From 4349775a30600906f5811ba7c743a5c22bdb3d7d Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Wed, 19 Jun 2019 15:13:53 +0000 Subject: [PATCH] compiler: optimize string concatenations runtime.concatstring{2,3,4,5} are just wrappers of concatstrings. These wrappers don't provide any benefit, at least in the C calling convention we use, where passing arrays by value isn't an efficient thing. Change it to always use concatstrings. Also, the cap field of the slice passed to concatstrings is not necessary. So change it to pass a pointer and a length directly, which is more efficient than passing a slice header by value. Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/182539 From-SVN: r272476 --- gcc/go/gofrontend/MERGE | 2 +- gcc/go/gofrontend/expressions.cc | 68 ++++++++------------------------ gcc/go/gofrontend/runtime.def | 12 +----- libgo/go/runtime/string.go | 24 ++--------- 4 files changed, 23 insertions(+), 83 deletions(-) diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index e62501f4dfb..3b0cff742eb 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -0e4aa31b26a20b6a6a2ca102b85ba8c8b8cdf876 +7822080a6e226b1e5872e2fcefac30f666f4cc1e The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/gcc/go/gofrontend/expressions.cc b/gcc/go/gofrontend/expressions.cc index 766864a535d..864b62df3b1 100644 --- a/gcc/go/gofrontend/expressions.cc +++ b/gcc/go/gofrontend/expressions.cc @@ -7442,7 +7442,7 @@ String_concat_expression::do_check_types(Gogo*) Expression* String_concat_expression::do_flatten(Gogo*, Named_object*, - Statement_inserter*) + Statement_inserter* inserter) { if (this->is_error_expression()) return this; @@ -7497,56 +7497,22 @@ String_concat_expression::do_flatten(Gogo*, Named_object*, } if (buf == NULL) buf = Expression::make_nil(loc); - Expression* call; - switch (this->exprs_->size()) - { - case 0: case 1: - go_unreachable(); - - case 2: case 3: case 4: case 5: - { - Expression* len = Expression::make_integer_ul(this->exprs_->size(), - NULL, loc); - Array_type* arg_type = Type::make_array_type(type, len); - arg_type->set_is_array_incomparable(); - Expression* arg = - Expression::make_array_composite_literal(arg_type, this->exprs_, - loc); - Runtime::Function code; - switch (this->exprs_->size()) - { - default: - go_unreachable(); - case 2: - code = Runtime::CONCATSTRING2; - break; - case 3: - code = Runtime::CONCATSTRING3; - break; - case 4: - code = Runtime::CONCATSTRING4; - break; - case 5: - code = Runtime::CONCATSTRING5; - break; - } - call = Runtime::make_call(code, loc, 2, buf, arg); - } - break; - - default: - { - Type* arg_type = Type::make_array_type(type, NULL); - Slice_construction_expression* sce = - Expression::make_slice_composite_literal(arg_type, this->exprs_, - loc); - sce->set_storage_does_not_escape(); - call = Runtime::make_call(Runtime::CONCATSTRINGS, loc, 2, buf, - sce); - } - break; - } - + go_assert(this->exprs_->size() > 1); + Expression* len = + Expression::make_integer_ul(this->exprs_->size(), NULL, loc); + Array_type* array_type = Type::make_array_type(type, len); + array_type->set_is_array_incomparable(); + Expression* array = + Expression::make_array_composite_literal(array_type, this->exprs_, + loc); + Temporary_statement* ts = + Statement::make_temporary(array_type, array, loc); + inserter->insert(ts); + Expression* ref = Expression::make_temporary_reference(ts, loc); + ref = Expression::make_unary(OPERATOR_AND, ref, loc); + Expression* call = + Runtime::make_call(Runtime::CONCATSTRINGS, loc, 3, buf, + ref, len->copy()); return Expression::make_cast(type, call, loc); } diff --git a/gcc/go/gofrontend/runtime.def b/gcc/go/gofrontend/runtime.def index 34c86e8aafc..c81ab79cc0f 100644 --- a/gcc/go/gofrontend/runtime.def +++ b/gcc/go/gofrontend/runtime.def @@ -36,16 +36,8 @@ DEF_GO_RUNTIME(DECODERUNE, "runtime.decoderune", P2(STRING, INT), R2(RUNE, INT)) // Concatenate strings. -DEF_GO_RUNTIME(CONCATSTRINGS, "runtime.concatstrings", P2(POINTER, SLICE), - R1(STRING)) -DEF_GO_RUNTIME(CONCATSTRING2, "runtime.concatstring2", - P2(POINTER, ARRAY2STRING), R1(STRING)) -DEF_GO_RUNTIME(CONCATSTRING3, "runtime.concatstring3", - P2(POINTER, ARRAY3STRING), R1(STRING)) -DEF_GO_RUNTIME(CONCATSTRING4, "runtime.concatstring4", - P2(POINTER, ARRAY4STRING), R1(STRING)) -DEF_GO_RUNTIME(CONCATSTRING5, "runtime.concatstring5", - P2(POINTER, ARRAY5STRING), R1(STRING)) +DEF_GO_RUNTIME(CONCATSTRINGS, "runtime.concatstrings", + P3(POINTER, POINTER, INT), R1(STRING)) // Compare two strings for equality. DEF_GO_RUNTIME(EQSTRING, "runtime.eqstring", P2(STRING, STRING), R1(BOOL)) diff --git a/libgo/go/runtime/string.go b/libgo/go/runtime/string.go index eac94bf6a8a..9bcfc9961c8 100644 --- a/libgo/go/runtime/string.go +++ b/libgo/go/runtime/string.go @@ -13,10 +13,6 @@ import ( // themselves, so that the compiler will export them. // //go:linkname concatstrings runtime.concatstrings -//go:linkname concatstring2 runtime.concatstring2 -//go:linkname concatstring3 runtime.concatstring3 -//go:linkname concatstring4 runtime.concatstring4 -//go:linkname concatstring5 runtime.concatstring5 //go:linkname slicebytetostring runtime.slicebytetostring //go:linkname slicebytetostringtmp runtime.slicebytetostringtmp //go:linkname stringtoslicebyte runtime.stringtoslicebyte @@ -38,7 +34,9 @@ type tmpBuf [tmpStringBufSize]byte // If buf != nil, the compiler has determined that the result does not // escape the calling function, so the string data can be stored in buf // if small enough. -func concatstrings(buf *tmpBuf, a []string) string { +func concatstrings(buf *tmpBuf, p *string, n int) string { + var a []string + *(*slice)(unsafe.Pointer(&a)) = slice{unsafe.Pointer(p), n, n} // idx := 0 l := 0 count := 0 @@ -73,22 +71,6 @@ func concatstrings(buf *tmpBuf, a []string) string { return s } -func concatstring2(buf *tmpBuf, a [2]string) string { - return concatstrings(buf, a[:]) -} - -func concatstring3(buf *tmpBuf, a [3]string) string { - return concatstrings(buf, a[:]) -} - -func concatstring4(buf *tmpBuf, a [4]string) string { - return concatstrings(buf, a[:]) -} - -func concatstring5(buf *tmpBuf, a [5]string) string { - return concatstrings(buf, a[:]) -} - // Buf is a fixed-size buffer for the result, // it is not nil if the result does not escape. func slicebytetostring(buf *tmpBuf, b []byte) (str string) { -- 2.30.2