Show register names in DWARF unwind info.

Register context information was already being passed into the DWARFDebugFrame code that dumps unwind information but it wasn't being used. This change adds the ability to dump registers names of a valid MC register context was passed in and if it knows about the register. Updated the tests to use the newly returned register names.

Differential Revision: https://reviews.llvm.org/D88767

Author: clayborg

llvm/lib/DebugInfo/DWARF/DWARFDebugFrame.cpp

@@ -12,6 +12,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataExtractor.h"
@@ -29,6 +30,18 @@
 using namespace llvm;
 using namespace dwarf;
 
+static void printRegister(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH,
+                          unsigned RegNum) {
+  if (MRI) {
+    if (Optional<unsigned> LLVMRegNum = MRI->getLLVMRegNum(RegNum, IsEH)) {
+      if (const char *RegName = MRI->getName(*LLVMRegNum)) {
+        OS << RegName;
+        return;
+      }
+    }
+  }
+  OS << "reg" << RegNum;
+}
 
 // See DWARF standard v3, section 7.23
 const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
@@ -268,7 +281,8 @@ void CFIProgram::printOperand(raw_ostream &OS, const MCRegisterInfo *MRI,
       OS << format(" %" PRId64 "*data_alignment_factor" , Operand);
     break;
   case OT_Register:
-    OS << format(" reg%" PRId64, Operand);
+    OS << ' ';
+    printRegister(OS, MRI, IsEH, Operand);
     break;
   case OT_Expression:
     assert(Instr.Expression && "missing DWARFExpression object");

llvm/test/DebugInfo/RISCV/eh-frame.s

@@ -26,7 +26,7 @@ func:
 # FDECFIEncoding and should be DW_EH_PE_pcrel | DW_EH_PE_sdata4 (0x1b).
 
 # CHECK:   Augmentation data:     1B
-# CHECK:   DW_CFA_def_cfa: reg2 +0
+# CHECK:   DW_CFA_def_cfa: X2 +0
 #
 # CHECK: 00000014 00000010 00000018 FDE cie=00000000 pc=00000000...00000004
 # CHECK:   DW_CFA_nop:

llvm/test/DebugInfo/dwarfdump-debug-frame-simple.test

@@ -5,8 +5,8 @@
 
 ; FRAMES: 00000000 00000010 ffffffff CIE
 ; FRAMES: Version: 1
-; FRAMES:      DW_CFA_def_cfa: reg4 +4
-; FRAMES-NEXT: DW_CFA_offset: reg8 -4
+; FRAMES:      DW_CFA_def_cfa: ESP +4
+; FRAMES-NEXT: DW_CFA_offset: EIP -4
 ; FRAMES-NEXT: DW_CFA_nop:
 ; FRAMES-NEXT: DW_CFA_nop:
 
@@ -18,9 +18,9 @@
 ; FRAMES: 00000028 00000014 00000000 FDE cie=00000000 pc=00000030...00000080
 ; FRAMES:      DW_CFA_advance_loc: 1
 ; FRAMES-NEXT: DW_CFA_def_cfa_offset: +8
-; FRAMES-NEXT: DW_CFA_offset: reg5 -8
+; FRAMES-NEXT: DW_CFA_offset: EBP -8
 ; FRAMES-NEXT: DW_CFA_advance_loc: 2
-; FRAMES-NEXT: DW_CFA_def_cfa_register: reg5
+; FRAMES-NEXT: DW_CFA_def_cfa_register: EBP
 
 ; FRAMES-NOT: CIE
 ; FRAMES-NOT: FDE

llvm/test/MC/ELF/cfi-restore-extended.s

@@ -6,12 +6,11 @@ f:
   nop
 // CHECK: DW_CFA_advance_loc: 1
   .cfi_restore %rbp
-// CHECK-NEXT: DW_CFA_restore: reg6
+// CHECK-NEXT: DW_CFA_restore: RBP
   nop
 // CHECK-NEXT: DW_CFA_advance_loc: 1
   .cfi_restore 89
 // CHECK-NEXT: DW_CFA_restore_extended: reg89
 // CHECK-NEXT: DW_CFA_nop:
   nop
   .cfi_endproc
-

llvm/test/MC/Mips/eh-frame.s

@@ -66,7 +66,7 @@ func:
 // DWARF32_PIC-NEXT: Augmentation data: 1B
 //                                      ^^ fde pointer encoding: DW_EH_PE_pcrel | DW_EH_PE_sdata4
 // DWARF32-EMPTY:
-// DWARF32-NEXT:     DW_CFA_def_cfa_register: reg29
+// DWARF32-NEXT:     DW_CFA_def_cfa_register: SP_64
 //
 // DWARF32_ABS: 00000014 00000010 00000018 FDE cie=00000000 pc=00000000...00000000
 // DWARF32_PIC: 00000014 00000010 00000018 FDE cie=00000000 pc=0000001c...0000001c
@@ -90,7 +90,7 @@ func:
 // DWARF64_PIC:      Augmentation data: 1B
 //                                      ^^ fde pointer encoding: DW_EH_PE_pcrel | DW_EH_PE_sdata4
 // DWARF64-EMPTY:
-// DWARF64-NEXT:     DW_CFA_def_cfa_register: reg29
+// DWARF64-NEXT:     DW_CFA_def_cfa_register: SP_64
 // DWARF64_PIC-NEXT: DW_CFA_nop:
 //
 // DWARF64_ABS:      00000014 00000018 00000018 FDE cie=00000000 pc=00000000...00000000

llvm/test/MC/X86/i386-darwin-frame-register.ll

@@ -11,7 +11,7 @@
 ; CHECK: .debug_frame contents:
 ; CHECK: ffffffff CIE
 ; CHECK-NOT: {{CIE|FDE}}
-; CHECK:   DW_CFA_def_cfa: reg4 +4
+; CHECK:   DW_CFA_def_cfa: ESP +4
 
 ; ModuleID = 'foo.c'
 target datalayout = "e-m:o-p:32:32-f64:32:64-f80:128-n8:16:32-S128"