[llvm/DebugInfo] Emit DW_OP_implicit_value when tuning for LLDB

[mib]

Summary

This patch enables emitting DWARF DW_OP_implicit_value opcode when
tuning debug information for LLDB (-debugger-tune=lldb).

This will also propagate to Darwin platforms, since they use LLDB tuning
as a default.

rdar://67406059

Signed-off-by: Med Ismail Bennani <[e-mail]>

[aprantl]

llvm/test/DebugInfo/X86/implicit_value-double.ll

15

You probably don't need to duplicate the CHECK lines — also I'm surprised this even works.

[aprantl]

Anyway, this LGTM with the tests fixed.

[mib]

Fix pre-check test failures

[JDevlieghere]

LGTM with a few nits.

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

2483–2485

llvm/test/DebugInfo/X86/implicit_value-float.ll

13

Maybe add a negative test for sce?

[mib]

It seems that the HWASAN pre-check test is also failing in D89844 (https://buildkite.com/llvm-project/premerge-checks/builds/14519) ... I also tested on Linux and the test passes so I guess this is an issue with the bot.

$ /usr/bin/python3.7 /Users/docker_user/Developer/open-source/llvm.org/build/Modular/./bin/llvm-lit -svv --filter=TestCases/sizes.cpp -- /Users/docker_user/Developer/open-source/llvm.org/build/Modular/projects/compiler-rt/test/hwasan/X86_64
Testing Time: 5.52s
  Excluded: 50
  Passed  :  1

$ uname -s 
Linux

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

2483–2485

I'm not 100% sure GDB || LLDB <-> !SCE, this is why I put it this way ... What if the -debugger-tune option is not set all ?

[mib]

Add negative test for -debugger-tune=sce.

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

void DwarfDebug::emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
   } else if (Value.isTargetIndexLocation()) {
     TargetIndexLocation Loc = Value.getTargetIndexLocation();
     // TODO TargetIndexLocation is a target-independent. Currently only the WebAssembly-specific
     // encoding is supported.
     DwarfExpr.addWasmLocation(Loc.Index, static_cast<uint64_t>(Loc.Offset));
       DwarfExpr.addExpression(std::move(ExprCursor));
       return;
   } else if (Value.isConstantFP()) {
-    if (AP.getDwarfVersion() >= 4 && AP.getDwarfDebug()->tuneForGDB()) {
+    if (AP.getDwarfVersion() >= 4 && (AP.getDwarfDebug()->tuneForGDB() ||
+                                      AP.getDwarfDebug()->tuneForLLDB())) {
       DwarfExpr.addConstantFP(Value.getConstantFP()->getValueAPF(), AP);
       return;
     } else if (Value.getConstantFP()
                    ->getValueAPF()
                    .bitcastToAPInt()
                    .getBitWidth() <= 64 /*bits*/)
       DwarfExpr.addUnsignedConstant(
           Value.getConstantFP()->getValueAPF().bitcastToAPInt());
     else

llvm/test/DebugInfo/X86/implicit_value-double.ll

 ;; This test checks for emission of DW_OP_implicit_value operation
 ;; for double type.
 
-; RUN: llc -debugger-tune=gdb -filetype=obj %s -o - | llvm-dwarfdump - | FileCheck %s
+; RUN: llc -debugger-tune=gdb -filetype=obj %s -o -  | llvm-dwarfdump - | FileCheck %s
+; RUN: llc -debugger-tune=lldb -filetype=obj %s -o - | llvm-dwarfdump - | FileCheck %s
 
 ; CHECK: .debug_info contents:
 ; CHECK: DW_TAG_variable
 ; CHECK-NEXT:  DW_AT_location        ({{.*}}
 ; CHECK-NEXT:                     [{{.*}}): DW_OP_implicit_value 0x8 0x1f 0x85 0xeb 0x51 0xb8 0x1e 0x09 0x40)
 ; CHECK-NEXT:  DW_AT_name    ("d")
 
+; RUN: llc -debugger-tune=sce -filetype=obj %s -o -  | llvm-dwarfdump - | FileCheck %s -check-prefix=SCE-CHECK
+
+; SCE-CHECK: .debug_info contents:
+; SCE-CHECK: DW_TAG_variable
+; SCE-CHECK-NEXT:  DW_AT_location        ({{.*}}
+; SCE-CHECK-NEXT:                     [{{.*}}): DW_OP_constu 0x40091eb851eb851f, DW_OP_stack_value)
+; SCE-CHECK-NEXT:  DW_AT_name    ("d")
+
 ;; Generated from: clang -ggdb -O1
 ;;int main() {
 ;;        double d = 3.14;
 ;;        printf("dummy\n");
 ;;        d *= d;
 ;;        return 0;
 ;;}
 

llvm/test/DebugInfo/X86/implicit_value-float.ll

 ;; This test checks for emission of DW_OP_implicit_value operation
 ;; for float type.
 
-; RUN: llc -debugger-tune=gdb -filetype=obj %s -o - | llvm-dwarfdump - | FileCheck %s
+; RUN: llc -debugger-tune=gdb -filetype=obj %s -o -  | llvm-dwarfdump - | FileCheck %s
+; RUN: llc -debugger-tune=lldb -filetype=obj %s -o - | llvm-dwarfdump - | FileCheck %s
 
 ; CHECK: .debug_info contents:
 ; CHECK: DW_TAG_variable
 ; CHECK-NEXT:  DW_AT_location        ({{.*}}
 ; CHECK-NEXT:                     [{{.*}}): DW_OP_implicit_value 0x4 0xc3 0xf5 0x48 0x40)
 ; CHECK-NEXT:  DW_AT_name    ("f")
 
+; RUN: llc -debugger-tune=sce -filetype=obj %s -o -  | llvm-dwarfdump - | FileCheck %s -check-prefix=SCE-CHECK
+
+; SCE-CHECK: .debug_info contents:
+; SCE-CHECK: DW_TAG_variable
+; SCE-CHECK-NEXT:  DW_AT_location        ({{.*}}
+; SCE-CHECK-NEXT:                     [{{.*}}): DW_OP_constu 0x4048f5c3, DW_OP_stack_value)
+; SCE-CHECK-NEXT:  DW_AT_name    ("f")
+
 ;; Generated from: clang -ggdb -O1
 ;;int main() {
 ;;        float f = 3.14f;
 ;;        printf("dummy\n");
 ;;        f *= f;
 ;;        return 0;
 ;;}
 ; ModuleID = 'implicit_value-float.c'

llvm/test/DebugInfo/X86/stack-value-piece.ll

 ; CHECK-NEXT:   DW_AT_location ([[I:0x[0-9a-f]+]]
 ; CHECK-NEXT:     [{{.*}}, {{.*}}): DW_OP_reg5 RDI, DW_OP_piece 0x4, DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4)
 ; CHECK-NEXT:   DW_AT_name ("r")
 ;
 ; CHECK: DW_TAG_subprogram
 ; CHECK:   DW_AT_name ("f")
 ; CHECK:   DW_TAG_variable
 ; CHECK-NEXT:   DW_AT_location ([[F:0x[0-9a-f]+]]
-; CHECK-NEXT:     [{{.*}}, {{.*}}): DW_OP_reg17 XMM0, DW_OP_piece 0x4, DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4
-; CHECK-NEXT:     [{{.*}}, {{.*}}): DW_OP_piece 0x4, DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4)
+; CHECK-NEXT:     [{{.*}}, {{.*}}): DW_OP_reg17 XMM0, DW_OP_piece 0x4, {{(DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4|DW_OP_implicit_value 0x4 0x00 0x00 0x00 0x00)}}
+; CHECK-NEXT:     [{{.*}}, {{.*}}): DW_OP_piece 0x4, {{(DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4|DW_OP_implicit_value 0x4 0x00 0x00 0x00 0x00)}})
 ; CHECK-NEXT:   DW_AT_name ("r")
 ;
 ; CHECK: .debug_loc contents:
 ; CHECK:      [[I]]:
 ; CHECK-NEXT:   ({{.*}}, {{.*}}): DW_OP_reg5 RDI, DW_OP_piece 0x4, DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4
 ; CHECK:      [[F]]:
-; CHECK-NEXT:   ({{.*}}, {{.*}}): DW_OP_reg17 XMM0, DW_OP_piece 0x4, DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4
+; CHECK-NEXT:   ({{.*}}, {{.*}}): DW_OP_reg17 XMM0, DW_OP_piece 0x4, {{DW_OP_lit0, DW_OP_stack_value, DW_OP_piece 0x4|DW_OP_implicit_value 0x4 0x00 0x00 0x00 0x00}}
 
 source_filename = "stack-value-piece.c"
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.12.0"
 
 %struct.I = type { i32, i32 }
 %struct.F = type { float, float }