[lldb] Move register info "augmentation" from gdb-remote into ABI

[labath]

Summary

Previously the ABI plugin exposed some "register infos" and the
gdb-remote code used those to fill in the missing bits. Now, the
"filling in" code is in the ABI plugin itself, and the gdb-remote code
just invokes that.

The motivation for this is two-fold:
a) the "augmentation" logic is useful outside of process gdb-remote. For

instance, it would allow us to avoid repeating the register number
definitions in minidump code.

b) It gives more implementation freedom to the ABI classes. Now that

these "register infos" are essentially implementation details, classes
can use other methods to obtain dwarf/eh_frame register numbers -- for
instance they can consult llvm MC layer.

Since the augmentation code was not currently tested anywhere, I took
the opportunity to create a simple test for it.

[clayborg]

lgtm

[jasonmolenda]

Good change, lgtm.

lldb/include/lldb/Target/ABI.h

virtual lldb::addr_t FixCodeAddress(lldb::addr_t pc) {
     // Some targets might use bits in a code address to indicate a mode switch.
     // ARM uses bit zero to signify a code address is thumb, so any ARM ABI
     // plug-ins would strip those bits.
     return pc;
   }
 
   llvm::MCRegisterInfo &GetMCRegisterInfo() { return *m_mc_register_info_up; }
 
-  virtual const RegisterInfo *GetRegisterInfoArray(uint32_t &count) = 0;
-
-  bool GetRegisterInfoByName(ConstString name, RegisterInfo &info);
-
-  bool GetRegisterInfoByKind(lldb::RegisterKind reg_kind, uint32_t reg_num,
-                             RegisterInfo &info);
+  virtual void AugmentRegisterInfo(RegisterInfo &info);
 
   virtual bool GetPointerReturnRegister(const char *&name) { return false; }
 
   static lldb::ABISP FindPlugin(lldb::ProcessSP process_sp, const ArchSpec &arch);
 
 protected:
   ABI(lldb::ProcessSP process_sp, std::unique_ptr<llvm::MCRegisterInfo> info_up)
       : m_process_wp(process_sp), m_mc_register_info_up(std::move(info_up)) {
     assert(m_mc_register_info_up && "ABI must have MCRegisterInfo");
   }
 
+  bool GetRegisterInfoByName(ConstString name, RegisterInfo &info);
+
+  virtual const RegisterInfo *GetRegisterInfoArray(uint32_t &count) = 0;
+
   /// Utility function to construct a MCRegisterInfo using the ArchSpec triple.
   /// Plugins wishing to customize the construction can construct the
   /// MCRegisterInfo themselves.
   static std::unique_ptr<llvm::MCRegisterInfo>
   MakeMCRegisterInfo(const ArchSpec &arch);
 
   lldb::ProcessWP m_process_wp;
   std::unique_ptr<llvm::MCRegisterInfo> m_mc_register_info_up;
 
 private:
   DISALLOW_COPY_AND_ASSIGN(ABI);
 };
 
 } // namespace lldb_private
 
 #endif // liblldb_ABI_h_

lldb/packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestTargetXMLArch.py

 from __future__ import print_function
 import lldb
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test.decorators import *
 from gdbclientutils import *
 
-class TestTargetXMLArch(GDBRemoteTestBase):
-
-    @skipIfXmlSupportMissing
-    @expectedFailureAll(archs=["i386"])
-    @skipIfRemote
-    def test(self):
-        """
-        Test lldb's parsing of the <architecture> tag in the target.xml register
-        description packet.
-        """
-        class MyResponder(MockGDBServerResponder):
-
-            def qXferRead(self, obj, annex, offset, length):
-                if annex == "target.xml":
-                    return """<?xml version="1.0"?>
-                        <target version="1.0">
-                          <architecture>i386:x86-64</architecture>
-                          <feature name="org.gnu.gdb.i386.core">
-    
-                         <flags id="i386_eflags" size="4">
-                         <field name="CF" start="0" end="0"/>
-                         <field name="" start="1" end="1"/>
-                         <field name="PF" start="2" end="2"/>
-                         <field name="AF" start="4" end="4"/>
-                         <field name="ZF" start="6" end="6"/>
-                         <field name="SF" start="7" end="7"/>
-                         <field name="TF" start="8" end="8"/>
-                         <field name="IF" start="9" end="9"/>
-                         <field name="DF" start="10" end="10"/>
-                         <field name="OF" start="11" end="11"/>
-                         <field name="NT" start="14" end="14"/>
-                         <field name="RF" start="16" end="16"/>
-                         <field name="VM" start="17" end="17"/>
-                         <field name="AC" start="18" end="18"/>
-                         <field name="VIF" start="19" end="19"/>
-                         <field name="VIP" start="20" end="20"/>
-                         <field name="ID" start="21" end="21"/>
-                         </flags>
-    
-                            <reg name="rax" bitsize="64" regnum="0" type="int" group="general"/>
-                            <reg name="rbx" bitsize="64" regnum="1" type="int" group="general"/>
-                            <reg name="rcx" bitsize="64" regnum="2" type="int" group="general"/>
-                            <reg name="rdx" bitsize="64" regnum="3" type="int" group="general"/>
-                            <reg name="rsi" bitsize="64" regnum="4" type="int" group="general"/>
-                            <reg name="rdi" bitsize="64" regnum="5" type="int" group="general"/>
-                            <reg name="rbp" bitsize="64" regnum="6" type="data_ptr" group="general"/>
-                            <reg name="rsp" bitsize="64" regnum="7" type="data_ptr" group="general"/>
-                            <reg name="r8" bitsize="64"  regnum="8" type="int" group="general"/>
-                            <reg name="r9" bitsize="64"  regnum="9" type="int" group="general"/>
-                            <reg name="r10" bitsize="64" regnum="10" type="int" group="general"/>
-                            <reg name="r11" bitsize="64" regnum="11" type="int" group="general"/>
-                            <reg name="r12" bitsize="64" regnum="12" type="int" group="general"/>
-                            <reg name="r13" bitsize="64" regnum="13" type="int" group="general"/>
-                            <reg name="r14" bitsize="64" regnum="14" type="int" group="general"/>
-                            <reg name="r15" bitsize="64" regnum="15" type="int" group="general"/>
-                            <reg name="rip" bitsize="64" regnum="16" type="code_ptr" group="general"/>
-                            <reg name="eflags" bitsize="32" regnum="17" type="i386_eflags" group="general"/>
-    
-                            <reg name="cs" bitsize="32" regnum="18" type="int" group="general"/>
-                            <reg name="ss" bitsize="32" regnum="19" type="int" group="general"/>
-                            <reg name="ds" bitsize="32" regnum="20" type="int" group="general"/>
-                            <reg name="es" bitsize="32" regnum="21" type="int" group="general"/>
-                            <reg name="fs" bitsize="32" regnum="22" type="int" group="general"/>
-                            <reg name="gs" bitsize="32" regnum="23" type="int" group="general"/>
-    
-                            <reg name="st0" bitsize="80" regnum="24" type="i387_ext" group="float"/>
-                            <reg name="st1" bitsize="80" regnum="25" type="i387_ext" group="float"/>
-                            <reg name="st2" bitsize="80" regnum="26" type="i387_ext" group="float"/>
-                            <reg name="st3" bitsize="80" regnum="27" type="i387_ext" group="float"/>
-                            <reg name="st4" bitsize="80" regnum="28" type="i387_ext" group="float"/>
-                            <reg name="st5" bitsize="80" regnum="29" type="i387_ext" group="float"/>
-                            <reg name="st6" bitsize="80" regnum="30" type="i387_ext" group="float"/>
-                            <reg name="st7" bitsize="80" regnum="31" type="i387_ext" group="float"/>
-    
-                            <reg name="fctrl" bitsize="32" regnum="32" type="int" group="float"/>
-                            <reg name="fstat" bitsize="32" regnum="33" type="int" group="float"/>
-                            <reg name="ftag"  bitsize="32" regnum="34" type="int" group="float"/>
-                            <reg name="fiseg" bitsize="32" regnum="35" type="int" group="float"/>
-                            <reg name="fioff" bitsize="32" regnum="36" type="int" group="float"/>
-                            <reg name="foseg" bitsize="32" regnum="37" type="int" group="float"/>
-                            <reg name="fooff" bitsize="32" regnum="38" type="int" group="float"/>
-                            <reg name="fop"   bitsize="32" regnum="39" type="int" group="float"/>
-                          </feature>
-                        </target>""", False
-                else:
-                    return None, False
 
-            def qC(self):
-                return "QC1"
 
-            def haltReason(self):
-                return "T05thread:00000001;06:9038d60f00700000;07:98b4062680ffffff;10:c0d7bf1b80ffffff;"
 
-            def readRegister(self, register):
-                regs = {0x0: "00b0060000610000",
-                        0xa: "68fe471c80ffffff",
-                        0xc: "60574a1c80ffffff",
-                        0xd: "18f3042680ffffff",
-                        0xe: "be8a4d7142000000",
-                        0xf: "50df471c80ffffff",
-                        0x10: "c0d7bf1b80ffffff" }
-                if register in regs:
-                    return regs[register]
-                else:
-                    return "0000000000000000"
 
+class TestTargetXMLArch(GDBRemoteTestBase):
+
+    @skipIfXmlSupportMissing
+    @expectedFailureAll(archs=["i386"])
+    @skipIfRemote
+    def test(self):
+        """
+        Test lldb's parsing of the <architecture> tag in the target.xml register
+        description packet.
+        """
         self.server.responder = MyResponder()
         interp = self.dbg.GetCommandInterpreter()
         result = lldb.SBCommandReturnObject()
         if self.TraceOn():
             self.runCmd("log enable gdb-remote packets")
             self.addTearDownHook(
                     lambda: self.runCmd("log disable gdb-remote packets"))
 
         target = self.dbg.CreateTarget('')
         self.assertEqual('', target.GetTriple())
         process = self.connect(target)
         if self.TraceOn():
             interp.HandleCommand("target list", result)
             print(result.GetOutput())
         self.assertTrue(target.GetTriple().startswith('x86_64-unknown-unknown'))
+
+    @skipIfXmlSupportMissing
+    @skipIfRemote
+    def test_register_augmentation(self):
+        """
+        Test that we correctly associate the register info with the eh_frame
+        register numbers.
+        """
+
+        target = self.createTarget("basic_eh_frame.yaml")
+        self.server.responder = MyResponder()
+
+        process = self.connect(target)
+        lldbutil.expect_state_changes(self, self.dbg.GetListener(), process,
+                [lldb.eStateStopped])
+        self.filecheck("image show-unwind -n foo", __file__,
+            "--check-prefix=UNWIND")
+# UNWIND: eh_frame UnwindPlan:
+# UNWIND: row[0]:    0: CFA=rsp+128 => rip=[CFA-8]

lldb/packages/Python/lldbsuite/test/functionalities/gdb_remote_client/basic_eh_frame.yaml

+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+  Entry:           0x0000000000401000
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x0000000000401000
+    AddressAlign:    0x0000000000000001
+    Content:         C3
+  - Name:            .eh_frame
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000000000402000
+    AddressAlign:    0x0000000000000008
+    Content:         1800000000000000017A5200017810011B0C070890010E80010000001000000020000000DCEFFFFF0100000000000000
+Symbols:
+  - Name:            .text
+    Type:            STT_SECTION
+    Section:         .text
+    Value:           0x0000000000401000
+  - Name:            .eh_frame
+    Type:            STT_SECTION
+    Section:         .eh_frame
+    Value:           0x0000000000402000
+  - Name:            _start
+    Binding:         STB_GLOBAL
+  - Name:            __bss_start
+    Section:         .eh_frame
+    Binding:         STB_GLOBAL
+    Value:           0x0000000000404000
+  - Name:            foo
+    Section:         .text
+    Binding:         STB_GLOBAL
+    Value:           0x0000000000401000
+  - Name:            _edata
+    Section:         .eh_frame
+    Binding:         STB_GLOBAL
+    Value:           0x0000000000404000
+  - Name:            _end
+    Section:         .eh_frame
+    Binding:         STB_GLOBAL
+    Value:           0x0000000000404000
+...

lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp

if (target_definition_sp) {
                                           GetTarget().GetArchitecture()) > 0) {
         return true;
       }
     }
   }
   return false;
 }
 
-// If the remote stub didn't give us eh_frame or DWARF register numbers for a
-// register, see if the ABI can provide them.
-// DWARF and eh_frame register numbers are defined as a part of the ABI.
-static void AugmentRegisterInfoViaABI(RegisterInfo &reg_info,
-                                      ConstString reg_name, ABISP abi_sp) {
-  if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM ||
-      reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM) {
-    if (abi_sp) {
-      RegisterInfo abi_reg_info;
-      if (abi_sp->GetRegisterInfoByName(reg_name, abi_reg_info)) {
-        if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindEHFrame] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindEHFrame] =
-              abi_reg_info.kinds[eRegisterKindEHFrame];
-        }
-        if (reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindDWARF] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindDWARF] =
-              abi_reg_info.kinds[eRegisterKindDWARF];
-        }
-        if (reg_info.kinds[eRegisterKindGeneric] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindGeneric] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindGeneric] =
-              abi_reg_info.kinds[eRegisterKindGeneric];
-        }
-      }
-    }
-  }
-}
-
 static size_t SplitCommaSeparatedRegisterNumberString(
     const llvm::StringRef &comma_separated_regiter_numbers,
     std::vector<uint32_t> &regnums, int base) {
   regnums.clear();
   std::pair<llvm::StringRef, llvm::StringRef> value_pair;
   value_pair.second = comma_separated_regiter_numbers;
   do {
     value_pair = value_pair.second.split(',');
if (m_gdb_comm.SendPacketAndWaitForResponse(packet, response, false) ==
           value_regs.push_back(LLDB_INVALID_REGNUM);
           reg_info.value_regs = value_regs.data();
         }
         if (!invalidate_regs.empty()) {
           invalidate_regs.push_back(LLDB_INVALID_REGNUM);
           reg_info.invalidate_regs = invalidate_regs.data();
         }
 
+        reg_info.name = reg_name.AsCString();
         // We have to make a temporary ABI here, and not use the GetABI because
         // this code gets called in DidAttach, when the target architecture
         // (and consequently the ABI we'll get from the process) may be wrong.
-        ABISP abi_to_use = ABI::FindPlugin(shared_from_this(), arch_to_use);
-
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_to_use);
+        if (ABISP abi_sp = ABI::FindPlugin(shared_from_this(), arch_to_use))
+          abi_sp->AugmentRegisterInfo(reg_info);
 
         m_register_info.AddRegister(reg_info, reg_name, alt_name, set_name);
       } else {
         break; // ensure exit before reg_num is incremented
       }
     } else {
       break;
     }
feature_node.ForEachChildElementWithName(
           reg_info.value_regs = value_regs.data();
         }
         if (!invalidate_regs.empty()) {
           invalidate_regs.push_back(LLDB_INVALID_REGNUM);
           reg_info.invalidate_regs = invalidate_regs.data();
         }
 
         ++cur_reg_num;
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_sp);
+        reg_info.name = reg_name.AsCString();
+        if (abi_sp)
+          abi_sp->AugmentRegisterInfo(reg_info);
         dyn_reg_info.AddRegister(reg_info, reg_name, alt_name, set_name);
 
         return true; // Keep iterating through all "reg" elements
       });
   return true;
 }
 
 } // namespace

lldb/source/Target/ABI.cpp

for (i = 0; i < count; ++i) {
         info = register_info_array[i];
         return true;
       }
     }
   }
   return false;
 }
 
-bool ABI::GetRegisterInfoByKind(RegisterKind reg_kind, uint32_t reg_num,
-                                RegisterInfo &info) {
-  if (reg_kind < eRegisterKindEHFrame || reg_kind >= kNumRegisterKinds)
-    return false;
-
-  uint32_t count = 0;
-  const RegisterInfo *register_info_array = GetRegisterInfoArray(count);
-  if (register_info_array) {
-    for (uint32_t i = 0; i < count; ++i) {
-      if (register_info_array[i].kinds[reg_kind] == reg_num) {
-        info = register_info_array[i];
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
 ValueObjectSP ABI::GetReturnValueObject(Thread &thread, CompilerType &ast_type,
                                         bool persistent) const {
   if (!ast_type.IsValid())
     return ValueObjectSP();
 
   ValueObjectSP return_valobj_sp;
 
   return_valobj_sp = GetReturnValueObjectImpl(thread, ast_type);
LLDB_LOG(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS),
              lookup_error);
     return nullptr;
   }
   std::unique_ptr<llvm::MCRegisterInfo> info_up(
       target->createMCRegInfo(triple));
   assert(info_up);
   return info_up;
 }
+
+void ABI::AugmentRegisterInfo(RegisterInfo &info) {
+  if (info.kinds[eRegisterKindEHFrame] != LLDB_INVALID_REGNUM &&
+      info.kinds[eRegisterKindDWARF] != LLDB_INVALID_REGNUM)
+    return;
+
+  RegisterInfo abi_info;
+  if (!GetRegisterInfoByName(ConstString(info.name), abi_info))
+    return;
+
+  if (info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM)
+    info.kinds[eRegisterKindEHFrame] = abi_info.kinds[eRegisterKindEHFrame];
+  if (info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM)
+    info.kinds[eRegisterKindDWARF] = abi_info.kinds[eRegisterKindDWARF];
+  if (info.kinds[eRegisterKindGeneric] == LLDB_INVALID_REGNUM)
+    info.kinds[eRegisterKindGeneric] = abi_info.kinds[eRegisterKindGeneric];
+}