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[mono][interp] Fixes for compilation of huge methods (#57346)
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* [interp] Disable inlining if interpreter var limit is excedeed

Currently, the interpreter has a 64k limit for the stack space to be used by vars. If we reach this limit, retry compilation with inlining disabled, since inlining can increase significantly the method code.

* [interp] Improve cprop speed by removing redundant memclear

Instead of clearing the defs for all vars, clear only for the vars used within a basic block, as the jit does. Otherwise, for large methods with many locals and many bblocks, we end up spending most of the time clearing memory. Improves speed of cprop by 20-30%, while for huge methods it can improve it by orders of magnitude.
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@BrzVlad
BrzVlad authored Aug 13, 2021
1 parent 8327778 commit 60d9b98
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Showing 2 changed files with 80 additions and 39 deletions.
116 changes: 77 additions & 39 deletions src/mono/mono/mini/interp/transform.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2779,6 +2779,9 @@ interp_method_check_inlining (TransformData *td, MonoMethod *method, MonoMethodS
{
MonoMethodHeaderSummary header;

if (td->disable_inlining)
return FALSE;

if (method->flags & METHOD_ATTRIBUTE_REQSECOBJ)
/* Used to mark methods containing StackCrawlMark locals */
return FALSE;
Expand Down Expand Up @@ -8292,6 +8295,42 @@ cprop_sreg (TransformData *td, InterpInst *ins, int *psreg, LocalValue *local_de
}
}

static void
foreach_local_var (TransformData *td, InterpInst *ins, gpointer data, void (*callback)(TransformData*, int, gpointer))
{
int opcode = ins->opcode;
if (mono_interp_op_sregs [opcode]) {
for (int i = 0; i < mono_interp_op_sregs [opcode]; i++) {
int sreg = ins->sregs [i];

if (sreg == MINT_CALL_ARGS_SREG) {
int *call_args = ins->info.call_args;
if (call_args) {
int var = *call_args;
while (var != -1) {
callback (td, var, data);
call_args++;
var = *call_args;
}
}
} else {
callback (td, sreg, data);
}
}
}

if (mono_interp_op_dregs [opcode])
callback (td, ins->dreg, data);
}

static void
clear_local_defs (TransformData *td, int var, void *data)
{
LocalValue *local_defs = (LocalValue*) data;
local_defs [var].type = LOCAL_VALUE_NONE;
local_defs [var].ins = NULL;
}

static void
interp_cprop (TransformData *td)
{
Expand All @@ -8316,8 +8355,8 @@ interp_cprop (TransformData *td)
// Set cbb since we do some instruction inserting below
td->cbb = bb;

// FIXME This is excessive. Remove this once we have SSA
memset (local_defs, 0, td->locals_size * sizeof (LocalValue));
for (ins = bb->first_ins; ins != NULL; ins = ins->next)
foreach_local_var (td, ins, local_defs, clear_local_defs);

if (td->verbose_level)
g_print ("BB%d\n", bb->index);
Expand Down Expand Up @@ -8947,34 +8986,6 @@ interp_optimize_code (TransformData *td)
MONO_TIME_TRACK (mono_interp_stats.super_instructions_time, interp_super_instructions (td));
}

static void
foreach_local_var (TransformData *td, InterpInst *ins, int data, void (*callback)(TransformData*, int, int))
{
int opcode = ins->opcode;
if (mono_interp_op_sregs [opcode]) {
for (int i = 0; i < mono_interp_op_sregs [opcode]; i++) {
int sreg = ins->sregs [i];

if (sreg == MINT_CALL_ARGS_SREG) {
int *call_args = ins->info.call_args;
if (call_args) {
int var = *call_args;
while (var != -1) {
callback (td, var, data);
call_args++;
var = *call_args;
}
}
} else {
callback (td, sreg, data);
}
}
}

if (mono_interp_op_dregs [opcode])
callback (td, ins->dreg, data);
}

static void
set_var_live_range (TransformData *td, int var, int ins_index)
{
Expand All @@ -8986,6 +8997,12 @@ set_var_live_range (TransformData *td, int var, int ins_index)
td->locals [var].live_end = ins_index;
}

static void
set_var_live_range_cb (TransformData *td, int var, gpointer data)
{
set_var_live_range (td, var, (int)(gsize)data);
}

static void
initialize_global_var (TransformData *td, int var, int bb_index)
{
Expand All @@ -9002,6 +9019,12 @@ initialize_global_var (TransformData *td, int var, int bb_index)
alloc_global_var_offset (td, var);
td->locals [var].flags |= INTERP_LOCAL_FLAG_GLOBAL;
}
}

static void
initialize_global_var_cb (TransformData *td, int var, gpointer data)
{
initialize_global_var (td, var, (int)(gsize)data);
}

static void
Expand All @@ -9026,7 +9049,7 @@ initialize_global_vars (TransformData *td)
td->locals [var].flags |= INTERP_LOCAL_FLAG_GLOBAL;
}
}
foreach_local_var (td, ins, bb->index, initialize_global_var);
foreach_local_var (td, ins, (gpointer)(gsize)bb->index, initialize_global_var_cb);
}
}
}
Expand Down Expand Up @@ -9296,7 +9319,7 @@ interp_alloc_offsets (TransformData *td)
// The arg of the call is no longer global
*call_args = new_var;
// Also update liveness for this instruction
foreach_local_var (td, new_inst, ins_index, set_var_live_range);
foreach_local_var (td, new_inst, (gpointer)(gsize)ins_index, set_var_live_range_cb);
ins_index++;
}
} else {
Expand Down Expand Up @@ -9334,7 +9357,7 @@ interp_alloc_offsets (TransformData *td)
}
}
// Set live_start and live_end for every referenced local that is not global
foreach_local_var (td, ins, ins_index, set_var_live_range);
foreach_local_var (td, ins, (gpointer)(gsize)ins_index, set_var_live_range_cb);
ins_index++;
}
gint32 current_offset = td->total_locals_size;
Expand Down Expand Up @@ -9448,6 +9471,7 @@ generate (MonoMethod *method, MonoMethodHeader *header, InterpMethod *rtm, MonoG
int i;
TransformData transform_data;
TransformData *td;
gboolean retry_compilation = FALSE;
static gboolean verbose_method_inited;
static char* verbose_method_name;

Expand All @@ -9456,6 +9480,7 @@ generate (MonoMethod *method, MonoMethodHeader *header, InterpMethod *rtm, MonoG
verbose_method_inited = TRUE;
}

retry:
memset (&transform_data, 0, sizeof(transform_data));
td = &transform_data;

Expand All @@ -9480,6 +9505,8 @@ generate (MonoMethod *method, MonoMethodHeader *header, InterpMethod *rtm, MonoG
td->seq_points = g_ptr_array_new ();
td->verbose_level = mono_interp_traceopt;
td->prof_coverage = mono_profiler_coverage_instrumentation_enabled (method);
if (retry_compilation)
td->disable_inlining = TRUE;
rtm->data_items = td->data_items;

if (td->prof_coverage)
Expand Down Expand Up @@ -9527,12 +9554,21 @@ generate (MonoMethod *method, MonoMethodHeader *header, InterpMethod *rtm, MonoG
generate_compacted_code (td);

if (td->total_locals_size >= G_MAXUINT16) {
char *name = mono_method_get_full_name (method);
char *msg = g_strdup_printf ("Unable to run method '%s': locals size too big.", name);
g_free (name);
mono_error_set_generic_error (error, "System", "InvalidProgramException", "%s", msg);
g_free (msg);
goto exit;
if (td->disable_inlining) {
char *name = mono_method_get_full_name (method);
char *msg = g_strdup_printf ("Unable to run method '%s': locals size too big.", name);
g_free (name);
mono_error_set_generic_error (error, "System", "InvalidProgramException", "%s", msg);
g_free (msg);
retry_compilation = FALSE;
goto exit;
} else {
// We give the method another chance to compile with inlining disabled
retry_compilation = TRUE;
goto exit;
}
} else {
retry_compilation = FALSE;
}

if (td->verbose_level) {
Expand Down Expand Up @@ -9623,6 +9659,8 @@ generate (MonoMethod *method, MonoMethodHeader *header, InterpMethod *rtm, MonoG
if (td->line_numbers)
g_array_free (td->line_numbers, TRUE);
mono_mempool_destroy (td->mempool);
if (retry_compilation)
goto retry;
}

gboolean
Expand Down
3 changes: 3 additions & 0 deletions src/mono/mono/mini/interp/transform.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -208,6 +208,9 @@ typedef struct
GList *dont_inline;
int inline_depth;
int has_localloc : 1;
// If method compilation fails due to certain limits being exceeded, we disable inlining
// and retry compilation.
int disable_inlining : 1;
// If the current method (inlined_method) has the aggressive inlining attribute, we no longer
// bail out of inlining when having to generate certain opcodes (like call, throw).
int aggressive_inlining : 1;
Expand Down

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