compiler: move ApplyFunctionSections to transform package

builder/build.go

@@ -53,7 +53,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 	}
 
 	if config.GOOS() != "darwin" {
-		c.ApplyFunctionSections() // -ffunction-sections
+		transform.ApplyFunctionSections(c.Module()) // -ffunction-sections
 	}
 
 	// Browsers cannot handle external functions that have type i64 because it

compiler/compiler.go

@@ -2585,19 +2585,6 @@ func (c *Compiler) Verify() error {
 	return llvm.VerifyModule(c.mod, llvm.PrintMessageAction)
 }
 
-func (c *Compiler) ApplyFunctionSections() {
-	// Put every function in a separate section. This makes it possible for the
-	// linker to remove dead code (-ffunction-sections).
-	llvmFn := c.mod.FirstFunction()
-	for !llvmFn.IsNil() {
-		if !llvmFn.IsDeclaration() {
-			name := llvmFn.Name()
-			llvmFn.SetSection(".text." + name)
-		}
-		llvmFn = llvm.NextFunction(llvmFn)
-	}
-}
-
 // Turn all global constants into global variables. This works around a
 // limitation on Harvard architectures (e.g. AVR), where constant and
 // non-constant pointers point to a different address space.

transform/globals.go

@@ -0,0 +1,20 @@
+package transform
+
+import "tinygo.org/x/go-llvm"
+
+// This file implements small transformations on globals (functions and global
+// variables) for specific ABIs/architectures.
+
+// ApplyFunctionSections puts every function in a separate section. This makes
+// it possible for the linker to remove dead code. It is the equivalent of
+// passing -ffunction-sections to a C compiler.
+func ApplyFunctionSections(mod llvm.Module) {
+	llvmFn := mod.FirstFunction()
+	for !llvmFn.IsNil() {
+		if !llvmFn.IsDeclaration() {
+			name := llvmFn.Name()
+			llvmFn.SetSection(".text." + name)
+		}
+		llvmFn = llvm.NextFunction(llvmFn)
+	}
+}

transform/globals_test.go

@@ -0,0 +1,14 @@
+package transform
+
+import (
+	"testing"
+
+	"tinygo.org/x/go-llvm"
+)
+
+func TestApplyFunctionSections(t *testing.T) {
+	t.Parallel()
+	testTransform(t, "testdata/globals-function-sections", func(mod llvm.Module) {
+		ApplyFunctionSections(mod)
+	})
+}

transform/testdata/globals-function-sections.ll

@@ -0,0 +1,8 @@
+target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv7em-none-eabi"
+
+declare void @foo()
+
+define void @bar() {
+  ret void
+}

transform/testdata/globals-function-sections.out.ll

@@ -0,0 +1,8 @@
+target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv7em-none-eabi"
+
+declare void @foo()
+
+define void @bar() section ".text.bar" {
+  ret void
+}