FpDebug: Added support for DW_AT_entry_pc. Implemented <func>.EntryPCAddress to return the entry-point.

components/fpdebug/fpdbgdwarf.pas

@@ -496,6 +496,7 @@ type
   TFpValueDwarfSubroutine = class(TFpValueDwarf)
   protected
     function IsValidTypeCast: Boolean; override;
+    function GetEntryPCAddress: TFpDbgMemLocation; override;
   end;
 {%endregion Value objects }
 
@@ -1045,6 +1046,8 @@ DECL = DW_AT_decl_column, DW_AT_decl_file, DW_AT_decl_line
     function GetValueObject: TFpValue; override;
     function GetValueAddress(AValueObj: TFpValueDwarf; out
       AnAddress: TFpDbgMemLocation): Boolean; override;
+    function GetEntryPCAddress(AValueObj: TFpValueDwarf; out
+      AnAddress: TFpDbgMemLocation): Boolean;
 
     property DbgInfo: TFpDwarfInfo read FDwarf;
     property ProcAddress: TDBGPtr read FAddress;
@@ -1190,6 +1193,16 @@ begin
   Result := False;
 end;
 
+function TFpValueDwarfSubroutine.GetEntryPCAddress: TFpDbgMemLocation;
+begin
+  Result := InvalidLoc;
+  if (FDataSymbol = nil) then
+    exit;
+  assert(FDataSymbol is TFpSymbolDwarfDataProc, 'TFpValueDwarfSubroutine.GetEntryPCAddress: FDataSymbol is TFpSymbolDwarfDataProc');
+  if not TFpSymbolDwarfDataProc(FDataSymbol).GetEntryPCAddress(Self, Result) then
+    Result := InvalidLoc;
+end;
+
 { TFpDwarfDefaultSymbolClassMap }
 
 class function TFpDwarfDefaultSymbolClassMap.GetExistingClassMap: PFpDwarfSymbolClassMap;
@@ -6278,6 +6291,45 @@ begin
   Result := IsValidLoc(AnAddress);
 end;
 
+function TFpSymbolDwarfDataProc.GetEntryPCAddress(AValueObj: TFpValueDwarf; out
+  AnAddress: TFpDbgMemLocation): Boolean;
+var
+  AttrData: TDwarfAttribData;
+  Addr: TDBGPtr;
+  Offs: QWord;
+  f: Cardinal;
+begin
+  AnAddress := InvalidLoc;
+  Offs := 0;
+
+  if InformationEntry.GetAttribData(DW_AT_entry_pc, AttrData) then begin
+    f := AttrData.InformationEntry.AttribForm[AttrData.Idx];
+    if f = DW_FORM_addr then begin
+      Result := InformationEntry.ReadAddressValue(AttrData, Addr);
+      if Result then
+        AnAddress := TargetLoc(Addr);
+      exit;
+    end
+    else
+    // DWARF 5: DW_AT_entry_pc can be an unsigned offset to DW_AT_low_pc
+    if f in [DW_FORM_data1, DW_FORM_data2, DW_FORM_data4, DW_FORM_data8, DW_FORM_sdata, DW_FORM_udata] then begin
+      Result := InformationEntry.ReadValue(AttrData, Offs);
+      if not Result then
+        exit;
+    end
+    else
+      exit(False); // error
+  end;
+
+  if InformationEntry.GetAttribData(DW_AT_low_pc, AttrData) then
+    if InformationEntry.ReadAddressValue(AttrData, Addr) then
+      {$PUSH}{$R-}{$Q-}
+      AnAddress := TargetLoc(Addr + Offs);
+      {$POP}
+  //DW_AT_ranges
+  Result := IsValidLoc(AnAddress);
+end;
+
 function TFpSymbolDwarfDataProc.StateMachineValid: Boolean;
 var
   SM1, SM2: TDwarfLineInfoStateMachine;

components/fpdebug/fpdbginfo.pas

@@ -134,6 +134,7 @@ type
     function DoGetSize(out ASize: TFpDbgValueSize): Boolean; virtual;
     function GetDataAddress: TFpDbgMemLocation;  virtual;
     function GetDerefAddress: TFpDbgMemLocation;  virtual;
+    function GetEntryPCAddress: TFpDbgMemLocation; virtual;
     function GetDataSize: TFpDbgValueSize;  virtual;
 
     function GetHasBounds: Boolean; virtual;
@@ -180,6 +181,7 @@ type
     property Address: TFpDbgMemLocation read GetAddress;
     property DataAddress: TFpDbgMemLocation read GetDataAddress; //
     property DerefAddress: TFpDbgMemLocation read GetDerefAddress; //
+    property EntryPCAddress: TFpDbgMemLocation read GetEntryPCAddress;
     property DataSize: TFpDbgValueSize read GetDataSize;
 
     property HasBounds: Boolean  read GetHasBounds;
@@ -1035,6 +1037,11 @@ begin
   Result := 0;
 end;
 
+function TFpValue.GetEntryPCAddress: TFpDbgMemLocation;
+begin
+  Result := InvalidLoc;
+end;
+
 procedure TFpValue.Reset;
 begin
   FEvalFlags := [];

components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas

@@ -898,7 +898,7 @@ begin
 
     // check params
 
-    ProcAddress := AFunctionValue.DataAddress;
+    ProcAddress := AFunctionValue.EntryPCAddress;
     if not IsReadableLoc(ProcAddress) then begin
       DebugLn(['Error proc addr']);
       AnError := CreateError(fpErrAnyError, ['Unable to calculate function address']);