tools/syz-trace2syz/proggen: add ParseFile function

Current code structuring has 2 problems:

1. parsing anything with proggen requires complex multistep dance including
 - parsing data with parser
 - walking the resulting tree manually and calling proggen on each
 - then for each context
   - calling FillOutMemory (unclear why it's not part of parsing)
   - calling prog.Finalize
   - checking is the program is not too large
All of this duplicated across trace2syz and tests.
And any new tests or fuzzers we will write will need to duplicate
all of this logic too.

2. As the result of this structuring, lots of proggen guts
and implementation details are exposed.
While none of the callers are actually intersted in Context details,
they are not interested in Context itself whatsoever.

What every caller wants is "here is data to parse, give me programs".
Add such function.

1 files changed, 0 insertions, 10 deletions

diff --git a/tools/syz-trace2syz/parser/parser.go b/tools/syz-trace2syz/parser/parser.go
index 6076b9a18..08be7f254 100644
--- a/tools/syz-trace2syz/parser/parser.go
+++ b/tools/syz-trace2syz/parser/parser.go
@@ -6,7 +6,6 @@ package parser
 import (
 	"bufio"
 	"bytes"
-	"io/ioutil"
 	"strings"
 
 	"github.com/google/syzkaller/pkg/log"
@@ -48,12 +47,3 @@ func ParseLoop(data []byte) *TraceTree {
 	}
 	return tree
 }
-
-// Parse parses a trace of system calls and returns an intermediate representation
-func Parse(filename string) *TraceTree {
-	data, err := ioutil.ReadFile(filename)
-	if err != nil {
-		log.Fatalf("error reading file: %s", err.Error())
-	}
-	return ParseLoop(data)
-}