Publish Soong configuration to Make variables

For configuration like TARGET_GLOBAL_CFLAGS, it would be good to have
Make and Soong use the same values. This change adds an interface for
packages like cc to verify the current value of make variables match the
Soong equivalents, and once they're satisfied with the results, remove
the make definition and use the value from Soong.

The cc implementation exports a few variables currently that I expect to
match between both implementations in all cases. It also checks
{CLANG,}{HOST,TARGET}_GLOBAL_{C,LD}FLAGS, which should be mostly similar
between make and soong now.

Bug: 23566674
Change-Id: Idc8582ef31ace11a8baefcf525c3683f08a573aa

3 files changed, 355 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
index 831b703f..c1d664f4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -96,6 +96,7 @@ bootstrap_go_package {
         "common/defs.go",
         "common/env.go",
         "common/glob.go",
+        "common/makevars.go",
         "common/module.go",
         "common/mutator.go",
         "common/package_ctx.go",
@@ -124,6 +125,7 @@ bootstrap_go_package {
         "cc/cc.go",
         "cc/clang.go",
         "cc/gen.go",
+        "cc/makevars.go",
         "cc/sanitize.go",
         "cc/stl.go",
         "cc/toolchain.go",
diff --git a/cc/makevars.go b/cc/makevars.go
new file mode 100644
index 00000000..00a4f712
--- /dev/null
+++ b/cc/makevars.go
@@ -0,0 +1,111 @@
+// Copyright 2016 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cc
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	"android/soong/common"
+)
+
+func init() {
+	common.RegisterMakeVarsProvider(pctx, makeVarsProvider)
+}
+
+func makeVarsProvider(ctx common.MakeVarsContext) {
+	ctx.Strict("LLVM_PREBUILTS_VERSION", "${clangVersion}")
+	ctx.Strict("LLVM_PREBUILTS_BASE", "${clangBase}")
+
+	hostType := common.CurrentHostType()
+	arches := ctx.Config().HostArches[hostType]
+	makeVarsToolchain(ctx, "", common.Host, hostType, arches[0])
+	if len(arches) > 1 {
+		makeVarsToolchain(ctx, "2ND_", common.Host, hostType, arches[1])
+	}
+
+	if winArches, ok := ctx.Config().HostArches[common.Windows]; ok {
+		makeVarsToolchain(ctx, "", common.Host, common.Windows, winArches[0])
+		if len(winArches) > 1 {
+			makeVarsToolchain(ctx, "2ND_", common.Host, common.Windows, winArches[1])
+		}
+	}
+
+	arches = ctx.Config().DeviceArches
+	makeVarsToolchain(ctx, "", common.Device, common.NoHostType, arches[0])
+	if len(arches) > 1 {
+		makeVarsToolchain(ctx, "2ND_", common.Device, common.NoHostType, arches[1])
+	}
+}
+
+func makeVarsToolchain(ctx common.MakeVarsContext, secondPrefix string,
+	hod common.HostOrDevice, ht common.HostType, arch common.Arch) {
+	var typePrefix string
+	if hod.Host() {
+		if ht == common.Windows {
+			typePrefix = "HOST_CROSS_"
+		} else {
+			typePrefix = "HOST_"
+		}
+	} else {
+		typePrefix = "TARGET_"
+	}
+	makePrefix := secondPrefix + typePrefix
+
+	toolchain := toolchainFactories[hod][ht][arch.ArchType](arch)
+
+	globalCflags := fmt.Sprintf("${commonGlobalCflags} ${%sGlobalCflags}", hod)
+
+	ctx.CheckSorted(makePrefix+"GLOBAL_CFLAGS", strings.Join([]string{
+		toolchain.ToolchainCflags(),
+		globalCflags,
+		toolchain.Cflags(),
+	}, " "))
+	ctx.CheckSorted(makePrefix+"GLOBAL_LDFLAGS", strings.Join([]string{
+		toolchain.ToolchainLdflags(),
+		toolchain.Ldflags(),
+	}, " "))
+
+	if toolchain.ClangSupported() {
+		clangPrefix := secondPrefix + "CLANG_" + typePrefix
+		clangExtras := "-target " + toolchain.ClangTriple() + " -B" + filepath.Join(toolchain.GccRoot(), toolchain.GccTriple(), "bin")
+
+		globalClangCflags := fmt.Sprintf("${commonClangGlobalCflags} ${clangExtraCflags} ${%sClangGlobalCflags}", hod)
+
+		ctx.CheckSorted(clangPrefix+"GLOBAL_CFLAGS", strings.Join([]string{
+			toolchain.ToolchainClangCflags(),
+			globalClangCflags,
+			toolchain.ClangCflags(),
+			clangExtras,
+		}, " "))
+		ctx.CheckSorted(clangPrefix+"GLOBAL_LDFLAGS", strings.Join([]string{
+			toolchain.ToolchainClangLdflags(),
+			toolchain.ClangLdflags(),
+			clangExtras,
+		}, " "))
+	}
+
+	ctx.Strict(makePrefix+"CC", gccCmd(toolchain, "gcc"))
+	ctx.Strict(makePrefix+"CXX", gccCmd(toolchain, "g++"))
+
+	if ht == common.Darwin {
+		ctx.Strict(makePrefix+"AR", "${macArPath}")
+	} else {
+		ctx.Strict(makePrefix+"AR", gccCmd(toolchain, "ar"))
+		ctx.Strict(makePrefix+"READELF", gccCmd(toolchain, "readelf"))
+		ctx.Strict(makePrefix+"NM", gccCmd(toolchain, "nm"))
+	}
+}
diff --git a/common/makevars.go b/common/makevars.go
new file mode 100644
index 00000000..ad4f6d46
--- /dev/null
+++ b/common/makevars.go
@@ -0,0 +1,242 @@
+// Copyright 2016 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package common
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"android/soong"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+)
+
+///////////////////////////////////////////////////////////////////////////////
+// Interface for other packages to use to declare make variables
+type MakeVarsContext interface {
+	Config() Config
+
+	// Verify the make variable matches the Soong version, fail the build
+	// if it does not. If the make variable is empty, just set it.
+	Strict(name, ninjaStr string)
+	// Check to see if the make variable matches the Soong version, warn if
+	// it does not. If the make variable is empty, just set it.
+	Check(name, ninjaStr string)
+
+	// These are equivalent to the above, but sort the make and soong
+	// variables before comparing them. They also show the unique entries
+	// in each list when displaying the difference, instead of the entire
+	// string.
+	StrictSorted(name, ninjaStr string)
+	CheckSorted(name, ninjaStr string)
+}
+
+type MakeVarsProvider func(ctx MakeVarsContext)
+
+func RegisterMakeVarsProvider(pctx blueprint.PackageContext, provider MakeVarsProvider) {
+	makeVarsProviders = append(makeVarsProviders, makeVarsProvider{pctx, provider})
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+func init() {
+	soong.RegisterSingletonType("makevars", makeVarsSingletonFunc)
+}
+
+func makeVarsSingletonFunc() blueprint.Singleton {
+	return &makeVarsSingleton{}
+}
+
+type makeVarsSingleton struct{}
+
+type makeVarsProvider struct {
+	pctx blueprint.PackageContext
+	call MakeVarsProvider
+}
+
+var makeVarsProviders []makeVarsProvider
+
+type makeVarsContext struct {
+	config Config
+	ctx    blueprint.SingletonContext
+	pctx   blueprint.PackageContext
+	vars   []makeVarsVariable
+}
+
+var _ MakeVarsContext = &makeVarsContext{}
+
+type makeVarsVariable struct {
+	name   string
+	value  string
+	sort   bool
+	strict bool
+}
+
+func (s *makeVarsSingleton) GenerateBuildActions(ctx blueprint.SingletonContext) {
+	config := ctx.Config().(Config)
+
+	if !config.EmbeddedInMake() {
+		return
+	}
+
+	outFile := PathForOutput(ctx, "make_vars"+proptools.String(config.ProductVariables.Make_suffix)+".mk").String()
+
+	if ctx.Failed() {
+		return
+	}
+
+	vars := []makeVarsVariable{}
+	for _, provider := range makeVarsProviders {
+		mctx := &makeVarsContext{
+			config: config,
+			ctx:    ctx,
+			pctx:   provider.pctx,
+		}
+
+		provider.call(mctx)
+
+		vars = append(vars, mctx.vars...)
+	}
+
+	if ctx.Failed() {
+		return
+	}
+
+	outBytes := s.writeVars(vars)
+
+	if _, err := os.Stat(outFile); err == nil {
+		if data, err := ioutil.ReadFile(outFile); err == nil {
+			if bytes.Equal(data, outBytes) {
+				return
+			}
+		}
+	}
+
+	if err := ioutil.WriteFile(outFile, outBytes, 0666); err != nil {
+		ctx.Errorf(err.Error())
+	}
+}
+
+func (s *makeVarsSingleton) writeVars(vars []makeVarsVariable) []byte {
+	buf := &bytes.Buffer{}
+
+	fmt.Fprintln(buf, `# Autogenerated file
+
+# Compares SOONG_$(1) against $(1), and warns if they are not equal.
+#
+# If the original variable is empty, then just set it to the SOONG_ version.
+#
+# $(1): Name of the variable to check
+# $(2): If not-empty, sort the values before comparing
+# $(3): Extra snippet to run if it does not match
+define soong-compare-var
+ifneq ($$($(1)),)
+  my_val_make := $(if $(2),$$(sort $$($(1))),$$($(1)))
+  my_val_soong := $(if $(2),$$(sort $$(SOONG_$(1))),$$(SOONG_$(1)))
+  ifneq ($$(my_val_make),$$(my_val_soong))
+    $$(warning $(1) does not match between Make and Soong:)
+    $(if $(2),$$(warning Make  adds: $$(filter-out $$(my_val_soong),$$(my_val_make))),$$(warning Make : $$(my_val_make)))
+    $(if $(2),$$(warning Soong adds: $$(filter-out $$(my_val_make),$$(my_val_soong))),$$(warning Soong: $$(my_val_soong)))
+    $(3)
+  endif
+  my_val_make :=
+  my_val_soong :=
+else
+  $(1) := $$(SOONG_$(1))
+endif
+endef
+
+my_check_failed := false
+
+`)
+
+	// Write all the strict checks out first so that if one of them errors,
+	// we get all of the strict errors printed, but not the non-strict
+	// warnings.
+	for _, v := range vars {
+		if !v.strict {
+			continue
+		}
+
+		sort := ""
+		if v.sort {
+			sort = "true"
+		}
+
+		fmt.Fprintf(buf, "SOONG_%s := %s\n", v.name, v.value)
+		fmt.Fprintf(buf, "$(eval $(call soong-compare-var,%s,%s,my_check_failed := true))\n\n", v.name, sort)
+	}
+
+	fmt.Fprintln(buf, `
+ifneq ($(my_check_failed),false)
+  $(error Soong variable check failed)
+endif
+my_check_failed :=
+
+
+`)
+
+	for _, v := range vars {
+		if v.strict {
+			continue
+		}
+
+		sort := ""
+		if v.sort {
+			sort = "true"
+		}
+
+		fmt.Fprintf(buf, "SOONG_%s := %s\n", v.name, v.value)
+		fmt.Fprintf(buf, "$(eval $(call soong-compare-var,%s,%s))\n\n", v.name, sort)
+	}
+
+	fmt.Fprintln(buf, "\nsoong-compare-var :=")
+
+	return buf.Bytes()
+}
+
+func (c *makeVarsContext) Config() Config {
+	return c.config
+}
+
+func (c *makeVarsContext) addVariable(name, ninjaStr string, strict, sort bool) {
+	value, err := c.ctx.Eval(c.pctx, ninjaStr)
+	if err != nil {
+		c.ctx.Errorf(err.Error())
+	}
+	c.vars = append(c.vars, makeVarsVariable{
+		name:   name,
+		value:  value,
+		strict: strict,
+		sort:   sort,
+	})
+}
+
+func (c *makeVarsContext) Strict(name, ninjaStr string) {
+	c.addVariable(name, ninjaStr, true, false)
+}
+func (c *makeVarsContext) StrictSorted(name, ninjaStr string) {
+	c.addVariable(name, ninjaStr, true, true)
+}
+
+func (c *makeVarsContext) Check(name, ninjaStr string) {
+	c.addVariable(name, ninjaStr, false, false)
+}
+func (c *makeVarsContext) CheckSorted(name, ninjaStr string) {
+	c.addVariable(name, ninjaStr, false, true)
+}