# RUN: llc -filetype=obj -start-after=livedebugvalues -verify-machineinstrs -march=x86-64 -o - %s | llvm-dwarfdump - | FileCheck %s
+# CHECK: DW_AT_location	(DW_OP_entry_value(DW_OP_reg5 RDI), DW_OP_constu 0xffffffff, DW_OP_and, DW_OP_lit0, DW_OP_plus)
+--- |
+  ; ModuleID = '/tmp/e.c'
+  source_filename = "/tmp/e.c"
+  target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-apple-macosx11.0.0"
+  
+  ; Function Attrs: norecurse nounwind readnone ssp uwtable willreturn
+  define dso_local void @f(i32 %i) local_unnamed_addr #0 !dbg !8 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %i, metadata !14, metadata !DIExpression()), !dbg !15
+    ret void, !dbg !16
+  }
+  
+  ; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+  declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+  
+  attributes #0 = { norecurse nounwind readnone ssp uwtable willreturn }
+  attributes #1 = { nofree nosync nounwind readnone speculatable willreturn }
+  
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!3, !4, !5, !6}
+  
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, emissionKind: FullDebug)
+  !1 = !DIFile(filename: "/tmp/e.c", directory: "/")
+  !2 = !{}
+  !3 = !{i32 7, !"Dwarf Version", i32 4}
+  !4 = !{i32 2, !"Debug Info Version", i32 3}
+  !5 = !{i32 1, !"wchar_size", i32 4}
+  !6 = !{i32 7, !"PIC Level", i32 2}
+  !8 = distinct !DISubprogram(name: "f", scope: !9, file: !9, line: 1, type: !10, scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !13)
+  !9 = !DIFile(filename: "/tmp/e.c", directory: "")
+  !10 = !DISubroutineType(types: !11)
+  !11 = !{null, !12}
+  !12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !13 = !{!14}
+  !14 = !DILocalVariable(name: "i", arg: 1, scope: !8, file: !9, line: 1, type: !12)
+  !15 = !DILocation(line: 0, scope: !8)
+  !16 = !DILocation(line: 1, column: 16, scope: !8)
+
+...
+---
+name:            f
+body:             |
+  bb.0.entry:
+    DBG_VALUE $edi, $noreg, !14, !DIExpression(DW_OP_LLVM_entry_value, 1, DW_OP_lit0, DW_OP_plus), debug-location !15
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    $rbp = frame-setup MOV64rr $rsp
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !16
+    RETQ debug-location !16
+
+...