stack/unwind: Simplify for loop

Signed-off-by: Sumera Priyadarsini <[email protected]>
parca-dev · Feb 11, 2024 · 156c451 · 156c451
1 parent 00b7582
commit 156c451
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Showing 4 changed files with 34 additions and 29 deletions.
diff --git a/internal/dwarf/frame/table.go b/internal/dwarf/frame/table.go
@@ -321,7 +321,7 @@ func executeDWARFInstruction(ctx *Context) error {
 
  fn, err := lookupFunc(instruction, ctx)
  if err != nil {
- return fmt.Errorf(" DWARF CFA rule is not valid. This should never happen :%w", err)
+ return fmt.Errorf("DWARF CFA rule is not valid. This should never happen :%w", err)
  }
  fn(ctx)
 

diff --git a/pkg/stack/unwind/compact_unwind_table.go b/pkg/stack/unwind/compact_unwind_table.go
@@ -158,14 +158,14 @@ func BuildCompactUnwindTable(fdes frame.FrameDescriptionEntries, arch elf.Machin
  return CompactUnwindTable{}, err
  }
 
- var err2 error
-
- for insCtx, err1 := frameContext.Next(); frameContext.HasNext(); insCtx, err2 = frameContext.Next() {
- if err1 != nil {
- return CompactUnwindTable{}, err1
+ for {
+ insCtx, err := frameContext.Next()
+ if err != nil {
+ return CompactUnwindTable{}, err
  }
- if err2 != nil {
- return CompactUnwindTable{}, err2
+
+ if !frameContext.HasNext() {
+ break
  }
 
  row := unwindTableRow(insCtx)
@@ -175,7 +175,6 @@ func BuildCompactUnwindTable(fdes frame.FrameDescriptionEntries, arch elf.Machin
  }
  table = append(table, compactRow)
  }
-
  lastFunctionPc = fde.End()
  }
  // Add a synthetic row at the end of the unwind table. It is fine

diff --git a/pkg/stack/unwind/unwind_table.go b/pkg/stack/unwind/unwind_table.go
@@ -106,14 +106,16 @@ func (ptb *UnwindTableBuilder) PrintTable(writer io.Writer, path string, compact
  if err != nil {
  return err
  }
- var err2 error
- for insCtx, err1 := frameContext.Next(); frameContext.HasNext(); insCtx, err2 = frameContext.Next() {
- if err1 != nil {
- return err1
+
+ for {
+ insCtx, err := frameContext.Next()
+ if err != nil {
+ return err
  }
- if err2 != nil {
- return err2
+ if !frameContext.HasNext() {
+ break
  }
+
  unwindRow := unwindTableRow(insCtx)
 
  if unwindRow == nil {
@@ -241,13 +243,15 @@ func BuildUnwindTable(fdes frame.FrameDescriptionEntries) (UnwindTable, error) {
  if err != nil {
  return UnwindTable{}, err
  }
- var err2 error
- for insCtx, err1 := frameContext.Next(); frameContext.HasNext(); insCtx, err2 = frameContext.Next() {
- if err1 != nil {
- return UnwindTable{}, err1
+
+ for {
+ insCtx, err := frameContext.Next()
+ if err != nil {
+ return UnwindTable{}, err
  }
- if err2 != nil {
- return UnwindTable{}, err2
+
+ if !frameContext.HasNext() {
+ break
  }
  table = append(table, *unwindTableRow(insCtx))
  }

diff --git a/pkg/stack/unwind/unwind_table_test.go b/pkg/stack/unwind/unwind_table_test.go
@@ -15,7 +15,6 @@
 package unwind
 
 import (
- "fmt"
  "testing"
 
  "github.com/stretchr/testify/require"
@@ -81,16 +80,19 @@ func benchmarkParsingDWARFUnwindInformation(b *testing.B, executable string) {
  for _, fde := range fdes {
  frameContext, err := frame.ExecuteDWARFProgram(fde, unwindContext)
  if err != nil {
- panic(fmt.Sprintf("unable to evaluate DWARF unwind code. Error: %s", err))
+ b.Fail()
  }
- var err2 error
- for insCtx, err1 := frameContext.Next(); frameContext.HasNext(); insCtx, err2 = frameContext.Next() {
- if err1 != nil {
- panic(fmt.Sprintf("unable to evaluate DWARF unwind code. Error: %s", err1))
+
+ for {
+ insCtx, err := frameContext.Next()
+ if err != nil {
+ b.Fail()
  }
- if err2 != nil {
- panic(fmt.Sprintf("unable to evaluate DWARF unwind code. Error: %s", err2))
+
+ if !frameContext.HasNext() {
+ break
  }
+
  unwindRow := unwindTableRow(insCtx)
  if unwindRow.RBP.Rule == frame.RuleUndefined || unwindRow.RBP.Offset == 0 {
  // u