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cmd/gc: run escape analysis in call graph dependency order

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If there are mutually recursive functions, there is a cycle in
the dependency graph, so the order is actually dependency order
among the strongly connected components: mutually recursive
functions get put into the same batch and analyzed together.
(Until now the entire package was put in one batch.)

The non-recursive case (single function, maybe with some
closures inside) will be able to be more precise about inputs
that escape only back to outputs, but that is not implemented yet.

R=ken2
CC=golang-dev, lvd
https://golang.org/cl/6304050
This commit is contained in:
Russ Cox 2012-06-07 03:15:09 -04:00
parent 6363fc5aa6
commit 9fe424737b
1 changed files with 332 additions and 161 deletions
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493
src/cmd/gc/esc.c
View File

@ -1,8 +1,162 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//
// Escape analysis.
#include <u.h>
#include <libc.h>
#include "go.h"
// Run analysis on minimal sets of mutually recursive functions
// or single non-recursive functions, bottom up.
//
// Finding these sets is finding strongly connected components
// in the static call graph. The algorithm for doing that is taken
// from Sedgewick, Algorithms, Second Edition, p. 482, with two
// adaptations.
//
// First, a hidden closure function (n->curfn != N) cannot be the
// root of a connected component. Refusing to use it as a root
// forces it into the component of the function in which it appears.
// The analysis assumes that closures and the functions in which they
// appear are analyzed together, so that the aliasing between their
// variables can be modeled more precisely.
//
// Second, each function becomes two virtual nodes in the graph,
// with numbers n and n+1. We record the function's node number as n
// but search from node n+1. If the search tells us that the component
// number (min) is n+1, we know that this is a trivial component: one function
// plus its closures. If the search tells us that the component number is
// n, then there was a path from node n+1 back to node n, meaning that
// the function set is mutually recursive. The escape analysis can be
// more precise when analyzing a single non-recursive function than
// when analyzing a set of mutually recursive functions.
static NodeList *stack;
static uint32 visitgen;
static uint32 visit(Node*);
static uint32 visitcode(Node*, uint32);
static uint32 visitcodelist(NodeList*, uint32);
static void analyze(NodeList*, int);
enum
{
EscFuncUnknown = 0,
EscFuncPlanned,
EscFuncStarted,
EscFuncTagged,
};
void
escapes(NodeList *all)
{
NodeList *l;
for(l=all; l; l=l->next)
l->n->walkgen = 0;
visitgen = 0;
for(l=all; l; l=l->next)
if(l->n->op == ODCLFUNC && l->n->curfn == N)
visit(l->n);
for(l=all; l; l=l->next)
l->n->walkgen = 0;
}
static uint32
visit(Node *n)
{
uint32 min, recursive;
NodeList *l, *block;
if(n->walkgen > 0) {
// already visited
return n->walkgen;
}
visitgen++;
n->walkgen = visitgen;
visitgen++;
min = visitgen;
l = mal(sizeof *l);
l->next = stack;
l->n = n;
stack = l;
min = visitcodelist(n->nbody, min);
if((min == n->walkgen || min == n->walkgen+1) && n->curfn == N) {
// This node is the root of a strongly connected component.
// The original min passed to visitcodelist was n->walkgen+1.
// If visitcodelist found its way back to n->walkgen, then this
// block is a set of mutually recursive functions.
// Otherwise it's just a lone function that does not recurse.
recursive = min == n->walkgen;
// Remove connected component from stack.
// Mark walkgen so that future visits return a large number
// so as not to affect the caller's min.
block = stack;
for(l=stack; l->n != n; l=l->next)
l->n->walkgen = (uint32)~0U;
n->walkgen = (uint32)~0U;
stack = l->next;
l->next = nil;
// Run escape analysis on this set of functions.
analyze(block, recursive);
}
return min;
}
static uint32
visitcodelist(NodeList *l, uint32 min)
{
for(; l; l=l->next)
min = visitcode(l->n, min);
return min;
}
static uint32
visitcode(Node *n, uint32 min)
{
Node *fn;
uint32 m;
if(n == N)
return min;
min = visitcodelist(n->ninit, min);
min = visitcode(n->left, min);
min = visitcode(n->right, min);
min = visitcodelist(n->list, min);
min = visitcode(n->ntest, min);
min = visitcode(n->nincr, min);
min = visitcodelist(n->nbody, min);
min = visitcodelist(n->nelse, min);
min = visitcodelist(n->rlist, min);
if(n->op == OCALLFUNC || n->op == OCALLMETH) {
fn = n->left;
if(n->op == OCALLMETH)
fn = n->left->right->sym->def;
if(fn && fn->op == ONAME && fn->class == PFUNC && fn->defn && fn->defn->nbody)
if((m = visit(fn->defn)) < min)
min = m;
}
if(n->op == OCLOSURE)
if((m = visit(n->closure)) < min)
min = m;
return min;
}
// An escape analysis pass for a set of functions.
//
// First escfunc, esc and escassign recurse over the ast of each
// function to dig out flow(dst,src) edges between any
@ -22,75 +176,85 @@
// not escape, then new(T) can be rewritten into a stack allocation.
// The same is true of slice literals.
//
// If escape analysis is disabled (-s), this code is not used.
// If optimizations are disabled (-N), this code is not used.
// Instead, the compiler assumes that any value whose address
// is taken without being immediately dereferenced
// needs to be moved to the heap, and new(T) and slice
// literals are always real allocations.
#include <u.h>
#include <libc.h>
#include "go.h"
typedef struct EscState EscState;
static void escfunc(Node *func);
static void esclist(NodeList *l);
static void esc(Node *n);
static void escloopdepthlist(NodeList *l);
static void escloopdepth(Node *n);
static void escassign(Node *dst, Node *src);
static void esccall(Node*);
static void escflows(Node *dst, Node *src);
static void escflood(Node *dst);
static void escwalk(int level, Node *dst, Node *src);
static void esctag(Node *func);
static void escfunc(EscState*, Node *func);
static void esclist(EscState*, NodeList *l);
static void esc(EscState*, Node *n);
static void escloopdepthlist(EscState*, NodeList *l);
static void escloopdepth(EscState*, Node *n);
static void escassign(EscState*, Node *dst, Node *src);
static void esccall(EscState*, Node*);
static void escflows(EscState*, Node *dst, Node *src);
static void escflood(EscState*, Node *dst);
static void escwalk(EscState*, int level, Node *dst, Node *src);
static void esctag(EscState*, Node *func);
// Fake node that all
// - return values and output variables
// - parameters on imported functions not marked 'safe'
// - assignments to global variables
// flow to.
static Node theSink;
struct EscState {
// Fake node that all
// - return values and output variables
// - parameters on imported functions not marked 'safe'
// - assignments to global variables
// flow to.
Node theSink;
NodeList* dsts; // all dst nodes
int loopdepth; // for detecting nested loop scopes
int pdepth; // for debug printing in recursions.
int dstcount, edgecount; // diagnostic
NodeList* noesc; // list of possible non-escaping nodes, for printing
};
static NodeList* dsts; // all dst nodes
static int loopdepth; // for detecting nested loop scopes
static int pdepth; // for debug printing in recursions.
static Strlit* safetag; // gets slapped on safe parameters' field types for export
static int dstcount, edgecount; // diagnostic
static NodeList* noesc; // list of possible non-escaping nodes, for printing
void
escapes(NodeList *all)
static void
analyze(NodeList *all, int recursive)
{
NodeList *l;
EscState es, *e;
USED(recursive);
theSink.op = ONAME;
theSink.orig = &theSink;
theSink.class = PEXTERN;
theSink.sym = lookup(".sink");
theSink.escloopdepth = -1;
memset(&es, 0, sizeof es);
e = &es;
e->theSink.op = ONAME;
e->theSink.orig = &e->theSink;
e->theSink.class = PEXTERN;
e->theSink.sym = lookup(".sink");
e->theSink.escloopdepth = -1;
safetag = strlit("noescape");
noesc = nil;
if(safetag == nil)
safetag = strlit("noescape");
for(l=all; l; l=l->next)
if(l->n->op == ODCLFUNC)
l->n->esc = EscFuncPlanned;
// flow-analyze functions
for(l=all; l; l=l->next)
if(l->n->op == ODCLFUNC)
escfunc(l->n);
escfunc(e, l->n);
// print("escapes: %d dsts, %d edges\n", dstcount, edgecount);
// print("escapes: %d e->dsts, %d edges\n", e->dstcount, e->edgecount);
// visit the updstream of each dst, mark address nodes with
// addrescapes, mark parameters unsafe
for(l = dsts; l; l=l->next)
escflood(l->n);
for(l = e->dsts; l; l=l->next)
escflood(e, l->n);
// for all top level functions, tag the typenodes corresponding to the param nodes
for(l=all; l; l=l->next)
if(l->n->op == ODCLFUNC)
esctag(l->n);
esctag(e, l->n);
if(debug['m']) {
for(l=noesc; l; l=l->next)
for(l=e->noesc; l; l=l->next)
if(l->n->esc == EscNone)
warnl(l->n->lineno, "%S %hN does not escape",
(l->n->curfn && l->n->curfn->nname) ? l->n->curfn->nname->sym : S,
@ -100,14 +264,18 @@ escapes(NodeList *all)
static void
escfunc(Node *func)
escfunc(EscState *e, Node *func)
{
Node *savefn;
NodeList *ll;
int saveld;
saveld = loopdepth;
loopdepth = 1;
if(func->esc != 1)
fatal("repeat escfunc %N", func->nname);
func->esc = EscFuncStarted;
saveld = e->loopdepth;
e->loopdepth = 1;
savefn = curfn;
curfn = func;
@ -117,45 +285,45 @@ escfunc(Node *func)
switch (ll->n->class) {
case PPARAMOUT:
// output parameters flow to the sink
escflows(&theSink, ll->n);
ll->n->escloopdepth = loopdepth;
escflows(e, &e->theSink, ll->n);
ll->n->escloopdepth = e->loopdepth;
break;
case PPARAM:
if(ll->n->type && !haspointers(ll->n->type))
break;
ll->n->esc = EscNone; // prime for escflood later
noesc = list(noesc, ll->n);
ll->n->escloopdepth = loopdepth;
e->noesc = list(e->noesc, ll->n);
ll->n->escloopdepth = e->loopdepth;
break;
}
}
escloopdepthlist(curfn->nbody);
esclist(curfn->nbody);
escloopdepthlist(e, curfn->nbody);
esclist(e, curfn->nbody);
curfn = savefn;
loopdepth = saveld;
e->loopdepth = saveld;
}
// Mark labels that have no backjumps to them as not increasing loopdepth.
// Mark labels that have no backjumps to them as not increasing e->loopdepth.
// Walk hasn't generated (goto|label)->left->sym->label yet, so we'll cheat
// and set it to one of the following two. Then in esc we'll clear it again.
static Label looping;
static Label nonlooping;
static void
escloopdepthlist(NodeList *l)
escloopdepthlist(EscState *e, NodeList *l)
{
for(; l; l=l->next)
escloopdepth(l->n);
escloopdepth(e, l->n);
}
static void
escloopdepth(Node *n)
escloopdepth(EscState *e, Node *n)
{
if(n == N)
return;
escloopdepthlist(n->ninit);
escloopdepthlist(e, n->ninit);
switch(n->op) {
case OLABEL:
@ -177,26 +345,26 @@ escloopdepth(Node *n)
break;
}
escloopdepth(n->left);
escloopdepth(n->right);
escloopdepthlist(n->list);
escloopdepth(n->ntest);
escloopdepth(n->nincr);
escloopdepthlist(n->nbody);
escloopdepthlist(n->nelse);
escloopdepthlist(n->rlist);
escloopdepth(e, n->left);
escloopdepth(e, n->right);
escloopdepthlist(e, n->list);
escloopdepth(e, n->ntest);
escloopdepth(e, n->nincr);
escloopdepthlist(e, n->nbody);
escloopdepthlist(e, n->nelse);
escloopdepthlist(e, n->rlist);
}
static void
esclist(NodeList *l)
esclist(EscState *e, NodeList *l)
{
for(; l; l=l->next)
esc(l->n);
esc(e, l->n);
}
static void
esc(Node *n)
esc(EscState *e, Node *n)
{
int lno;
NodeList *ll, *lr;
@ -208,30 +376,30 @@ esc(Node *n)
lno = setlineno(n);
if(n->op == OFOR || n->op == ORANGE)
loopdepth++;
e->loopdepth++;
esc(n->left);
esc(n->right);
esc(n->ntest);
esc(n->nincr);
esclist(n->ninit);
esclist(n->nbody);
esclist(n->nelse);
esclist(n->list);
esclist(n->rlist);
esc(e, n->left);
esc(e, n->right);
esc(e, n->ntest);
esc(e, n->nincr);
esclist(e, n->ninit);
esclist(e, n->nbody);
esclist(e, n->nelse);
esclist(e, n->list);
esclist(e, n->rlist);
if(n->op == OFOR || n->op == ORANGE)
loopdepth--;
e->loopdepth--;
if(debug['m'] > 1)
print("%L:[%d] %S esc: %N\n", lineno, loopdepth,
print("%L:[%d] %S esc: %N\n", lineno, e->loopdepth,
(curfn && curfn->nname) ? curfn->nname->sym : S, n);
switch(n->op) {
case ODCL:
// Record loop depth at declaration.
if(n->left)
n->left->escloopdepth = loopdepth;
n->left->escloopdepth = e->loopdepth;
break;
case OLABEL:
@ -241,7 +409,7 @@ esc(Node *n)
} else if(n->left->sym->label == &looping) {
if(debug['m'] > 1)
print("%L: %N looping label\n", lineno, n);
loopdepth++;
e->loopdepth++;
}
// See case OLABEL in escloopdepth above
// else if(n->left->sym->label == nil)
@ -252,7 +420,7 @@ esc(Node *n)
case ORANGE:
// Everything but fixed array is a dereference.
if(isfixedarray(n->type) && n->list->next)
escassign(n->list->next->n, n->right);
escassign(e, n->list->next->n, n->right);
break;
case OSWITCH:
@ -260,111 +428,111 @@ esc(Node *n)
for(ll=n->list; ll; ll=ll->next) { // cases
// ntest->right is the argument of the .(type),
// ll->n->nname is the variable per case
escassign(ll->n->nname, n->ntest->right);
escassign(e, ll->n->nname, n->ntest->right);
}
}
break;
case OAS:
case OASOP:
escassign(n->left, n->right);
escassign(e, n->left, n->right);
break;
case OAS2: // x,y = a,b
if(count(n->list) == count(n->rlist))
for(ll=n->list, lr=n->rlist; ll; ll=ll->next, lr=lr->next)
escassign(ll->n, lr->n);
escassign(e, ll->n, lr->n);
break;
case OAS2RECV: // v, ok = <-ch
case OAS2MAPR: // v, ok = m[k]
case OAS2DOTTYPE: // v, ok = x.(type)
escassign(n->list->n, n->rlist->n);
escassign(e, n->list->n, n->rlist->n);
break;
case OSEND: // ch <- x
escassign(&theSink, n->right);
escassign(e, &e->theSink, n->right);
break;
case ODEFER:
if(loopdepth == 1) // top level
if(e->loopdepth == 1) // top level
break;
// arguments leak out of scope
// TODO: leak to a dummy node instead
// fallthrough
case OPROC:
// go f(x) - f and x escape
escassign(&theSink, n->left->left);
escassign(&theSink, n->left->right); // ODDDARG for call
escassign(e, &e->theSink, n->left->left);
escassign(e, &e->theSink, n->left->right); // ODDDARG for call
for(ll=n->left->list; ll; ll=ll->next)
escassign(&theSink, ll->n);
escassign(e, &e->theSink, ll->n);
break;
case ORETURN:
for(ll=n->list; ll; ll=ll->next)
escassign(&theSink, ll->n);
escassign(e, &e->theSink, ll->n);
break;
case OPANIC:
// Argument could leak through recover.
escassign(&theSink, n->left);
escassign(e, &e->theSink, n->left);
break;
case OAPPEND:
if(!n->isddd)
for(ll=n->list->next; ll; ll=ll->next)
escassign(&theSink, ll->n); // lose track of assign to dereference
escassign(e, &e->theSink, ll->n); // lose track of assign to dereference
break;
case OCALLMETH:
case OCALLFUNC:
case OCALLINTER:
esccall(n);
esccall(e, n);
break;
case OCONV:
case OCONVNOP:
case OCONVIFACE:
escassign(n, n->left);
escassign(e, n, n->left);
break;
case OARRAYLIT:
if(isslice(n->type)) {
n->esc = EscNone; // until proven otherwise
noesc = list(noesc, n);
n->escloopdepth = loopdepth;
e->noesc = list(e->noesc, n);
n->escloopdepth = e->loopdepth;
// Values make it to memory, lose track.
for(ll=n->list; ll; ll=ll->next)
escassign(&theSink, ll->n->right);
escassign(e, &e->theSink, ll->n->right);
} else {
// Link values to array.
for(ll=n->list; ll; ll=ll->next)
escassign(n, ll->n->right);
escassign(e, n, ll->n->right);
}
break;
case OSTRUCTLIT:
// Link values to struct.
for(ll=n->list; ll; ll=ll->next)
escassign(n, ll->n->right);
escassign(e, n, ll->n->right);
break;
case OPTRLIT:
n->esc = EscNone; // until proven otherwise
noesc = list(noesc, n);
n->escloopdepth = loopdepth;
e->noesc = list(e->noesc, n);
n->escloopdepth = e->loopdepth;
// Contents make it to memory, lose track.
escassign(&theSink, n->left);
escassign(e, &e->theSink, n->left);
break;
case OMAPLIT:
n->esc = EscNone; // until proven otherwise
noesc = list(noesc, n);
n->escloopdepth = loopdepth;
e->noesc = list(e->noesc, n);
n->escloopdepth = e->loopdepth;
// Keys and values make it to memory, lose track.
for(ll=n->list; ll; ll=ll->next) {
escassign(&theSink, ll->n->left);
escassign(&theSink, ll->n->right);
escassign(e, &e->theSink, ll->n->left);
escassign(e, &e->theSink, ll->n->right);
}
break;
@ -376,7 +544,7 @@ esc(Node *n)
a = nod(OADDR, ll->n->closure, N);
a->lineno = ll->n->lineno;
typecheck(&a, Erv);
escassign(n, a);
escassign(e, n, a);
}
// fallthrough
case OADDR:
@ -384,9 +552,9 @@ esc(Node *n)
case OMAKEMAP:
case OMAKESLICE:
case ONEW:
n->escloopdepth = loopdepth;
n->escloopdepth = e->loopdepth;
n->esc = EscNone; // until proven otherwise
noesc = list(noesc, n);
e->noesc = list(e->noesc, n);
break;
}
@ -398,7 +566,7 @@ esc(Node *n)
// evaluated in curfn. For expr==nil, dst must still be examined for
// evaluations inside it (e.g *f(x) = y)
static void
escassign(Node *dst, Node *src)
escassign(EscState *e, Node *dst, Node *src)
{
int lno;
@ -406,13 +574,13 @@ escassign(Node *dst, Node *src)
return;
if(debug['m'] > 1)
print("%L:[%d] %S escassign: %hN(%hJ) = %hN(%hJ)\n", lineno, loopdepth,
print("%L:[%d] %S escassign: %hN(%hJ) = %hN(%hJ)\n", lineno, e->loopdepth,
(curfn && curfn->nname) ? curfn->nname->sym : S, dst, dst, src, src);
setlineno(dst);
// Analyze lhs of assignment.
// Replace dst with theSink if we can't track it.
// Replace dst with e->theSink if we can't track it.
switch(dst->op) {
default:
dump("dst", dst);
@ -429,31 +597,31 @@ escassign(Node *dst, Node *src)
case ONAME:
if(dst->class == PEXTERN)
dst = &theSink;
dst = &e->theSink;
break;
case ODOT: // treat "dst.x = src" as "dst = src"
escassign(dst->left, src);
escassign(e, dst->left, src);
return;
case OINDEX:
if(isfixedarray(dst->left->type)) {
escassign(dst->left, src);
escassign(e, dst->left, src);
return;
}
dst = &theSink; // lose track of dereference
dst = &e->theSink; // lose track of dereference
break;
case OIND:
case ODOTPTR:
dst = &theSink; // lose track of dereference
dst = &e->theSink; // lose track of dereference
break;
case OINDEXMAP:
// lose track of key and value
escassign(&theSink, dst->right);
dst = &theSink;
escassign(e, &e->theSink, dst->right);
dst = &e->theSink;
break;
}
lno = setlineno(src);
pdepth++;
e->pdepth++;
switch(src->op) {
case OADDR: // dst = &x
@ -471,7 +639,7 @@ escassign(Node *dst, Node *src)
case OMAKESLICE:
case ONEW:
case OCLOSURE:
escflows(dst, src);
escflows(e, dst, src);
break;
case ODOT:
@ -489,18 +657,18 @@ escassign(Node *dst, Node *src)
case OSLICE:
case OSLICEARR:
// Conversions, field access, slice all preserve the input value.
escassign(dst, src->left);
escassign(e, dst, src->left);
break;
case OAPPEND:
// Append returns first argument.
escassign(dst, src->list->n);
escassign(e, dst, src->list->n);
break;
case OINDEX:
// Index of array preserves input value.
if(isfixedarray(src->left->type))
escassign(dst, src->left);
escassign(e, dst, src->left);
break;
case OADD:
@ -520,13 +688,12 @@ escassign(Node *dst, Node *src)
// Might be pointer arithmetic, in which case
// the operands flow into the result.
// TODO(rsc): Decide what the story is here. This is unsettling.
escassign(dst, src->left);
escassign(dst, src->right);
escassign(e, dst, src->left);
escassign(e, dst, src->right);
break;
}
pdepth--;
e->pdepth--;
lineno = lno;
}
@ -538,7 +705,7 @@ escassign(Node *dst, Node *src)
// different for methods vs plain functions and for imported vs
// this-package
static void
esccall(Node *n)
esccall(EscState *e, Node *n)
{
NodeList *ll, *lr;
Node *a, *fn, *src;
@ -578,66 +745,68 @@ esccall(Node *n)
}
}
if(fn && fn->op == ONAME && fn->class == PFUNC && fn->defn && fn->defn->nbody && fn->ntype) {
// Local function. Incorporate into flow graph.
if(fn && fn->op == ONAME && fn->class == PFUNC && fn->defn && fn->defn->nbody && fn->ntype && fn->defn->esc < EscFuncTagged) {
// Local function in this round. Incorporate into flow graph.
if(fn->defn->esc == EscFuncUnknown)
fatal("graph inconsistency");
// Receiver.
if(n->op != OCALLFUNC)
escassign(fn->ntype->left->left, n->left->left);
escassign(e, fn->ntype->left->left, n->left->left);
for(lr=fn->ntype->list; ll && lr; ll=ll->next, lr=lr->next) {
src = ll->n;
if(lr->n->isddd && !n->isddd) {
// Introduce ODDDARG node to represent ... allocation.
src = nod(ODDDARG, N, N);
src->escloopdepth = loopdepth;
src->escloopdepth = e->loopdepth;
src->lineno = n->lineno;
src->esc = EscNone; // until we find otherwise
noesc = list(noesc, src);
e->noesc = list(e->noesc, src);
n->right = src;
}
if(lr->n->left != N)
escassign(lr->n->left, src);
escassign(e, lr->n->left, src);
if(src != ll->n)
break;
}
// "..." arguments are untracked
for(; ll; ll=ll->next)
escassign(&theSink, ll->n);
escassign(e, &e->theSink, ll->n);
return;
}
// Imported function. Use the escape tags.
// Imported or completely analyzed function. Use the escape tags.
if(n->op != OCALLFUNC) {
t = getthisx(fntype)->type;
if(!t->note || strcmp(t->note->s, safetag->s) != 0)
escassign(&theSink, n->left->left);
escassign(e, &e->theSink, n->left->left);
}
for(t=getinargx(fntype)->type; ll; ll=ll->next) {
src = ll->n;
if(t->isddd && !n->isddd) {
// Introduce ODDDARG node to represent ... allocation.
src = nod(ODDDARG, N, N);
src->escloopdepth = loopdepth;
src->escloopdepth = e->loopdepth;
src->lineno = n->lineno;
src->esc = EscNone; // until we find otherwise
noesc = list(noesc, src);
e->noesc = list(e->noesc, src);
n->right = src;
}
if(!t->note || strcmp(t->note->s, safetag->s) != 0)
escassign(&theSink, src);
escassign(e, &e->theSink, src);
if(src != ll->n)
break;
t = t->down;
}
// "..." arguments are untracked
for(; ll; ll=ll->next)
escassign(&theSink, ll->n);
escassign(e, &e->theSink, ll->n);
}
// Store the link src->dst in dst, throwing out some quick wins.
static void
escflows(Node *dst, Node *src)
escflows(EscState *e, Node *dst, Node *src)
{
if(dst == nil || src == nil || dst == src)
return;
@ -650,10 +819,10 @@ escflows(Node *dst, Node *src)
print("%L::flows:: %hN <- %hN\n", lineno, dst, src);
if(dst->escflowsrc == nil) {
dsts = list(dsts, dst);
dstcount++;
e->dsts = list(e->dsts, dst);
e->dstcount++;
}
edgecount++;
e->edgecount++;
dst->escflowsrc = list(dst->escflowsrc, src);
}
@ -664,11 +833,11 @@ escflows(Node *dst, Node *src)
// so this address doesn't leak (yet).
// If level == 0, it means the /value/ of this node can reach the root of this flood.
// so if this node is an OADDR, it's argument should be marked as escaping iff
// it's currfn/loopdepth are different from the flood's root.
// it's currfn/e->loopdepth are different from the flood's root.
// Once an object has been moved to the heap, all of it's upstream should be considered
// escaping to the global scope.
static void
escflood(Node *dst)
escflood(EscState *e, Node *dst)
{
NodeList *l;
@ -687,12 +856,12 @@ escflood(Node *dst)
for(l = dst->escflowsrc; l; l=l->next) {
walkgen++;
escwalk(0, dst, l->n);
escwalk(e, 0, dst, l->n);
}
}
static void
escwalk(int level, Node *dst, Node *src)
escwalk(EscState *e, int level, Node *dst, Node *src)
{
NodeList *ll;
int leaks;
@ -703,10 +872,10 @@ escwalk(int level, Node *dst, Node *src)
if(debug['m']>1)
print("escwalk: level:%d depth:%d %.*s %hN(%hJ) scope:%S[%d]\n",
level, pdepth, pdepth, "\t\t\t\t\t\t\t\t\t\t", src, src,
level, e->pdepth, e->pdepth, "\t\t\t\t\t\t\t\t\t\t", src, src,
(src->curfn && src->curfn->nname) ? src->curfn->nname->sym : S, src->escloopdepth);
pdepth++;
e->pdepth++;
leaks = (level <= 0) && (dst->escloopdepth < src->escloopdepth);
@ -723,7 +892,7 @@ escwalk(int level, Node *dst, Node *src)
if(src->class == PPARAMREF) {
if(leaks && debug['m'])
warnl(src->lineno, "leaking closure reference %hN", src);
escwalk(level, dst, src->closure);
escwalk(e, level, dst, src->closure);
}
break;
@ -735,7 +904,7 @@ escwalk(int level, Node *dst, Node *src)
if(debug['m'])
warnl(src->lineno, "%hN escapes to heap", src);
}
escwalk(level-1, dst, src->left);
escwalk(e, level-1, dst, src->left);
break;
case OARRAYLIT:
@ -764,21 +933,23 @@ escwalk(int level, Node *dst, Node *src)
case ODOTPTR:
case OINDEXMAP:
case OIND:
escwalk(level+1, dst, src->left);
escwalk(e, level+1, dst, src->left);
}
for(ll=src->escflowsrc; ll; ll=ll->next)
escwalk(level, dst, ll->n);
escwalk(e, level, dst, ll->n);
pdepth--;
e->pdepth--;
}
static void
esctag(Node *func)
esctag(EscState *e, Node *func)
{
Node *savefn;
NodeList *ll;
func->esc = EscFuncTagged;
// External functions must be assumed unsafe.
if(func->nbody == nil)
return;