Generate runtime debug info with source locations

4 files changed, 67 insertions, 22 deletions

diff --git a/pkg/lang/compiler/compiler.go b/pkg/lang/compiler/compiler.go
index b08a215..b1d4dfb 100644
--- a/pkg/lang/compiler/compiler.go
+++ b/pkg/lang/compiler/compiler.go
@@ -70,6 +70,8 @@ func (comp *Compiler) Compile() (modules.Module, error) {
 }
 
 func (comp *Compiler) compileStmt(t *code.Builder, stmt ast.Stmt) error {
+	startPc := t.Len()
+
 	var err error
 	switch stmt.Kind {
 	case ast.StmtKindEmpty:
@@ -119,15 +121,24 @@ func (comp *Compiler) compileStmt(t *code.Builder, stmt ast.Stmt) error {
 	}
 
 	// Wrap errors in a compiler error, if it's not already one.
-	if err != nil && !isCompilerError(err) {
-		err = Error{
-			Module: comp.name,
-			Loc:    stmt.At,
-			Err:    err,
+	if err != nil {
+		if !isCompilerError(err) {
+			err = Error{
+				Module: comp.name,
+				Loc:    stmt.At,
+				Err:    err,
+			}
 		}
+		return err
 	}
 
-	return err
+	// Add debug info if needed.
+	endPc := t.Len()
+	if startPc != endPc {
+		t.AddDebugInfo(startPc, endPc-1, stmt.At)
+	}
+
+	return nil
 }
 
 func (comp *Compiler) compileUseStmt(t *code.Builder, stmt ast.StmtUse) error {
@@ -645,6 +656,8 @@ func (comp *Compiler) compileExprStmt(t *code.Builder, exprStmt ast.StmtExpr) er
 }
 
 func (comp *Compiler) compileExpr(t *code.Builder, expr ast.Expr) error {
+	startPc := t.Len()
+
 	var err error
 	switch expr.Kind {
 	case ast.ExprKindBinary:
@@ -683,15 +696,24 @@ func (comp *Compiler) compileExpr(t *code.Builder, expr ast.Expr) error {
 	}
 
 	// If the error was not a compiler error, we need to wrap it in one.
-	if err != nil && !isCompilerError(err) {
-		err = Error{
-			Module: comp.name,
-			Loc:    expr.At,
-			Err:    err,
+	if err != nil {
+		if !isCompilerError(err) {
+			err = Error{
+				Module: comp.name,
+				Loc:    expr.At,
+				Err:    err,
+			}
 		}
+
+		return err
 	}
 
-	return err
+	endPc := t.Len()
+	if startPc != endPc {
+		t.AddDebugInfo(startPc, endPc-1, expr.At)
+	}
+
+	return nil
 }
 
 func (comp *Compiler) compileBinaryExpr(t *code.Builder, expr ast.ExprBinary) error {
diff --git a/pkg/lang/vm/code/builder.go b/pkg/lang/vm/code/builder.go
index f413ba1..618608a 100644
--- a/pkg/lang/vm/code/builder.go
+++ b/pkg/lang/vm/code/builder.go
@@ -2,6 +2,7 @@ package code
 
 import (
 	"encoding/binary"
+	"jinx/pkg/libs/source"
 	"math"
 )
 
@@ -76,6 +77,7 @@ func (b *Builder) AppendBuilder(other Builder) error {
 	}
 
 	b.AppendRaw(other.code)
+	b.debugInfo.AppendOther(other.debugInfo)
 
 	return nil
 }
@@ -114,6 +116,10 @@ func (b *Builder) EndLine() {
 	b.debugInfo.AppendLine(b.Len()-1, b.currentLine)
 }
 
+func (b *Builder) AddDebugInfo(fromPc, toPc int, loc source.Loc) {
+	b.debugInfo.FillInfo(fromPc, toPc, loc)
+}
+
 func (b *Builder) SetInt(at int, x int64) {
 	binary.LittleEndian.PutUint64(b.code[at:], uint64(x))
 }
diff --git a/pkg/lang/vm/code/debug.go b/pkg/lang/vm/code/debug.go
index ebf0ea1..efb788c 100644
--- a/pkg/lang/vm/code/debug.go
+++ b/pkg/lang/vm/code/debug.go
@@ -1,16 +1,19 @@
 package code
 
-import "jinx/pkg/libs/rangemap"
+import (
+	"jinx/pkg/libs/rangemap"
+	"jinx/pkg/libs/source"
+)
 
 type DebugInfo struct {
 	file     string
-	pcToLine rangemap.RangeMap[int]
+	pcToLine rangemap.RangeMap[source.Loc]
 }
 
 func NewDebugInfo(file string) DebugInfo {
 	return DebugInfo{
 		file:     file,
-		pcToLine: rangemap.New[int](),
+		pcToLine: rangemap.New[source.Loc](),
 	}
 }
 
@@ -18,14 +21,22 @@ func (di *DebugInfo) File() string {
 	return di.file
 }
 
-func (di *DebugInfo) PCToLine(pc int) int {
-	line := di.pcToLine.Get(pc)
-	if line == nil {
-		return -1
+func (di *DebugInfo) PCToLoc(pc int) (source.Loc, bool) {
+	loc := di.pcToLine.Get(pc)
+	if loc == nil {
+		return source.Loc{}, false
 	}
-	return *line
+	return *loc, true
 }
 
 func (di *DebugInfo) AppendLine(uptoPc, line int) {
-	di.pcToLine.AppendToLast(uptoPc, line)
+	di.pcToLine.AppendToLast(uptoPc, source.Loc{Row: line, Col: 0})
+}
+
+func (di *DebugInfo) FillInfo(from, to int, loc source.Loc) {
+	di.pcToLine.Fill(from, to, loc)
+}
+
+func (di *DebugInfo) AppendOther(other DebugInfo) {
+	di.pcToLine.AppendRanges(other.pcToLine)
 }
diff --git a/pkg/lang/vm/vm.go b/pkg/lang/vm/vm.go
index 4d4d5ca..b18e7cb 100644
--- a/pkg/lang/vm/vm.go
+++ b/pkg/lang/vm/vm.go
@@ -121,10 +121,16 @@ func (vm *VM) executeModule(moduleID int) error {
 		vm.advancePC(advance)
 
 		if decision, err := vm.step(code, op); err != nil {
+			loc, ok := code.Debug().PCToLoc(vm.pc())
+			line := loc.Row
+			if !ok {
+				line = -1
+			}
+
 			return Error{
 				Pos:    vm.pos,
 				Module: module.Name(),
-				Line:   code.Debug().PCToLine(vm.pc()),
+				Line:   line,
 				Err:    err,
 			}
 		} else if decision == stepDecisionHalt {