diff options
Diffstat (limited to 'builder')
| -rw-r--r-- | builder/build.go | 138 |
1 files changed, 118 insertions, 20 deletions
diff --git a/builder/build.go b/builder/build.go index 319474619..f16916ceb 100644 --- a/builder/build.go +++ b/builder/build.go @@ -52,16 +52,17 @@ type BuildResult struct { // key, avoiding the need for recompiling all dependencies when only the // implementation of an imported package changes. type packageAction struct { - ImportPath string - CompilerVersion int // compiler.Version - InterpVersion int // interp.Version - LLVMVersion string - Config *compiler.Config - CFlags []string - FileHashes map[string]string // hash of every file that's part of the package - Imports map[string]string // map from imported package to action ID hash - OptLevel int // LLVM optimization level (0-3) - SizeLevel int // LLVM optimization for size level (0-2) + ImportPath string + CompilerVersion int // compiler.Version + InterpVersion int // interp.Version + LLVMVersion string + Config *compiler.Config + CFlags []string + FileHashes map[string]string // hash of every file that's part of the package + Imports map[string]string // map from imported package to action ID hash + OptLevel int // LLVM optimization level (0-3) + SizeLevel int // LLVM optimization for size level (0-2) + UndefinedGlobals []string // globals that are left as external globals (no initializer) } // Build performs a single package to executable Go build. It takes in a package @@ -133,19 +134,26 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(Buil for _, pkg := range lprogram.Sorted() { pkg := pkg // necessary to avoid a race condition + var undefinedGlobals []string + for name := range config.Options.GlobalValues[pkg.Pkg.Path()] { + undefinedGlobals = append(undefinedGlobals, name) + } + sort.Strings(undefinedGlobals) + // Create a cache key: a hash from the action ID below that contains all // the parameters for the build. actionID := packageAction{ - ImportPath: pkg.ImportPath, - CompilerVersion: compiler.Version, - InterpVersion: interp.Version, - LLVMVersion: llvm.Version, - Config: compilerConfig, - CFlags: pkg.CFlags, - FileHashes: make(map[string]string, len(pkg.FileHashes)), - Imports: make(map[string]string, len(pkg.Pkg.Imports())), - OptLevel: optLevel, - SizeLevel: sizeLevel, + ImportPath: pkg.ImportPath, + CompilerVersion: compiler.Version, + InterpVersion: interp.Version, + LLVMVersion: llvm.Version, + Config: compilerConfig, + CFlags: pkg.CFlags, + FileHashes: make(map[string]string, len(pkg.FileHashes)), + Imports: make(map[string]string, len(pkg.Pkg.Imports())), + OptLevel: optLevel, + SizeLevel: sizeLevel, + UndefinedGlobals: undefinedGlobals, } for filePath, hash := range pkg.FileHashes { actionID.FileHashes[filePath] = hex.EncodeToString(hash) @@ -196,6 +204,25 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(Buil return errors.New("verification error after compiling package " + pkg.ImportPath) } + // Erase all globals that are part of the undefinedGlobals list. + // This list comes from the -ldflags="-X pkg.foo=val" option. + // Instead of setting the value directly in the AST (which would + // mean the value, which may be a secret, is stored in the build + // cache), the global itself is left external (undefined) and is + // only set at the end of the compilation. + for _, name := range undefinedGlobals { + globalName := pkg.Pkg.Path() + "." + name + global := mod.NamedGlobal(globalName) + if global.IsNil() { + return errors.New("global not found: " + globalName) + } + name := global.Name() + newGlobal := llvm.AddGlobal(mod, global.Type().ElementType(), name+".tmp") + global.ReplaceAllUsesWith(newGlobal) + global.EraseFromParentAsGlobal() + newGlobal.SetName(name) + } + // Try to interpret package initializers at compile time. // It may only be possible to do this partially, in which case // it is completed after all IR files are linked. @@ -640,6 +667,12 @@ func optimizeProgram(mod llvm.Module, config *compileopts.Config) error { transform.ApplyFunctionSections(mod) // -ffunction-sections } + // Insert values from -ldflags="-X ..." into the IR. + err = setGlobalValues(mod, config.Options.GlobalValues) + if err != nil { + return err + } + // Browsers cannot handle external functions that have type i64 because it // cannot be represented exactly in JavaScript (JS only has doubles). To // keep functions interoperable, pass int64 types as pointers to @@ -677,6 +710,71 @@ func optimizeProgram(mod llvm.Module, config *compileopts.Config) error { return nil } +// setGlobalValues sets the global values from the -ldflags="-X ..." compiler +// option in the given module. An error may be returned if the global is not of +// the expected type. +func setGlobalValues(mod llvm.Module, globals map[string]map[string]string) error { + var pkgPaths []string + for pkgPath := range globals { + pkgPaths = append(pkgPaths, pkgPath) + } + sort.Strings(pkgPaths) + for _, pkgPath := range pkgPaths { + pkg := globals[pkgPath] + var names []string + for name := range pkg { + names = append(names, name) + } + sort.Strings(names) + for _, name := range names { + value := pkg[name] + globalName := pkgPath + "." + name + global := mod.NamedGlobal(globalName) + if global.IsNil() || !global.Initializer().IsNil() { + // The global either does not exist (optimized away?) or has + // some value, in which case it has already been initialized at + // package init time. + continue + } + + // A strin is a {ptr, len} pair. We need these types to build the + // initializer. + initializerType := global.Type().ElementType() + if initializerType.TypeKind() != llvm.StructTypeKind || initializerType.StructName() == "" { + return fmt.Errorf("%s: not a string", globalName) + } + elementTypes := initializerType.StructElementTypes() + if len(elementTypes) != 2 { + return fmt.Errorf("%s: not a string", globalName) + } + + // Create a buffer for the string contents. + bufInitializer := mod.Context().ConstString(value, false) + buf := llvm.AddGlobal(mod, bufInitializer.Type(), ".string") + buf.SetInitializer(bufInitializer) + buf.SetAlignment(1) + buf.SetUnnamedAddr(true) + buf.SetLinkage(llvm.PrivateLinkage) + + // Create the string value, which is a {ptr, len} pair. + zero := llvm.ConstInt(mod.Context().Int32Type(), 0, false) + ptr := llvm.ConstGEP(buf, []llvm.Value{zero, zero}) + if ptr.Type() != elementTypes[0] { + return fmt.Errorf("%s: not a string", globalName) + } + length := llvm.ConstInt(elementTypes[1], uint64(len(value)), false) + initializer := llvm.ConstNamedStruct(initializerType, []llvm.Value{ + ptr, + length, + }) + + // Set the initializer. No initializer should be set at this point. + global.SetInitializer(initializer) + } + } + return nil +} + // functionStackSizes keeps stack size information about a single function // (usually a goroutine). type functionStackSize struct { |