From cb8a4872d57c90a2bff593c565212c80b181f2da Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Sun, 10 May 2015 17:35:52 -0400
Subject: [PATCH] Added a rudimentary profiler to the Windows backend.

---
 windows/GNUmakeinc.mk |   6 ++
 windows/profiler.c    |  35 +++++++++++
 windows/profiler.go   | 131 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 172 insertions(+)
 create mode 100644 windows/profiler.c
 create mode 100644 windows/profiler.go

diff --git a/windows/GNUmakeinc.mk b/windows/GNUmakeinc.mk
index 538c3ae2..fe40521c 100644
--- a/windows/GNUmakeinc.mk
+++ b/windows/GNUmakeinc.mk
@@ -44,3 +44,9 @@ else
 	RC = i686-w64-mingw32-windres
 	archmflag = -m32
 endif
+
+ifeq ($(PROFILE),1)
+	osCFILES += windows/profiler.c
+	osCFLAGS += -finstrument-functions
+	osLDFLAGS += -finstrument-functions
+endif
diff --git a/windows/profiler.c b/windows/profiler.c
new file mode 100644
index 00000000..9573de20
--- /dev/null
+++ b/windows/profiler.c
@@ -0,0 +1,35 @@
+// 10 may 2015
+#include "uipriv_windows.h"
+
+static FILE *fprof = NULL;
+
+__attribute__((no_instrument_function)) static void init(void)
+{
+	if (fprof != NULL)
+		return;
+	fprof = fopen("profiler.out", "w");
+	if (fprof == NULL) {
+		fprintf(stderr, "error opening profiler output file\n");
+		abort();
+	}
+}
+
+__attribute__((no_instrument_function)) void __cyg_profile_func_enter(void *this_fn, void *call_site)
+{
+	LARGE_INTEGER counter;
+
+	init();
+	QueryPerformanceCounter(&counter);
+	fprintf(fprof, "enter %p %I64d\n", this_fn, counter.QuadPart);
+	fflush(fprof);
+}
+
+__attribute__((no_instrument_function)) void __cyg_profile_func_exit(void *this_fn, void *call_site)
+{
+	LARGE_INTEGER counter;
+
+	init();
+	QueryPerformanceCounter(&counter);
+	fprintf(fprof, "leave %p %I64d\n", this_fn, counter.QuadPart);
+	fflush(fprof);
+}
diff --git a/windows/profiler.go b/windows/profiler.go
new file mode 100644
index 00000000..9dc074eb
--- /dev/null
+++ b/windows/profiler.go
@@ -0,0 +1,131 @@
+// 10 may 2015
+package main
+
+import (
+	"fmt"
+	"os"
+	"bufio"
+	"debug/pe"
+	"strings"
+	"strconv"
+)
+
+func getsymbols(filename string) map[uint64]string {
+	dll, err := pe.Open(os.Args[1])
+	if err != nil {
+		panic(err)
+	}
+	defer dll.Close()
+
+	imagebase := uint64(0)
+	switch o := dll.OptionalHeader.(type) {
+	case *pe.OptionalHeader32:
+		imagebase = uint64(o.ImageBase)
+	case *pe.OptionalHeader64:
+		imagebase = o.ImageBase
+	default:
+		panic("unknown image base; can't continue")
+	}
+
+	names := make(map[uint64]string)
+	for _, s := range dll.Symbols {
+		switch s.SectionNumber {
+		case 0, -1, -2:		// undefined, constant, debugging
+			continue
+		}
+		addr := uint64(s.Value)
+		addr += imagebase
+		section := dll.Sections[s.SectionNumber - 1]
+		addr += uint64(section.VirtualAddress)
+		names[addr] = s.Name
+	}
+
+	return names
+}
+
+type Entry struct {
+	Leave	bool
+	Func		string
+	PerfCtr	uint64
+}
+
+func getentries(filename string, names map[uint64]string) []Entry {
+	f, err := os.Open(os.Args[2])
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	entries := make([]Entry, 0, 10240)
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		l := scanner.Text()
+		l = strings.TrimSpace(l)
+		parts := strings.Split(l, " ")
+		addr, err := strconv.ParseUint(parts[1], 16, 64)
+		if err != nil {
+			panic(err)
+		}
+		e := Entry{}
+		e.Leave = parts[0] == "leave"
+		e.Func = names[addr]
+		e.PerfCtr, err = strconv.ParseUint(parts[2], 10, 64)
+		if err != nil {
+			panic(err)
+		}
+		entries = append(entries, e)
+	}
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+
+	return entries
+}
+
+type Profile struct {
+	Calls			uint
+	TotalTime		uint64
+	PerfCtr		[]uint64
+}
+
+var profile map[string]*Profile
+
+func run(e Entry) {
+	p := profile[e.Func]
+	if p == nil {
+		p = new(Profile)
+	}
+	if !e.Leave {
+		p.Calls++
+		p.PerfCtr = append(p.PerfCtr, e.PerfCtr)
+	} else {
+		start := p.PerfCtr[len(p.PerfCtr) - 1]
+		p.PerfCtr = p.PerfCtr[:len(p.PerfCtr) - 1]
+		p.TotalTime += (e.PerfCtr - start)
+	}
+	profile[e.Func] = p
+}
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Fprintf(os.Stderr, "usage: %s dll profout\n", os.Args[0])
+		os.Exit(1)
+	}
+
+	names := getsymbols(os.Args[1])
+	entries := getentries(os.Args[2], names)
+	profile = make(map[string]*Profile)
+	for _, e := range entries {
+		run(e)
+	}
+	for f, p := range profile {
+		fmt.Printf("%s %v %v ", f, p.Calls, p.TotalTime)
+		if p.Calls != 0 {
+			fmt.Printf("%v", float64(p.TotalTime) / float64(p.Calls))
+		} else {
+			fmt.Printf("%v", float64(0))
+		}
+		fmt.Printf("\n")
+	}
+}