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authorJason Ekstrand <[email protected]>2019-01-09 14:56:02 -0600
committerJason Ekstrand <[email protected]>2019-03-25 14:40:54 -0500
commit39da1deb497af55496308c0867b5ce5a0e9df56e (patch)
treef6d0f1ebfd9b50659e155f84499c7535c97e9bed /src
parent551950cacda9cf86e43b57beb0116fdf580cad1e (diff)
nir/lower_io: Add a bounds-checked 64-bit global address format
Reviewed-by: Lionel Landwerlin <[email protected]>
Diffstat (limited to 'src')
-rw-r--r--src/compiler/nir/nir.h10
-rw-r--r--src/compiler/nir/nir_lower_io.c89
2 files changed, 93 insertions, 6 deletions
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 92b17275b45..1033b545d6a 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3038,6 +3038,16 @@ typedef enum {
nir_address_format_64bit_global,
/**
+ * An address format which is a bounds-checked 64-bit global GPU address.
+ *
+ * The address is comprised as a 32-bit vec4 where .xy are a uint64_t base
+ * address stored with the low bits in .x and high bits in .y, .z is a
+ * size, and .w is an offset. When the final I/O operation is lowered, .w
+ * is checked against .z and the operation is predicated on the result.
+ */
+ nir_address_format_64bit_bounded_global,
+
+ /**
* An address format which is comprised of a vec2 where the first
* component is a buffer index and the second is an offset.
*/
diff --git a/src/compiler/nir/nir_lower_io.c b/src/compiler/nir/nir_lower_io.c
index 749ac91d47e..d39567ff1d1 100644
--- a/src/compiler/nir/nir_lower_io.c
+++ b/src/compiler/nir/nir_lower_io.c
@@ -599,6 +599,13 @@ build_addr_iadd(nir_builder *b, nir_ssa_def *addr,
assert(addr->num_components == 1);
return nir_iadd(b, addr, offset);
+ case nir_address_format_64bit_bounded_global:
+ assert(addr->num_components == 4);
+ return nir_vec4(b, nir_channel(b, addr, 0),
+ nir_channel(b, addr, 1),
+ nir_channel(b, addr, 2),
+ nir_iadd(b, nir_channel(b, addr, 3), offset));
+
case nir_address_format_32bit_index_offset:
assert(addr->num_components == 2);
return nir_vec2(b, nir_channel(b, addr, 0),
@@ -638,7 +645,8 @@ static bool
addr_format_is_global(nir_address_format addr_format)
{
return addr_format == nir_address_format_32bit_global ||
- addr_format == nir_address_format_64bit_global;
+ addr_format == nir_address_format_64bit_global ||
+ addr_format == nir_address_format_64bit_bounded_global;
}
static nir_ssa_def *
@@ -651,6 +659,11 @@ addr_to_global(nir_builder *b, nir_ssa_def *addr,
assert(addr->num_components == 1);
return addr;
+ case nir_address_format_64bit_bounded_global:
+ assert(addr->num_components == 4);
+ return nir_iadd(b, nir_pack_64_2x32(b, nir_channels(b, addr, 0x3)),
+ nir_u2u64(b, nir_channel(b, addr, 3)));
+
case nir_address_format_32bit_index_offset:
unreachable("Cannot get a 64-bit address with this address format");
}
@@ -658,6 +671,22 @@ addr_to_global(nir_builder *b, nir_ssa_def *addr,
unreachable("Invalid address format");
}
+static bool
+addr_format_needs_bounds_check(nir_address_format addr_format)
+{
+ return addr_format == nir_address_format_64bit_bounded_global;
+}
+
+static nir_ssa_def *
+addr_is_in_bounds(nir_builder *b, nir_ssa_def *addr,
+ nir_address_format addr_format, unsigned size)
+{
+ assert(addr_format == nir_address_format_64bit_bounded_global);
+ assert(addr->num_components == 4);
+ return nir_ige(b, nir_channel(b, addr, 2),
+ nir_iadd_imm(b, nir_channel(b, addr, 3), size));
+}
+
static nir_ssa_def *
build_explicit_io_load(nir_builder *b, nir_intrinsic_instr *intrin,
nir_ssa_def *addr, nir_address_format addr_format,
@@ -709,9 +738,32 @@ build_explicit_io_load(nir_builder *b, nir_intrinsic_instr *intrin,
load->num_components = num_components;
nir_ssa_dest_init(&load->instr, &load->dest, num_components,
intrin->dest.ssa.bit_size, intrin->dest.ssa.name);
- nir_builder_instr_insert(b, &load->instr);
- return &load->dest.ssa;
+ assert(load->dest.ssa.bit_size % 8 == 0);
+
+ if (addr_format_needs_bounds_check(addr_format)) {
+ /* The Vulkan spec for robustBufferAccess gives us quite a few options
+ * as to what we can do with an OOB read. Unfortunately, returning
+ * undefined values isn't one of them so we return an actual zero.
+ */
+ nir_const_value zero_val;
+ memset(&zero_val, 0, sizeof(zero_val));
+ nir_ssa_def *zero = nir_build_imm(b, load->num_components,
+ load->dest.ssa.bit_size, zero_val);
+
+ const unsigned load_size =
+ (load->dest.ssa.bit_size / 8) * load->num_components;
+ nir_push_if(b, addr_is_in_bounds(b, addr, addr_format, load_size));
+
+ nir_builder_instr_insert(b, &load->instr);
+
+ nir_pop_if(b, NULL);
+
+ return nir_if_phi(b, &load->dest.ssa, zero);
+ } else {
+ nir_builder_instr_insert(b, &load->instr);
+ return &load->dest.ssa;
+ }
}
static void
@@ -759,7 +811,19 @@ build_explicit_io_store(nir_builder *b, nir_intrinsic_instr *intrin,
assert(value->num_components == 1 ||
value->num_components == intrin->num_components);
store->num_components = value->num_components;
- nir_builder_instr_insert(b, &store->instr);
+
+ assert(value->bit_size % 8 == 0);
+
+ if (addr_format_needs_bounds_check(addr_format)) {
+ const unsigned store_size = (value->bit_size / 8) * store->num_components;
+ nir_push_if(b, addr_is_in_bounds(b, addr, addr_format, store_size));
+
+ nir_builder_instr_insert(b, &store->instr);
+
+ nir_pop_if(b, NULL);
+ } else {
+ nir_builder_instr_insert(b, &store->instr);
+ }
}
static nir_ssa_def *
@@ -802,9 +866,22 @@ build_explicit_io_atomic(nir_builder *b, nir_intrinsic_instr *intrin,
assert(intrin->dest.ssa.num_components == 1);
nir_ssa_dest_init(&atomic->instr, &atomic->dest,
1, intrin->dest.ssa.bit_size, intrin->dest.ssa.name);
- nir_builder_instr_insert(b, &atomic->instr);
- return &atomic->dest.ssa;
+ assert(atomic->dest.ssa.bit_size % 8 == 0);
+
+ if (addr_format_needs_bounds_check(addr_format)) {
+ const unsigned atomic_size = atomic->dest.ssa.bit_size / 8;
+ nir_push_if(b, addr_is_in_bounds(b, addr, addr_format, atomic_size));
+
+ nir_builder_instr_insert(b, &atomic->instr);
+
+ nir_pop_if(b, NULL);
+ return nir_if_phi(b, &atomic->dest.ssa,
+ nir_ssa_undef(b, 1, atomic->dest.ssa.bit_size));
+ } else {
+ nir_builder_instr_insert(b, &atomic->instr);
+ return &atomic->dest.ssa;
+ }
}
static void