[DWARF][EntryValues] Emit GNU extensions in the case of DWARF 4 + SCE

[djtodoro]

Summary

Emit DWARF 5 call-site symbols even though DWARF 4 is set, only in the case of LLDB tuning.

This patch addresses PR46643.

[probinson]

Thanks! This will keep the debugger folks off my case. :-)

[djtodoro]

In D83463#2141678, @probinson wrote:

Thanks! This will keep the debugger folks off my case. :-)

:D

Thanks for the review!

[djtodoro]

• Rebase on top of D83462

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
 
   if (!ContextCU->includeMinimalInlineScopes())
     ContextCU->addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
   if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
     ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 }
 
 bool DwarfCompileUnit::useGNUAnalogForDwarf5Feature() const {
-  return DD->getDwarfVersion() == 4 && DD->tuneForGDB();
+  return DD->getDwarfVersion() == 4 && !DD->tuneForLLDB();
 }
 
 dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUTag(dwarf::Tag Tag) const {
   if (!useGNUAnalogForDwarf5Feature())
     return Tag;
   switch (Tag) {
   case dwarf::DW_TAG_call_site:
     return dwarf::DW_TAG_GNU_call_site;

llvm/test/DebugInfo/MIR/X86/call-site-gnu-vs-dwarf5-attrs.mir

-# Test the call site encoding in DWARF5 vs GNU extensions.
-#
-# === DWARF4, tune for gdb ===
+## Test the call site encoding in DWARF5 vs GNU extensions.
+
+## === DWARF4, tune for gdb ===
 # RUN: llc -emit-call-site-info -dwarf-version 4 -debugger-tune=gdb -filetype=obj \
 # RUN:     -mtriple=x86_64-unknown-unknown -start-after=machineverifier -o - %s  \
 # RUN:     | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-GNU -implicit-check-not=DW_AT_call
-#
+
 # === DWARF5, tune for gdb ===
 # RUN: llc -dwarf-version 5 -debugger-tune=gdb -emit-call-site-info -filetype=obj \
 # RUN:     -mtriple=x86_64-unknown-unknown -start-after=machineverifier -o - %s  \
 # RUN:     | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-DWARF5 -implicit-check-not=DW_AT_call
-#
-# === DWARF4, tune for lldb ===
+
+## === DWARF4, tune for lldb ===
 # RUN: llc -dwarf-version 4 -debugger-tune=lldb -emit-call-site-info -filetype=obj \
 # RUN:     -mtriple=x86_64-unknown-unknown -start-after=machineverifier -o - %s   \
 # RUN:     | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-DWARF5 -implicit-check-not=DW_AT_call
-#
-# === DWARF5, tune for lldb ===
+
+## === DWARF5, tune for lldb ===
 # RUN: llc -dwarf-version 5 -debugger-tune=lldb -emit-call-site-info -filetype=obj \
 # RUN:     -mtriple=x86_64-unknown-unknown -start-after=machineverifier -o - %s   \
 # RUN:     | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-DWARF5 -implicit-check-not=DW_AT_call
-#
+
+## === DWARF4, tune for sce ===
+# RUN: llc -emit-call-site-info -dwarf-version 4 -filetype=obj -debugger-tune=sce \
+# RUN:     -emit-debug-entry-values -debug-entry-values -mtriple=x86_64-unknown-unknown \
+# RUN:     -start-after=machineverifier -o - %s | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-GNU
+
+## === DWARF5, tune for sce ===
 # RUN: llc -emit-call-site-info -dwarf-version 5 -filetype=obj -debugger-tune=sce \
 # RUN:     -emit-debug-entry-values -debug-entry-values -mtriple=x86_64-unknown-unknown \
 # RUN:     -start-after=machineverifier -o - %s | llvm-dwarfdump - | FileCheck %s -check-prefixes=CHECK-DWARF5
-#
-# This is based on the following reproducer:
-#
-# extern void fn();
-# extern void fn2(int x);
-# extern int fn3();
-#
-# int fn1(int (*fn4) ()) {
-#   fn();
-#   fn2(5);
-#
-#   int x = (*fn4)();
-#   if (!x)
-#     return fn3();
-#   else
-#     return -1;
-# }
-#
-# Check GNU extensions:
-#
+
+## This is based on the following reproducer:
+##
+## extern void fn();
+## extern void fn2(int x);
+## extern int fn3();
+##
+## int fn1(int (*fn4) ()) {
+##   fn();
+##   fn2(5);
+##
+##   int x = (*fn4)();
+##   if (!x)
+##     return fn3();
+##   else
+##     return -1;
+## }
+
+## Check GNU extensions:
+
 # CHECK-GNU:        DW_TAG_subprogram
 # CHECK-GNU:          DW_AT_GNU_all_call_sites    (true)
 # CHECK-GNU:        DW_TAG_GNU_call_site
 # CHECK-GNU-NEXT:     DW_AT_abstract_origin
 # CHECK-GNU-NEXT:     DW_AT_low_pc
 # CHECK-GNU:          DW_TAG_GNU_call_site_parameter
 # CHECK-GNU-NEXT:       DW_AT_location
 # CHECK-GNU-NEXT:       DW_AT_GNU_call_site_value
 # CHECK-GNU:        DW_TAG_GNU_call_site
 # CHECK-GNU-NEXT:       DW_AT_GNU_call_site_target
 # CHECK-GNU-NEXT:       DW_AT_low_pc
 # CHECK-GNU:        DW_TAG_GNU_call_site
 # CHECK-GNU-NEXT:     DW_AT_abstract_origin
 # CHECK-GNU-NEXT:     DW_AT_GNU_tail_call
 # CHECK-GNU-NEXT:     DW_AT_low_pc
-#
-#
-# Check DWARF 5:
-#
+
+## Check DWARF 5:
+
 # CHECK-DWARF5:        DW_TAG_subprogram
 # CHECK-DWARF5:          DW_AT_call_all_calls    (true)
 # CHECK-DWARF5:        DW_TAG_call_site
 # CHECK-DWARF5-NEXT:     DW_AT_call_origin
 # CHECK-DWARF5-NEXT:     DW_AT_call_return_pc
 # CHECK-DWARF5:        DW_TAG_call_site
 # CHECK-DWARF5-NEXT:     DW_AT_call_origin
 # CHECK-DWARF5-NEXT:     DW_AT_call_return_pc
 # CHECK-DWARF5:          DW_TAG_call_site_parameter
 # CHECK-DWARF5-NEXT:       DW_AT_location
 # CHECK-DWARF5-NEXT:       DW_AT_call_value
 # CHECK-DWARF5:        DW_TAG_call_site
 # CHECK-DWARF5-NEXT:     DW_AT_call_target
 # CHECK-DWARF5-NEXT:     DW_AT_call_return_pc
 # CHECK-DWARF5:        DW_TAG_call_site
 # CHECK-DWARF5-NEXT:     DW_AT_call_origin
 # CHECK-DWARF5-NEXT:     DW_AT_call_tail_call
 # CHECK-DWARF5-NEXT:     DW_AT_call_pc
-#
+
 --- |
   ; ModuleID = 'call-site-attrs.c'
   source_filename = "call-site-attrs.c"
   target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
   target triple = "x86_64-unknown-linux-gnu"
   ; Function Attrs: nounwind uwtable
   define dso_local i32 @fn1(i32 (...)* nocapture %fn4) local_unnamed_addr !dbg !18 {
   entry: