service,terminal: support logical breakpoints (#1742)

Changes CreateBreakpoint to create a logical breakpoint when multiple
addresses are specified, FindLocation and the api.Location type to
return logical locations and the cli to support logical breakpoints.

pkg/terminal/command.go

@@ -4,6 +4,7 @@ package terminal
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"fmt"
 	"go/parser"
@@ -1188,6 +1189,9 @@ func clearAll(t *Term, ctx callContext, args string) error {
 		}
 		locPCs = make(map[uint64]struct{})
 		for _, loc := range locs {
+			for _, pc := range loc.PCs {
+				locPCs[pc] = struct{}{}
+			}
 			locPCs[loc.PC] = struct{}{}
 		}
 	}
@@ -1297,6 +1301,7 @@ func setBreakpoint(t *Term, ctx callContext, tracepoint bool, argstr string) err
 	}
 	for _, loc := range locs {
 		requestedBp.Addr = loc.PC
+		requestedBp.Addrs = loc.PCs
 
 		bp, err := t.client.CreateBreakpoint(requestedBp)
 		if err != nil {
@@ -2222,9 +2227,24 @@ func formatBreakpointName(bp *api.Breakpoint, upcase bool) string {
 }
 
 func formatBreakpointLocation(bp *api.Breakpoint) string {
+	var out bytes.Buffer
+	if len(bp.Addrs) > 0 {
+		for i, addr := range bp.Addrs {
+			if i == 0 {
+				fmt.Fprintf(&out, "%#x", addr)
+			} else {
+				fmt.Fprintf(&out, ",%#x", addr)
+			}
+		}
+	} else {
+		// In case we are connecting to an older version of delve that does not return the Addrs field.
+		fmt.Fprintf(&out, "%#x", bp.Addr)
+	}
+	fmt.Fprintf(&out, " for ")
 	p := ShortenFilePath(bp.File)
 	if bp.FunctionName != "" {
-		return fmt.Sprintf("%#v for %s() %s:%d", bp.Addr, bp.FunctionName, p, bp.Line)
+		fmt.Fprintf(&out, "%s() ", bp.FunctionName)
 	}
-	return fmt.Sprintf("%#v for %s:%d", bp.Addr, p, bp.Line)
+	fmt.Fprintf(&out, "%s:%d", p, bp.Line)
+	return out.String()
 }

service/api/types.go

@@ -126,11 +126,16 @@ type Thread struct {
 }
 
 // Location holds program location information.
+// In most cases a Location object will represent a physical location, with
+// a single PC address held in the PC field.
+// FindLocations however returns logical locations that can either have
+// multiple PC addresses each (due to inlining) or no PC address at all.
 type Location struct {
 	PC       uint64    `json:"pc"`
 	File     string    `json:"file"`
 	Line     int       `json:"line"`
 	Function *Function `json:"function,omitempty"`
+	PCs      []uint64  `json:"pcs,omitempty"`
 }
 
 // Stackframe describes one frame in a stack trace.

service/debugger/debugger.go

@@ -446,6 +446,8 @@ func (d *Debugger) CreateBreakpoint(requestedBp *api.Breakpoint) (*api.Breakpoin
 		addrs, err = proc.FindFileLocation(d.target, fileName, requestedBp.Line)
 	case len(requestedBp.FunctionName) > 0:
 		addrs, err = proc.FindFunctionLocation(d.target, requestedBp.FunctionName, requestedBp.Line)
+	case len(requestedBp.Addrs) > 0:
+		addrs = requestedBp.Addrs
 	default:
 		addrs = []uint64{requestedBp.Addr}
 	}

service/debugger/locations.go

@@ -251,8 +251,8 @@ func (loc *RegexLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr st
 	r := make([]api.Location, 0, len(matches))
 	for i := range matches {
 		addrs, _ := proc.FindFunctionLocation(d.target, matches[i], 0)
-		for _, addr := range addrs {
-			r = append(r, api.Location{PC: addr})
+		if len(addrs) > 0 {
+			r = append(r, addressesToLocation(addrs))
 		}
 	}
 	return r, nil
@@ -283,7 +283,7 @@ func (loc *AddrLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr str
 			if err != nil {
 				return nil, err
 			}
-			return []api.Location{{PC: uint64(pc)}}, nil
+			return []api.Location{{PC: pc}}, nil
 		default:
 			return nil, fmt.Errorf("wrong expression kind: %v", v.Kind)
 		}
@@ -389,25 +389,21 @@ func (loc *NormalLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr s
 				return []api.Location{{File: candidateFiles[0], Line: loc.LineOffset}}, nil
 			}
 		}
-	} else { // len(candidateFUncs) == 1
+	} else { // len(candidateFuncs) == 1
 		addrs, err = proc.FindFunctionLocation(d.target, candidateFuncs[0], loc.LineOffset)
 	}
 
 	if err != nil {
 		return nil, err
 	}
-	return addressesToLocations(addrs), nil
+	return []api.Location{addressesToLocation(addrs)}, nil
 }
 
-func addressesToLocations(addrs []uint64) []api.Location {
-	if addrs == nil {
-		return nil
+func addressesToLocation(addrs []uint64) api.Location {
+	if len(addrs) <= 0 {
+		return api.Location{}
 	}
-	r := make([]api.Location, len(addrs))
-	for i := range addrs {
-		r[i] = api.Location{PC: addrs[i]}
-	}
-	return r
+	return api.Location{PC: addrs[0], PCs: addrs}
 }
 
 func (loc *OffsetLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr string, includeNonExecutableLines bool) ([]api.Location, error) {
@@ -427,7 +423,7 @@ func (loc *OffsetLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr s
 			return []api.Location{{File: file, Line: line + loc.Offset}}, nil
 		}
 	}
-	return addressesToLocations(addrs), err
+	return []api.Location{addressesToLocation(addrs)}, err
 }
 
 func (loc *LineLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr string, includeNonExecutableLines bool) ([]api.Location, error) {
@@ -444,5 +440,5 @@ func (loc *LineLocationSpec) Find(d *Debugger, scope *proc.EvalScope, locStr str
 			return []api.Location{{File: file, Line: loc.Line}}, nil
 		}
 	}
-	return addressesToLocations(addrs), err
+	return []api.Location{addressesToLocation(addrs)}, err
 }

service/rpc2/server.go

@@ -231,6 +231,9 @@ type CreateBreakpointOut struct {
 // the breakpoint will be created on the specified function:line
 // location.
 //
+// - If arg.Breakpoint.Addrs is filled it will create a logical breakpoint
+// corresponding to all specified addresses.
+//
 // - Otherwise the value specified by arg.Breakpoint.Addr will be used.
 func (s *RPCServer) CreateBreakpoint(arg CreateBreakpointIn, out *CreateBreakpointOut) error {
 	createdbp, err := s.debugger.CreateBreakpoint(&arg.Breakpoint)
@@ -577,7 +580,7 @@ type FindLocationOut struct {
 	Locations []api.Location
 }
 
-// FindLocation returns concrete location information described by a location expression
+// FindLocation returns concrete location information described by a location expression.
 //
 //  loc ::= <filename>:<line> | <function>[:<line>] | /<regex>/ | (+|-)<offset> | <line> | *<address>
 //  * <filename> can be the full path of a file or just a suffix