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Source file src/runtime/iface_test.go

Documentation: runtime

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime_test
     6  
     7  import (
     8  	"runtime"
     9  	"testing"
    10  )
    11  
    12  type I1 interface {
    13  	Method1()
    14  }
    15  
    16  type I2 interface {
    17  	Method1()
    18  	Method2()
    19  }
    20  
    21  type TS uint16
    22  type TM uintptr
    23  type TL [2]uintptr
    24  
    25  func (TS) Method1() {}
    26  func (TS) Method2() {}
    27  func (TM) Method1() {}
    28  func (TM) Method2() {}
    29  func (TL) Method1() {}
    30  func (TL) Method2() {}
    31  
    32  type T8 uint8
    33  type T16 uint16
    34  type T32 uint32
    35  type T64 uint64
    36  type Tstr string
    37  type Tslice []byte
    38  
    39  func (T8) Method1()     {}
    40  func (T16) Method1()    {}
    41  func (T32) Method1()    {}
    42  func (T64) Method1()    {}
    43  func (Tstr) Method1()   {}
    44  func (Tslice) Method1() {}
    45  
    46  var (
    47  	e  any
    48  	e_ any
    49  	i1 I1
    50  	i2 I2
    51  	ts TS
    52  	tm TM
    53  	tl TL
    54  	ok bool
    55  )
    56  
    57  // Issue 9370
    58  func TestCmpIfaceConcreteAlloc(t *testing.T) {
    59  	if runtime.Compiler != "gc" {
    60  		t.Skip("skipping on non-gc compiler")
    61  	}
    62  
    63  	n := testing.AllocsPerRun(1, func() {
    64  		_ = e == ts
    65  		_ = i1 == ts
    66  		_ = e == 1
    67  	})
    68  
    69  	if n > 0 {
    70  		t.Fatalf("iface cmp allocs=%v; want 0", n)
    71  	}
    72  }
    73  
    74  func BenchmarkEqEfaceConcrete(b *testing.B) {
    75  	for i := 0; i < b.N; i++ {
    76  		_ = e == ts
    77  	}
    78  }
    79  
    80  func BenchmarkEqIfaceConcrete(b *testing.B) {
    81  	for i := 0; i < b.N; i++ {
    82  		_ = i1 == ts
    83  	}
    84  }
    85  
    86  func BenchmarkNeEfaceConcrete(b *testing.B) {
    87  	for i := 0; i < b.N; i++ {
    88  		_ = e != ts
    89  	}
    90  }
    91  
    92  func BenchmarkNeIfaceConcrete(b *testing.B) {
    93  	for i := 0; i < b.N; i++ {
    94  		_ = i1 != ts
    95  	}
    96  }
    97  
    98  func BenchmarkConvT2EByteSized(b *testing.B) {
    99  	b.Run("bool", func(b *testing.B) {
   100  		for i := 0; i < b.N; i++ {
   101  			e = yes
   102  		}
   103  	})
   104  	b.Run("uint8", func(b *testing.B) {
   105  		for i := 0; i < b.N; i++ {
   106  			e = eight8
   107  		}
   108  	})
   109  }
   110  
   111  func BenchmarkConvT2ESmall(b *testing.B) {
   112  	for i := 0; i < b.N; i++ {
   113  		e = ts
   114  	}
   115  }
   116  
   117  func BenchmarkConvT2EUintptr(b *testing.B) {
   118  	for i := 0; i < b.N; i++ {
   119  		e = tm
   120  	}
   121  }
   122  
   123  func BenchmarkConvT2ELarge(b *testing.B) {
   124  	for i := 0; i < b.N; i++ {
   125  		e = tl
   126  	}
   127  }
   128  
   129  func BenchmarkConvT2ISmall(b *testing.B) {
   130  	for i := 0; i < b.N; i++ {
   131  		i1 = ts
   132  	}
   133  }
   134  
   135  func BenchmarkConvT2IUintptr(b *testing.B) {
   136  	for i := 0; i < b.N; i++ {
   137  		i1 = tm
   138  	}
   139  }
   140  
   141  func BenchmarkConvT2ILarge(b *testing.B) {
   142  	for i := 0; i < b.N; i++ {
   143  		i1 = tl
   144  	}
   145  }
   146  
   147  func BenchmarkConvI2E(b *testing.B) {
   148  	i2 = tm
   149  	for i := 0; i < b.N; i++ {
   150  		e = i2
   151  	}
   152  }
   153  
   154  func BenchmarkConvI2I(b *testing.B) {
   155  	i2 = tm
   156  	for i := 0; i < b.N; i++ {
   157  		i1 = i2
   158  	}
   159  }
   160  
   161  func BenchmarkAssertE2T(b *testing.B) {
   162  	e = tm
   163  	for i := 0; i < b.N; i++ {
   164  		tm = e.(TM)
   165  	}
   166  }
   167  
   168  func BenchmarkAssertE2TLarge(b *testing.B) {
   169  	e = tl
   170  	for i := 0; i < b.N; i++ {
   171  		tl = e.(TL)
   172  	}
   173  }
   174  
   175  func BenchmarkAssertE2I(b *testing.B) {
   176  	e = tm
   177  	for i := 0; i < b.N; i++ {
   178  		i1 = e.(I1)
   179  	}
   180  }
   181  
   182  func BenchmarkAssertI2T(b *testing.B) {
   183  	i1 = tm
   184  	for i := 0; i < b.N; i++ {
   185  		tm = i1.(TM)
   186  	}
   187  }
   188  
   189  func BenchmarkAssertI2I(b *testing.B) {
   190  	i1 = tm
   191  	for i := 0; i < b.N; i++ {
   192  		i2 = i1.(I2)
   193  	}
   194  }
   195  
   196  func BenchmarkAssertI2E(b *testing.B) {
   197  	i1 = tm
   198  	for i := 0; i < b.N; i++ {
   199  		e = i1.(any)
   200  	}
   201  }
   202  
   203  func BenchmarkAssertE2E(b *testing.B) {
   204  	e = tm
   205  	for i := 0; i < b.N; i++ {
   206  		e_ = e
   207  	}
   208  }
   209  
   210  func BenchmarkAssertE2T2(b *testing.B) {
   211  	e = tm
   212  	for i := 0; i < b.N; i++ {
   213  		tm, ok = e.(TM)
   214  	}
   215  }
   216  
   217  func BenchmarkAssertE2T2Blank(b *testing.B) {
   218  	e = tm
   219  	for i := 0; i < b.N; i++ {
   220  		_, ok = e.(TM)
   221  	}
   222  }
   223  
   224  func BenchmarkAssertI2E2(b *testing.B) {
   225  	i1 = tm
   226  	for i := 0; i < b.N; i++ {
   227  		e, ok = i1.(any)
   228  	}
   229  }
   230  
   231  func BenchmarkAssertI2E2Blank(b *testing.B) {
   232  	i1 = tm
   233  	for i := 0; i < b.N; i++ {
   234  		_, ok = i1.(any)
   235  	}
   236  }
   237  
   238  func BenchmarkAssertE2E2(b *testing.B) {
   239  	e = tm
   240  	for i := 0; i < b.N; i++ {
   241  		e_, ok = e.(any)
   242  	}
   243  }
   244  
   245  func BenchmarkAssertE2E2Blank(b *testing.B) {
   246  	e = tm
   247  	for i := 0; i < b.N; i++ {
   248  		_, ok = e.(any)
   249  	}
   250  }
   251  
   252  func TestNonEscapingConvT2E(t *testing.T) {
   253  	m := make(map[any]bool)
   254  	m[42] = true
   255  	if !m[42] {
   256  		t.Fatalf("42 is not present in the map")
   257  	}
   258  	if m[0] {
   259  		t.Fatalf("0 is present in the map")
   260  	}
   261  
   262  	n := testing.AllocsPerRun(1000, func() {
   263  		if m[0] {
   264  			t.Fatalf("0 is present in the map")
   265  		}
   266  	})
   267  	if n != 0 {
   268  		t.Fatalf("want 0 allocs, got %v", n)
   269  	}
   270  }
   271  
   272  func TestNonEscapingConvT2I(t *testing.T) {
   273  	m := make(map[I1]bool)
   274  	m[TM(42)] = true
   275  	if !m[TM(42)] {
   276  		t.Fatalf("42 is not present in the map")
   277  	}
   278  	if m[TM(0)] {
   279  		t.Fatalf("0 is present in the map")
   280  	}
   281  
   282  	n := testing.AllocsPerRun(1000, func() {
   283  		if m[TM(0)] {
   284  			t.Fatalf("0 is present in the map")
   285  		}
   286  	})
   287  	if n != 0 {
   288  		t.Fatalf("want 0 allocs, got %v", n)
   289  	}
   290  }
   291  
   292  func TestZeroConvT2x(t *testing.T) {
   293  	tests := []struct {
   294  		name string
   295  		fn   func()
   296  	}{
   297  		{name: "E8", fn: func() { e = eight8 }},  // any byte-sized value does not allocate
   298  		{name: "E16", fn: func() { e = zero16 }}, // zero values do not allocate
   299  		{name: "E32", fn: func() { e = zero32 }},
   300  		{name: "E64", fn: func() { e = zero64 }},
   301  		{name: "Estr", fn: func() { e = zerostr }},
   302  		{name: "Eslice", fn: func() { e = zeroslice }},
   303  		{name: "Econstflt", fn: func() { e = 99.0 }}, // constants do not allocate
   304  		{name: "Econststr", fn: func() { e = "change" }},
   305  		{name: "I8", fn: func() { i1 = eight8I }},
   306  		{name: "I16", fn: func() { i1 = zero16I }},
   307  		{name: "I32", fn: func() { i1 = zero32I }},
   308  		{name: "I64", fn: func() { i1 = zero64I }},
   309  		{name: "Istr", fn: func() { i1 = zerostrI }},
   310  		{name: "Islice", fn: func() { i1 = zerosliceI }},
   311  	}
   312  
   313  	for _, test := range tests {
   314  		t.Run(test.name, func(t *testing.T) {
   315  			n := testing.AllocsPerRun(1000, test.fn)
   316  			if n != 0 {
   317  				t.Errorf("want zero allocs, got %v", n)
   318  			}
   319  		})
   320  	}
   321  }
   322  
   323  var (
   324  	eight8  uint8 = 8
   325  	eight8I T8    = 8
   326  	yes     bool  = true
   327  
   328  	zero16     uint16 = 0
   329  	zero16I    T16    = 0
   330  	one16      uint16 = 1
   331  	thousand16 uint16 = 1000
   332  
   333  	zero32     uint32 = 0
   334  	zero32I    T32    = 0
   335  	one32      uint32 = 1
   336  	thousand32 uint32 = 1000
   337  
   338  	zero64     uint64 = 0
   339  	zero64I    T64    = 0
   340  	one64      uint64 = 1
   341  	thousand64 uint64 = 1000
   342  
   343  	zerostr  string = ""
   344  	zerostrI Tstr   = ""
   345  	nzstr    string = "abc"
   346  
   347  	zeroslice  []byte = nil
   348  	zerosliceI Tslice = nil
   349  	nzslice    []byte = []byte("abc")
   350  
   351  	zerobig [512]byte
   352  	nzbig   [512]byte = [512]byte{511: 1}
   353  )
   354  
   355  func BenchmarkConvT2Ezero(b *testing.B) {
   356  	b.Run("zero", func(b *testing.B) {
   357  		b.Run("16", func(b *testing.B) {
   358  			for i := 0; i < b.N; i++ {
   359  				e = zero16
   360  			}
   361  		})
   362  		b.Run("32", func(b *testing.B) {
   363  			for i := 0; i < b.N; i++ {
   364  				e = zero32
   365  			}
   366  		})
   367  		b.Run("64", func(b *testing.B) {
   368  			for i := 0; i < b.N; i++ {
   369  				e = zero64
   370  			}
   371  		})
   372  		b.Run("str", func(b *testing.B) {
   373  			for i := 0; i < b.N; i++ {
   374  				e = zerostr
   375  			}
   376  		})
   377  		b.Run("slice", func(b *testing.B) {
   378  			for i := 0; i < b.N; i++ {
   379  				e = zeroslice
   380  			}
   381  		})
   382  		b.Run("big", func(b *testing.B) {
   383  			for i := 0; i < b.N; i++ {
   384  				e = zerobig
   385  			}
   386  		})
   387  	})
   388  	b.Run("nonzero", func(b *testing.B) {
   389  		b.Run("str", func(b *testing.B) {
   390  			for i := 0; i < b.N; i++ {
   391  				e = nzstr
   392  			}
   393  		})
   394  		b.Run("slice", func(b *testing.B) {
   395  			for i := 0; i < b.N; i++ {
   396  				e = nzslice
   397  			}
   398  		})
   399  		b.Run("big", func(b *testing.B) {
   400  			for i := 0; i < b.N; i++ {
   401  				e = nzbig
   402  			}
   403  		})
   404  	})
   405  	b.Run("smallint", func(b *testing.B) {
   406  		b.Run("16", func(b *testing.B) {
   407  			for i := 0; i < b.N; i++ {
   408  				e = one16
   409  			}
   410  		})
   411  		b.Run("32", func(b *testing.B) {
   412  			for i := 0; i < b.N; i++ {
   413  				e = one32
   414  			}
   415  		})
   416  		b.Run("64", func(b *testing.B) {
   417  			for i := 0; i < b.N; i++ {
   418  				e = one64
   419  			}
   420  		})
   421  	})
   422  	b.Run("largeint", func(b *testing.B) {
   423  		b.Run("16", func(b *testing.B) {
   424  			for i := 0; i < b.N; i++ {
   425  				e = thousand16
   426  			}
   427  		})
   428  		b.Run("32", func(b *testing.B) {
   429  			for i := 0; i < b.N; i++ {
   430  				e = thousand32
   431  			}
   432  		})
   433  		b.Run("64", func(b *testing.B) {
   434  			for i := 0; i < b.N; i++ {
   435  				e = thousand64
   436  			}
   437  		})
   438  	})
   439  }
   440  

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