From 5bbd41e9fb4d02f97ef7af3435d08c367f8f5e0c Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Fri, 27 Apr 2018 01:27:33 +0200
Subject: [PATCH] compiler: Implement -ffunction-sections work

---
 Makefile |  2 +-
 tgo.go   | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index da489c44..332e924f 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ TARGET ?= unix
 
 ifeq ($(TARGET),pca10040)
 GCC = arm-none-eabi-gcc
-LD = arm-none-eabi-ld -T arm.ld
+LD = arm-none-eabi-ld -T arm.ld --gc-sections
 SIZE = arm-none-eabi-size
 OBJCOPY = arm-none-eabi-objcopy
 LLFLAGS += -target armv7m-none-eabi
diff --git a/tgo.go b/tgo.go
index 4bff69ac..e596387c 100644
--- a/tgo.go
+++ b/tgo.go
@@ -1082,6 +1082,16 @@ func (c *Compiler) LinkModule(mod llvm.Module) error {
 	return llvm.LinkModules(c.mod, mod)
 }
 
+func (c *Compiler) ApplyFunctionSections() {
+	llvmFn := c.mod.FirstFunction()
+	for !llvmFn.IsNil() {
+		if !llvmFn.IsDeclaration() {
+			llvmFn.SetSection(".text." + llvmFn.Name())
+		}
+		llvmFn = llvm.NextFunction(llvmFn)
+	}
+}
+
 func (c *Compiler) Optimize(optLevel, sizeLevel int) {
 	builder := llvm.NewPassManagerBuilder()
 	defer builder.Dispose()
@@ -1159,6 +1169,8 @@ func Compile(pkgName, runtimePath, outpath, target string, printIR bool) error {
 		return err
 	}
 
+	c.ApplyFunctionSections() // -ffunction-sections
+
 	if err := c.Verify(); err != nil {
 		return err
 	}