Support more configurability in GN toolchains

tools/gn/toolchain.cc

Index: tools/gn/toolchain.cc
diff --git a/tools/gn/toolchain.cc b/tools/gn/toolchain.cc
index eee458a974cebf077fb3bc5589d65b7489a194bc..1171c593b6978a805b748c938741b6ba92459b91 100644
--- a/tools/gn/toolchain.cc
+++ b/tools/gn/toolchain.cc
@@ -4,7 +4,10 @@
 
 #include "tools/gn/toolchain.h"
 
+#include <string.h>
+
 #include "base/logging.h"
+#include "tools/gn/target.h"
 #include "tools/gn/value.h"
 
 const char* Toolchain::kToolCc = "cc";
@@ -19,14 +22,9 @@ const char* Toolchain::kToolLink = "link";
 const char* Toolchain::kToolStamp = "stamp";
 const char* Toolchain::kToolCopy = "copy";
 
-Toolchain::Tool::Tool() {
-}
-
-Toolchain::Tool::~Tool() {
-}
-
 Toolchain::Toolchain(const Settings* settings, const Label& label)
-    : Item(settings, label) {
+    : Item(settings, label),
+      setup_complete_(false) {
 }
 
 Toolchain::~Toolchain() {
@@ -76,12 +74,84 @@ std::string Toolchain::ToolTypeToName(ToolType type) {
   }
 }
 
-const Toolchain::Tool& Toolchain::GetTool(ToolType type) const {
+const Tool* Toolchain::GetTool(ToolType type) const {
   DCHECK(type != TYPE_NONE);
-  return tools_[static_cast<size_t>(type)];
+  return tools_[static_cast<size_t>(type)].get();
 }
 
-void Toolchain::SetTool(ToolType type, const Tool& t) {
+void Toolchain::SetTool(ToolType type, scoped_ptr<Tool> t) {
   DCHECK(type != TYPE_NONE);
-  tools_[static_cast<size_t>(type)] = t;
+  DCHECK(!tools_[type].get());
+  t->SetComplete();
+  tools_[type] = t.Pass();
+}
+
+void Toolchain::ToolchainSetupComplete() {
+  // Collect required bits from all tools.
+  for (size_t i = 0; i < TYPE_NUMTYPES; i++) {
+    if (tools_[i])
+      substitution_bits_.MergeFrom(tools_[i]->substitution_bits());
+  }
+
+  setup_complete_ = true;
+}
+
+// static
+Toolchain::ToolType Toolchain::GetToolTypeForSourceType(SourceFileType type) {
+  switch (type) {
+    case SOURCE_C:
+      return TYPE_CC;
+    case SOURCE_CC:
+      return TYPE_CXX;
+    case SOURCE_M:
+      return TYPE_OBJC;
+    case SOURCE_MM:
+      return TYPE_OBJCXX;
+    case SOURCE_ASM:
+    case SOURCE_S:
+      return TYPE_ASM;
+    case SOURCE_RC:
+      return TYPE_RC;
+    case SOURCE_UNKNOWN:
+    case SOURCE_H:
+    case SOURCE_O:
+      return TYPE_NONE;
+    default:
+      NOTREACHED();
+      return TYPE_NONE;
+  }
+}
+
+const Tool* Toolchain::GetToolForSourceType(SourceFileType type) {
+  return tools_[GetToolTypeForSourceType(type)].get();
+}
+
+// static
+Toolchain::ToolType Toolchain::GetToolTypeForTargetFinalOutput(
+    const Target* target) {
+  // The contents of this list might be suprising (i.e. stamp tool for copy
+  // rules). See the header for why.
+  switch (target->output_type()) {
+    case Target::GROUP:
+      return TYPE_STAMP;
+    case Target::EXECUTABLE:
+      return Toolchain::TYPE_LINK;
+    case Target::SHARED_LIBRARY:
+      return Toolchain::TYPE_SOLINK;
+    case Target::STATIC_LIBRARY:
+      return Toolchain::TYPE_ALINK;
+    case Target::SOURCE_SET:
+      return TYPE_STAMP;
+    case Target::COPY_FILES:
+    case Target::ACTION:
+    case Target::ACTION_FOREACH:
+      return TYPE_STAMP;
+    default:
+      NOTREACHED();
+      return Toolchain::TYPE_NONE;
+  }
+}
+
+const Tool* Toolchain::GetToolForTargetFinalOutput(const Target* target) const {
+  return tools_[GetToolTypeForTargetFinalOutput(target)].get();
 }