tint/exe: Add --allow-non-uniform-derivatives flag
When used with the SPIR-V reader, this will insert a module-scope
diagnostic directive to suppress uniformity violations for derivative
operations.
Bug: tint:1809
Change-Id: I2305265231ccffad49461d194669ba598484e8e0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/117740
Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/src/tint/cmd/main.cc b/src/tint/cmd/main.cc
index a30a133..fa8dbc0 100644
--- a/src/tint/cmd/main.cc
+++ b/src/tint/cmd/main.cc
@@ -103,6 +103,10 @@
bool rename_all = false;
+#if TINT_BUILD_SPV_READER
+ tint::reader::spirv::Options spirv_reader_options;
+#endif
+
std::vector<std::string> transforms;
std::string fxc_path;
@@ -135,6 +139,9 @@
--transform <name list> -- Runs transforms, name list is comma separated
Available transforms:
${transforms} --parse-only -- Stop after parsing the input
+ --allow-non-uniform-derivatives -- When using SPIR-V input, allow non-uniform derivatives by
+ inserting a module-scope directive to suppress any uniformity
+ violations that may be produced.
--disable-workgroup-init -- Disable workgroup memory zero initialization.
--demangle -- Preserve original source names. Demangle them.
Affects AST dumping, and text-based output languages.
@@ -443,6 +450,13 @@
opts->transforms = split_on_comma(args[i]);
} else if (arg == "--parse-only") {
opts->parse_only = true;
+ } else if (arg == "--allow-non-uniform-derivatives") {
+#if TINT_BUILD_SPV_READER
+ opts->spirv_reader_options.allow_non_uniform_derivatives = true;
+#else
+ std::cerr << "Tint not built with the SPIR-V reader enabled" << std::endl;
+ return false;
+#endif
} else if (arg == "--disable-workgroup-init") {
opts->disable_workgroup_init = true;
} else if (arg == "--demangle") {
@@ -1285,7 +1299,8 @@
if (!ReadFile<uint32_t>(options.input_filename, &data)) {
return 1;
}
- program = std::make_unique<tint::Program>(tint::reader::spirv::Parse(data));
+ program = std::make_unique<tint::Program>(
+ tint::reader::spirv::Parse(data, options.spirv_reader_options));
break;
#else
std::cerr << "Tint not built with the SPIR-V reader enabled" << std::endl;
@@ -1309,7 +1324,8 @@
SPV_TEXT_TO_BINARY_OPTION_PRESERVE_NUMERIC_IDS)) {
return 1;
}
- program = std::make_unique<tint::Program>(tint::reader::spirv::Parse(data));
+ program = std::make_unique<tint::Program>(
+ tint::reader::spirv::Parse(data, options.spirv_reader_options));
break;
#else
std::cerr << "Tint not built with the SPIR-V reader enabled" << std::endl;
diff --git a/src/tint/reader/spirv/parser.cc b/src/tint/reader/spirv/parser.cc
index ac43b9e..41e6df3 100644
--- a/src/tint/reader/spirv/parser.cc
+++ b/src/tint/reader/spirv/parser.cc
@@ -27,7 +27,7 @@
namespace tint::reader::spirv {
-Program Parse(const std::vector<uint32_t>& input) {
+Program Parse(const std::vector<uint32_t>& input, const Options& options) {
ParserImpl parser(input);
bool parsed = parser.Parse();
@@ -38,6 +38,13 @@
return Program(std::move(builder));
}
+ if (options.allow_non_uniform_derivatives) {
+ // Suppress errors regarding non-uniform derivative operations if requested, by adding a
+ // diagnostic directive to the module.
+ builder.DiagnosticDirective(ast::DiagnosticSeverity::kOff,
+ builder.Expr("derivative_uniformity"));
+ }
+
// The SPIR-V parser can construct disjoint AST nodes, which is invalid for
// the Resolver. Clone the Program to clean these up.
builder.SetResolveOnBuild(false);
diff --git a/src/tint/reader/spirv/parser.h b/src/tint/reader/spirv/parser.h
index 3641e08..78c80c0d 100644
--- a/src/tint/reader/spirv/parser.h
+++ b/src/tint/reader/spirv/parser.h
@@ -21,13 +21,20 @@
namespace tint::reader::spirv {
+/// Options that control how the SPIR-V parser should behave.
+struct Options {
+ /// Set to `true` to allow calls to derivative builtins in non-uniform control flow.
+ bool allow_non_uniform_derivatives = false;
+};
+
/// Parses the SPIR-V source data, returning the parsed program.
/// If the source data fails to parse then the returned
/// `program.Diagnostics.contains_errors()` will be true, and the
/// `program.Diagnostics()` will describe the error.
/// @param input the source data
+/// @param options the parser options
/// @returns the parsed program
-Program Parse(const std::vector<uint32_t>& input);
+Program Parse(const std::vector<uint32_t>& input, const Options& options = {});
} // namespace tint::reader::spirv
diff --git a/src/tint/reader/spirv/parser_test.cc b/src/tint/reader/spirv/parser_test.cc
index 35cb5da..3f5e370 100644
--- a/src/tint/reader/spirv/parser_test.cc
+++ b/src/tint/reader/spirv/parser_test.cc
@@ -14,7 +14,9 @@
#include "src/tint/reader/spirv/parser.h"
+#include "gmock/gmock.h"
#include "gtest/gtest.h"
+#include "src/tint/reader/spirv/spirv_tools_helpers_test.h"
namespace tint::reader::spirv {
namespace {
@@ -29,6 +31,54 @@
EXPECT_EQ(errs, "error: line:0: Invalid SPIR-V magic number.\n");
}
+constexpr auto kShaderWithNonUniformDerivative = R"(
+ OpCapability Shader
+ OpMemoryModel Logical GLSL450
+ OpEntryPoint Fragment %foo "foo" %x
+ OpExecutionMode %foo OriginUpperLeft
+ OpDecorate %x Location 0
+ %float = OpTypeFloat 32
+%_ptr_Input_float = OpTypePointer Input %float
+ %x = OpVariable %_ptr_Input_float Input
+ %void = OpTypeVoid
+ %float_0 = OpConstantNull %float
+ %bool = OpTypeBool
+ %func_type = OpTypeFunction %void
+ %foo = OpFunction %void None %func_type
+ %foo_start = OpLabel
+ %x_value = OpLoad %float %x
+ %condition = OpFOrdGreaterThan %bool %x_value %float_0
+ OpSelectionMerge %merge None
+ OpBranchConditional %condition %true_branch %merge
+%true_branch = OpLabel
+ %result = OpDPdx %float %x_value
+ OpBranch %merge
+ %merge = OpLabel
+ OpReturn
+ OpFunctionEnd
+)";
+
+TEST_F(ParserTest, AllowNonUniformDerivatives_False) {
+ auto spv = test::Assemble(kShaderWithNonUniformDerivative);
+ Options options;
+ options.allow_non_uniform_derivatives = false;
+ auto program = Parse(spv, options);
+ auto errs = diag::Formatter().format(program.Diagnostics());
+ // TODO(jrprice): This will become EXPECT_FALSE.
+ EXPECT_TRUE(program.IsValid()) << errs;
+ EXPECT_THAT(errs, ::testing::HasSubstr("'dpdx' must only be called from uniform control flow"));
+}
+
+TEST_F(ParserTest, AllowNonUniformDerivatives_True) {
+ auto spv = test::Assemble(kShaderWithNonUniformDerivative);
+ Options options;
+ options.allow_non_uniform_derivatives = true;
+ auto program = Parse(spv, options);
+ auto errs = diag::Formatter().format(program.Diagnostics());
+ EXPECT_TRUE(program.IsValid()) << errs;
+ EXPECT_EQ(program.Diagnostics().count(), 0u) << errs;
+}
+
// TODO(dneto): uint32 vec, valid SPIR-V
// TODO(dneto): uint32 vec, invalid SPIR-V
