// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package pgo contains the compiler-agnostic portions of PGO profile handling.
// Notably, parsing pprof profiles and serializing/deserializing from a custom
// intermediate representation.
package pgo

import (
	"errors"
	"fmt"
	"internal/profile"
	"io"
	"sort"
)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package pgo contains the compiler-agnostic portions of PGO profile handling.
// Notably, parsing pprof profiles and serializing/deserializing from a custom
// intermediate representation.
package pgo

// Profile contains the processed data from the PGO profile.
type Profile struct {

		if err != nil {
			return written, err
		}
	}

	if err := bw.Flush(); err != nil {
		return written, err
	}

	// No need to serialize TotalWeight, it can be trivially recomputed
	// during parsing.

	return written, nil

	if err != nil {
		return nil, fmt.Errorf("error parsing %s: %v", name, err)
	}
	defer of.Close()

	return b.openMachOCommon(name, of, start, limit, offset)
}

func (b *binrep) openELF(name string, start, limit, offset uint64, relocationSymbol string) (plugin.ObjFile, error) {
	ef, err := elfOpen(name)
	if err != nil {
		return nil, fmt.Errorf("error parsing %s: %v", name, err)
	}
	defer ef.Close()

	if len(matches[2]) > 0 {
		minor = atoi(string(matches[2][1:]))
	}
	if len(matches[3]) > 0 {
		patch = atoi(string(matches[3][1:]))
	}
	if parseError != nil {
		t.Logf("error parsing swig version %q, continuing anyway: %s", string(matches[0]), parseError)
		return
	}
	t.Logf("found swig version %d.%d.%d", major, minor, patch)
	if major < 3 || (major == 3 && minor == 0 && patch < 6) {

	// Source files
	sourceFiles []*rawFile
}

type parseError struct {
	ErrorList   *scanner.ErrorList
	ErrorString string
}

// parseErrorToString converts the error from parsing the file into a string
// representation. A nil error is converted to an empty string, and all other
// errors are converted to a JSON-marshaled parseError struct, with ErrorList

	if err != nil {
		return nil, nil, err
	}
	ropt.OutputFormat = c.format
	if len(cmd) == 2 {
		s, err := regexp.Compile(cmd[1])
		if err != nil {
			return nil, nil, fmt.Errorf("parsing argument regexp %s: %v", cmd[1], err)
		}
		ropt.Symbol = s
	}

	rpt := report.New(p, ropt)
	if !relative {
		if err := applyFocus(p, numLabelUnits, cfg, o.UI); err != nil {
			return nil, nil, err
		}

	if err != nil {
		return fmt.Errorf("error opening profile: %w", err)
	}
	defer f.Close()

	r := bufio.NewReader(f)
	d, err := pgo.FromPProf(r)
	if err != nil {
		return fmt.Errorf("error parsing profile: %w", err)
	}

	var out *os.File
	if outputFile == "" {
		out = os.Stdout
	} else {
		out, err = os.Create(outputFile)
		if err != nil {
			return fmt.Errorf("error creating output file: %w", err)

enormous amount of work.

Cgo takes a different approach. It determines the meaning of C
identifiers not by parsing C code but by feeding carefully constructed
programs into the system C compiler and interpreting the generated
error messages, debug information, and object files. In practice,
parsing these is significantly less work and more robust than parsing
C source.

Cgo first invokes gcc -E -dM on the preamble, in order to find out

			if err != nil {
				t.Fatalf("error opening %v: %v", profFile, err)
			}
			defer originalPprofFile.Close()

			p, err := profile.Parse(originalPprofFile)
			if err != nil {
				t.Fatalf("error parsing %v: %v", profFile, err)
			}

			// Move the samples count value-type to the 0 index.
			p.SampleType = []*profile.ValueType{p.SampleType[tc.originalIndex]}

			// Ensure we only have a single set of sample values.