diff --git a/go/analysis/analysis.go b/go/analysis/analysis.go
index 21baa02a..4d8a6e5e 100644
--- a/go/analysis/analysis.go
+++ b/go/analysis/analysis.go
@@ -87,6 +87,7 @@ type Pass struct {
 	OtherFiles []string       // names of non-Go files of this package
 	Pkg        *types.Package // type information about the package
 	TypesInfo  *types.Info    // type information about the syntax trees
+	TypesSizes types.Sizes    // function for computing sizes of types
 
 	// Report reports a Diagnostic, a finding about a specific location
 	// in the analyzed source code such as a potential mistake.
diff --git a/go/analysis/internal/checker/checker.go b/go/analysis/internal/checker/checker.go
index e70a5133..0d36e0bf 100644
--- a/go/analysis/internal/checker/checker.go
+++ b/go/analysis/internal/checker/checker.go
@@ -492,6 +492,7 @@ func (act *action) execOnce() {
 		OtherFiles:        act.pkg.OtherFiles,
 		Pkg:               act.pkg.Types,
 		TypesInfo:         act.pkg.TypesInfo,
+		TypesSizes:        act.pkg.TypesSizes,
 		ResultOf:          inputs,
 		Report:            func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
 		ImportObjectFact:  act.importObjectFact,
diff --git a/go/analysis/passes/asmdecl/asmdecl.go b/go/analysis/passes/asmdecl/asmdecl.go
index dce1ef7b..6403d778 100644
--- a/go/analysis/passes/asmdecl/asmdecl.go
+++ b/go/analysis/passes/asmdecl/asmdecl.go
@@ -114,7 +114,8 @@ func init() {
 			// library we cannot assume types.SizesFor is consistent with arches.
 			// For now, assume 64-bit norms and print a warning.
 			// But this warning should really be deferred until we attempt to use
-			// arch, which is very unlikely.
+			// arch, which is very unlikely. Better would be
+			// to defer size computation until we have Pass.TypesSizes.
 			arch.sizes = types.SizesFor("gc", "amd64")
 			log.Printf("unknown architecture %s", arch.name)
 		}
diff --git a/go/analysis/passes/cgocall/cgocall.go b/go/analysis/passes/cgocall/cgocall.go
index 993f1ce3..1e4fac85 100644
--- a/go/analysis/passes/cgocall/cgocall.go
+++ b/go/analysis/passes/cgocall/cgocall.go
@@ -9,7 +9,6 @@ package cgocall
 import (
 	"fmt"
 	"go/ast"
-	"go/build"
 	"go/format"
 	"go/parser"
 	"go/token"
@@ -45,7 +44,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 		return nil, nil // doesn't use cgo
 	}
 
-	cgofiles, info, err := typeCheckCgoSourceFiles(pass.Fset, pass.Pkg, pass.Files, pass.TypesInfo)
+	cgofiles, info, err := typeCheckCgoSourceFiles(pass.Fset, pass.Pkg, pass.Files, pass.TypesInfo, pass.TypesSizes)
 	if err != nil {
 		return nil, err
 	}
@@ -171,7 +170,7 @@ func checkCgo(fset *token.FileSet, f *ast.File, info *types.Info, reportf func(t
 // limited ourselves here to preserving function bodies and initializer
 // expressions since that is all that the cgocall analyzer needs.
 //
-func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*ast.File, info *types.Info) ([]*ast.File, *types.Info, error) {
+func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*ast.File, info *types.Info, sizes types.Sizes) ([]*ast.File, *types.Info, error) {
 	const thispkg = "·this·"
 
 	// Which files are cgo files?
@@ -269,8 +268,7 @@ func typeCheckCgoSourceFiles(fset *token.FileSet, pkg *types.Package, files []*a
 		Importer: importerFunc(func(path string) (*types.Package, error) {
 			return importMap[path], nil
 		}),
-		// TODO(adonovan): Sizes should probably be provided by analysis.Pass.
-		Sizes: types.SizesFor("gc", build.Default.GOARCH),
+		Sizes: sizes,
 		Error: func(error) {}, // ignore errors (e.g. unused import)
 	}
 
diff --git a/go/analysis/passes/printf/types.go b/go/analysis/passes/printf/types.go
index e8810464..2eb6dc74 100644
--- a/go/analysis/passes/printf/types.go
+++ b/go/analysis/passes/printf/types.go
@@ -2,7 +2,6 @@ package printf
 
 import (
 	"go/ast"
-	"go/build"
 	"go/types"
 
 	"golang.org/x/tools/go/analysis"
@@ -235,5 +234,3 @@ func matchStructArgType(pass *analysis.Pass, t printfArgType, typ *types.Struct,
 	}
 	return true
 }
-
-var archSizes = types.SizesFor("gc", build.Default.GOARCH)
diff --git a/go/analysis/passes/shift/shift.go b/go/analysis/passes/shift/shift.go
index 56b150b2..39f54573 100644
--- a/go/analysis/passes/shift/shift.go
+++ b/go/analysis/passes/shift/shift.go
@@ -12,10 +12,8 @@ package shift
 
 import (
 	"go/ast"
-	"go/build"
 	"go/constant"
 	"go/token"
-	"go/types"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
@@ -93,36 +91,9 @@ func checkLongShift(pass *analysis.Pass, node ast.Node, x, y ast.Expr) {
 	if t == nil {
 		return
 	}
-	b, ok := t.Underlying().(*types.Basic)
-	if !ok {
-		return
-	}
-	var size int64
-	switch b.Kind() {
-	case types.Uint8, types.Int8:
-		size = 8
-	case types.Uint16, types.Int16:
-		size = 16
-	case types.Uint32, types.Int32:
-		size = 32
-	case types.Uint64, types.Int64:
-		size = 64
-	case types.Int, types.Uint:
-		size = uintBitSize
-	case types.Uintptr:
-		size = uintptrBitSize
-	default:
-		return
-	}
+	size := 8 * pass.TypesSizes.Sizeof(t)
 	if amt >= size {
 		ident := analysisutil.Format(pass.Fset, x)
 		pass.Reportf(node.Pos(), "%s (%d bits) too small for shift of %d", ident, size, amt)
 	}
 }
-
-var (
-	uintBitSize    = 8 * archSizes.Sizeof(types.Typ[types.Uint])
-	uintptrBitSize = 8 * archSizes.Sizeof(types.Typ[types.Uintptr])
-)
-
-var archSizes = types.SizesFor("gc", build.Default.GOARCH)
diff --git a/go/analysis/unitchecker/unitchecker.go b/go/analysis/unitchecker/unitchecker.go
index 76dabc28..ba2e66fe 100644
--- a/go/analysis/unitchecker/unitchecker.go
+++ b/go/analysis/unitchecker/unitchecker.go
@@ -329,6 +329,7 @@ func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]re
 				OtherFiles:        cfg.NonGoFiles,
 				Pkg:               pkg,
 				TypesInfo:         info,
+				TypesSizes:        tc.Sizes,
 				ResultOf:          inputs,
 				Report:            func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
 				ImportObjectFact:  facts.ImportObjectFact,
diff --git a/go/packages/packages.go b/go/packages/packages.go
index e69ddfcb..5da437fc 100644
--- a/go/packages/packages.go
+++ b/go/packages/packages.go
@@ -250,6 +250,9 @@ type Package struct {
 	// TypesInfo provides type information about the package's syntax trees.
 	// It is set only when Syntax is set.
 	TypesInfo *types.Info
+
+	// TypesSizes provides the effective size function for types in TypesInfo.
+	TypesSizes types.Sizes
 }
 
 // An Error describes a problem with a package's metadata, syntax, or types.
@@ -582,6 +585,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		lpkg.Fset = ld.Fset
 		lpkg.Syntax = []*ast.File{}
 		lpkg.TypesInfo = new(types.Info)
+		lpkg.TypesSizes = ld.sizes
 		return
 	}
 
@@ -669,6 +673,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		Scopes:     make(map[ast.Node]*types.Scope),
 		Selections: make(map[*ast.SelectorExpr]*types.Selection),
 	}
+	lpkg.TypesSizes = ld.sizes
 
 	importer := importerFunc(func(path string) (*types.Package, error) {
 		if path == "unsafe" {