[lldb] [llvm] [ptrauth] Teach LLVM & LLDB about LLVM_ptrauth_authentication_mode (PR #82272)

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Mon Feb 19 11:12:50 PST 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-debuginfo

Author: Jonas Devlieghere (JDevlieghere)

<details>
<summary>Changes</summary>

Teach LLVM & LLDB about `DW_AT_LLVM_ptrauth_authentication_mode`

---
Full diff: https://github.com/llvm/llvm-project/pull/82272.diff


4 Files Affected:

- (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp (+8-2) 
- (modified) llvm/include/llvm/BinaryFormat/Dwarf.def (+1) 
- (modified) llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp (+15) 
- (modified) llvm/test/tools/llvm-dwarfdump/AArch64/ptrauth.s (+16-10) 


``````````diff
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
index d4446befd83b05..4884374ef94729 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
@@ -316,8 +316,14 @@ void DWARFDIE::AppendTypeName(Stream &s) const {
         GetAttributeValueAsUnsigned(DW_AT_LLVM_ptrauth_extra_discriminator, 0);
     bool isaPointer =
         GetAttributeValueAsUnsigned(DW_AT_LLVM_ptrauth_isa_pointer, 0);
-    s.Printf("__ptrauth(%d, %d, 0x0%x, %d)", key, isAddressDiscriminated,
-             extraDiscriminator, isaPointer);
+    bool authenticatesNullValues = GetAttributeValueAsUnsigned(
+        DW_AT_LLVM_ptrauth_authenticates_null_values, 0);
+    unsigned authenticationMode =
+        GetAttributeValueAsUnsigned(DW_AT_LLVM_ptrauth_authentication_mode, 3);
+
+    s.Printf("__ptrauth(%d, %d, 0x0%x, %d, %d, %d)", key,
+             isAddressDiscriminated, extraDiscriminator, isaPointer,
+             authenticatesNullValues, authenticationMode);
     break;
   }
   default:
diff --git a/llvm/include/llvm/BinaryFormat/Dwarf.def b/llvm/include/llvm/BinaryFormat/Dwarf.def
index 3a08eeaa791aa6..e70b58d5ea50fc 100644
--- a/llvm/include/llvm/BinaryFormat/Dwarf.def
+++ b/llvm/include/llvm/BinaryFormat/Dwarf.def
@@ -611,6 +611,7 @@ HANDLE_DW_AT(0x3e06, LLVM_ptrauth_extra_discriminator, 0, LLVM)
 HANDLE_DW_AT(0x3e07, LLVM_apinotes, 0, APPLE)
 HANDLE_DW_AT(0x3e08, LLVM_ptrauth_isa_pointer, 0, LLVM)
 HANDLE_DW_AT(0x3e09, LLVM_ptrauth_authenticates_null_values, 0, LLVM)
+HANDLE_DW_AT(0x3e0a, LLVM_ptrauth_authentication_mode, 0, LLVM)
 
 // Apple extensions.
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp b/llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
index ef8ded8ebb66c1..05dee8a3d71298 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFTypePrinter.cpp
@@ -251,6 +251,21 @@ void DWARFTypePrinter::appendUnqualifiedNameAfter(
       optionsVec.push_back("isa-pointer");
     if (getValOrNull(DW_AT_LLVM_ptrauth_authenticates_null_values))
       optionsVec.push_back("authenticates-null-values");
+    if (auto AuthenticationMode =
+            D.find(DW_AT_LLVM_ptrauth_authentication_mode)) {
+      switch (*AuthenticationMode->getAsUnsignedConstant()) {
+      case 0:
+      case 1:
+        optionsVec.push_back("strip");
+        break;
+      case 2:
+        optionsVec.push_back("sign-and-strip");
+        break;
+      default:
+        // Default authentication policy
+        break;
+      }
+    }
     std::string options;
     for (const auto *option : optionsVec) {
       if (options.size())
diff --git a/llvm/test/tools/llvm-dwarfdump/AArch64/ptrauth.s b/llvm/test/tools/llvm-dwarfdump/AArch64/ptrauth.s
index d24a60d99bdac3..befd0fa86ef99c 100644
--- a/llvm/test/tools/llvm-dwarfdump/AArch64/ptrauth.s
+++ b/llvm/test/tools/llvm-dwarfdump/AArch64/ptrauth.s
@@ -23,7 +23,7 @@
 
 # CHECK: 0x0000004f:   DW_TAG_variable
 # CHECK:                 DW_AT_name      ("p3")
-# CHECK:                 DW_AT_type      (0x0000005a "void *__ptrauth(4, 1, 0x04d4, "authenticates-null-values")")
+# CHECK:                 DW_AT_type      (0x0000005a "void *__ptrauth(4, 1, 0x04d4, "authenticates-null-values,strip")")
 
 # CHECK: 0x0000005a:   DW_TAG_LLVM_ptrauth_type
 # CHECK:                 DW_AT_LLVM_ptrauth_key  (0x04)
@@ -31,11 +31,11 @@
 # CHECK:                 DW_AT_LLVM_ptrauth_extra_discriminator  (0x04d4)
 # CHECK:                 DW_AT_LLVM_ptrauth_authenticates_null_values    (true)
 
-# CHECK: 0x00000062:   DW_TAG_variable
+# CHECK: 0x00000063:   DW_TAG_variable
 # CHECK:                 DW_AT_name      ("p4")
-# CHECK:                 DW_AT_type      (0x0000006d "void *__ptrauth(4, 1, 0x04d5, "isa-pointer,authenticates-null-values")")
+# CHECK:                 DW_AT_type (0x0000006e "void *__ptrauth(4, 1, 0x04d5, "isa-pointer,authenticates-null-values,sign-and-strip")")
 
-# CHECK: 0x0000006d:   DW_TAG_LLVM_ptrauth_type
+# CHECK: 0x0000006e:   DW_TAG_LLVM_ptrauth_type
 # CHECK:                 DW_AT_LLVM_ptrauth_key  (0x04)
 # CHECK:                 DW_AT_LLVM_ptrauth_address_discriminated        (true)
 # CHECK:                 DW_AT_LLVM_ptrauth_extra_discriminator  (0x04d5)
@@ -44,7 +44,7 @@
 
 	.section	__TEXT,__text,regular,pure_instructions
 	.file	1 "/" "/tmp/p.c"
-	.comm	_p,8                            ; @p
+	.comm	_p,8,3                          ; @p
 	.section	__DWARF,__debug_abbrev,regular,debug
 Lsection_abbrev:
 	.byte	1                               ; Abbreviation Code
@@ -140,6 +140,8 @@ Lsection_abbrev:
 	.byte	5                               ; DW_FORM_data2
 	.ascii	"\211|"                         ; DW_AT_LLVM_ptrauth_authenticates_null_values
 	.byte	25                              ; DW_FORM_flag_present
+	.ascii	"\212|"                         ; DW_AT_LLVM_ptrauth_authentication_mode
+	.byte	11                              ; DW_FORM_data1
 	.byte	0                               ; EOM(1)
 	.byte	0                               ; EOM(2)
 	.byte	8                               ; Abbreviation Code
@@ -157,6 +159,8 @@ Lsection_abbrev:
 	.byte	25                              ; DW_FORM_flag_present
 	.ascii	"\211|"                         ; DW_AT_LLVM_ptrauth_authenticates_null_values
 	.byte	25                              ; DW_FORM_flag_present
+	.ascii	"\212|"                         ; DW_AT_LLVM_ptrauth_authentication_mode
+	.byte	11                              ; DW_FORM_data1
 	.byte	0                               ; EOM(1)
 	.byte	0                               ; EOM(2)
 	.byte	0                               ; EOM(3)
@@ -170,7 +174,7 @@ Ldebug_info_start0:
 .set Lset1, Lsection_abbrev-Lsection_abbrev ; Offset Into Abbrev. Section
 	.long	Lset1
 	.byte	8                               ; Address Size (in bytes)
-	.byte	1                               ; Abbrev [1] 0xb:0x6b DW_TAG_compile_unit
+	.byte	1                               ; Abbrev [1] 0xb:0x6d DW_TAG_compile_unit
 	.long	0                               ; DW_AT_producer
 	.short	12                              ; DW_AT_language
 	.long	1                               ; DW_AT_name
@@ -210,25 +214,27 @@ Ldebug_info_start0:
                                         ; DW_AT_external
 	.byte	1                               ; DW_AT_decl_file
 	.byte	1                               ; DW_AT_decl_line
-	.byte	7                               ; Abbrev [7] 0x5a:0x8 DW_TAG_LLVM_ptrauth_type
+	.byte	7                               ; Abbrev [7] 0x5a:0x9 DW_TAG_LLVM_ptrauth_type
 	.long	59                              ; DW_AT_type
 	.byte	4                               ; DW_AT_LLVM_ptrauth_key
                                         ; DW_AT_LLVM_ptrauth_address_discriminated
 	.short	1236                            ; DW_AT_LLVM_ptrauth_extra_discriminator
                                         ; DW_AT_LLVM_ptrauth_authenticates_null_values
-	.byte	5                               ; Abbrev [5] 0x62:0xb DW_TAG_variable
+	.byte	1                               ; DW_AT_LLVM_ptrauth_authentication_mode
+	.byte	5                               ; Abbrev [5] 0x63:0xb DW_TAG_variable
 	.long	21                              ; DW_AT_name
-	.long	109                             ; DW_AT_type
+	.long	110                             ; DW_AT_type
                                         ; DW_AT_external
 	.byte	1                               ; DW_AT_decl_file
 	.byte	1                               ; DW_AT_decl_line
-	.byte	8                               ; Abbrev [8] 0x6d:0x8 DW_TAG_LLVM_ptrauth_type
+	.byte	8                               ; Abbrev [8] 0x6e:0x9 DW_TAG_LLVM_ptrauth_type
 	.long	59                              ; DW_AT_type
 	.byte	4                               ; DW_AT_LLVM_ptrauth_key
                                         ; DW_AT_LLVM_ptrauth_address_discriminated
 	.short	1237                            ; DW_AT_LLVM_ptrauth_extra_discriminator
                                         ; DW_AT_LLVM_ptrauth_isa_pointer
                                         ; DW_AT_LLVM_ptrauth_authenticates_null_values
+	.byte	2                               ; DW_AT_LLVM_ptrauth_authentication_mode
 	.byte	0                               ; End Of Children Mark
 Ldebug_info_end0:
 	.section	__DWARF,__debug_str,regular,debug

``````````

</details>


https://github.com/llvm/llvm-project/pull/82272


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