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authorAyke van Laethem <[email protected]>2022-09-08 13:44:48 +0200
committerAyke van Laethem <[email protected]>2022-09-15 11:36:26 +0200
commit7e7814a0872c079d82d2f1837078e7eb5db06798 (patch)
tree6839ab169ce4966647f192491d62c5b75998f638
parent03d1c44265e1f628b2730b9c214db2390a745ee6 (diff)
downloadtinygo-7e7814a0872c079d82d2f1837078e7eb5db06798.tar.gz
tinygo-7e7814a0872c079d82d2f1837078e7eb5db06798.zip
wasm: do not export malloc, calloc, realloc, free
These functions were exported by accident, because the compiler had no way of saying these functions shouldn't be exported. This can be a big code size reduction for small programs. Before: $ tinygo build -o test.wasm -target=wasi -no-debug -scheduler=none ./testdata/alias.go && ls -l test.wasm -rwxrwxr-x 1 ayke ayke 2947 8 sep 13:47 test.wasm After: $ tinygo build -o test.wasm -target=wasi -no-debug -scheduler=none ./testdata/alias.go && ls -l test.wasm -rwxrwxr-x 1 ayke ayke 968 8 sep 13:47 test.wasm This is all because the GC isn't needed anymore. This commit also adds support for using //go:wasm-module to set the module name of an exported function (the default remains env).
-rw-r--r--compiler/compiler.go7
-rw-r--r--compiler/symbol.go32
-rw-r--r--compiler/testdata/pragma.ll4
-rw-r--r--src/runtime/arch_tinygowasm.go4
4 files changed, 21 insertions, 26 deletions
diff --git a/compiler/compiler.go b/compiler/compiler.go
index bbaf6432f..179a0928e 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -1059,11 +1059,12 @@ func (b *builder) createFunctionStart(intrinsic bool) {
if b.info.section != "" {
b.llvmFn.SetSection(b.info.section)
}
- if b.info.exported && strings.HasPrefix(b.Triple, "wasm") {
+ if b.info.exported && b.info.module != "" && strings.HasPrefix(b.Triple, "wasm") {
// Set the exported name. This is necessary for WebAssembly because
// otherwise the function is not exported.
- functionAttr := b.ctx.CreateStringAttribute("wasm-export-name", b.info.linkName)
- b.llvmFn.AddFunctionAttr(functionAttr)
+ b.llvmFn.AddFunctionAttr(b.ctx.CreateStringAttribute("wasm-export-name", b.info.linkName))
+ // Set the export module.
+ b.llvmFn.AddFunctionAttr(b.ctx.CreateStringAttribute("wasm-export-module", b.info.module))
}
// Some functions have a pragma controlling the inlining level.
diff --git a/compiler/symbol.go b/compiler/symbol.go
index c4ce6f21d..491b845c6 100644
--- a/compiler/symbol.go
+++ b/compiler/symbol.go
@@ -210,8 +210,9 @@ func (c *compilerContext) getFunction(fn *ssa.Function) llvm.Value {
// exported.
func (c *compilerContext) getFunctionInfo(f *ssa.Function) functionInfo {
info := functionInfo{
- // Pick the default linkName.
- linkName: f.RelString(nil),
+ module: "env",
+ importName: f.Name(),
+ linkName: f.RelString(nil), // pick the default linkName
}
// Check for //go: pragmas, which may change the link name (among others).
info.parsePragmas(f)
@@ -225,10 +226,6 @@ func (info *functionInfo) parsePragmas(f *ssa.Function) {
return
}
if decl, ok := f.Syntax().(*ast.FuncDecl); ok && decl.Doc != nil {
-
- // Our importName for a wasm module (if we are compiling to wasm), or llvm link name
- var importName string
-
for _, comment := range decl.Doc.List {
text := comment.Text
if strings.HasPrefix(text, "//export ") {
@@ -246,7 +243,8 @@ func (info *functionInfo) parsePragmas(f *ssa.Function) {
continue
}
- importName = parts[1]
+ info.importName = parts[1]
+ info.linkName = parts[1]
info.exported = true
case "//go:interrupt":
if hasUnsafeImport(f.Pkg.Pkg) {
@@ -254,10 +252,13 @@ func (info *functionInfo) parsePragmas(f *ssa.Function) {
}
case "//go:wasm-module":
// Alternative comment for setting the import module.
- if len(parts) != 2 {
- continue
+ if len(parts) == 1 {
+ // Function must not be exported outside of the WebAssembly
+ // module (but only be made available for linking).
+ info.module = ""
+ } else if len(parts) == 2 {
+ info.module = parts[1]
}
- info.module = parts[1]
case "//go:inline":
info.inline = inlineHint
case "//go:noinline":
@@ -297,17 +298,6 @@ func (info *functionInfo) parsePragmas(f *ssa.Function) {
}
}
}
-
- // Set the importName for our exported function if we have one
- if importName != "" {
- if info.module == "" {
- info.linkName = importName
- } else {
- // WebAssembly import
- info.importName = importName
- }
- }
-
}
}
diff --git a/compiler/testdata/pragma.ll b/compiler/testdata/pragma.ll
index b243602d3..403f4f4a0 100644
--- a/compiler/testdata/pragma.ll
+++ b/compiler/testdata/pragma.ll
@@ -62,7 +62,7 @@ declare void @main.undefinedFunctionNotInSection(i8*) #0
attributes #0 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
attributes #1 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
-attributes #2 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "wasm-export-name"="extern_func" "wasm-import-module"="env" "wasm-import-name"="extern_func" }
+attributes #2 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "wasm-export-module"="env" "wasm-export-name"="extern_func" "wasm-import-module"="env" "wasm-import-name"="extern_func" }
attributes #3 = { inlinehint nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
attributes #4 = { noinline nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
-attributes #5 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "wasm-export-name"="exportedFunctionInSection" "wasm-import-module"="env" "wasm-import-name"="exportedFunctionInSection" }
+attributes #5 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" "wasm-export-module"="env" "wasm-export-name"="exportedFunctionInSection" "wasm-import-module"="env" "wasm-import-name"="exportedFunctionInSection" }
diff --git a/src/runtime/arch_tinygowasm.go b/src/runtime/arch_tinygowasm.go
index 910858be6..eb5ba5b58 100644
--- a/src/runtime/arch_tinygowasm.go
+++ b/src/runtime/arch_tinygowasm.go
@@ -68,6 +68,7 @@ func growHeap() bool {
var allocs = make(map[uintptr][]byte)
//export malloc
+//go:wasm-module
func libc_malloc(size uintptr) unsafe.Pointer {
buf := make([]byte, size)
ptr := unsafe.Pointer(&buf[0])
@@ -76,6 +77,7 @@ func libc_malloc(size uintptr) unsafe.Pointer {
}
//export free
+//go:wasm-module
func libc_free(ptr unsafe.Pointer) {
if ptr == nil {
return
@@ -88,12 +90,14 @@ func libc_free(ptr unsafe.Pointer) {
}
//export calloc
+//go:wasm-module
func libc_calloc(nmemb, size uintptr) unsafe.Pointer {
// No difference between calloc and malloc.
return libc_malloc(nmemb * size)
}
//export realloc
+//go:wasm-module
func libc_realloc(oldPtr unsafe.Pointer, size uintptr) unsafe.Pointer {
// It's hard to optimize this to expand the current buffer with our GC, but
// it is theoretically possible. For now, just always allocate fresh.