split Symbolizer and SignalHandler into their own targets

Summary:
In the interest of using SignalHandler on macOS, which does not use
ELF, break some dependencies and split the targets.

Reviewed By: yfeldblum, luciang

Differential Revision: D22883896

fbshipit-source-id: e576b6e1684522fc1665c864780faea882d0263a

folly/detail/SingletonStackTrace.cpp

@@ -19,6 +19,7 @@
 #include <folly/portability/Config.h>
 
 #if FOLLY_USE_SYMBOLIZER
+#include <folly/experimental/symbolizer/ElfCache.h> // @manual
 #include <folly/experimental/symbolizer/Symbolizer.h> // @manual
 #endif
 

folly/experimental/symbolizer/SignalHandler.cpp

@@ -32,7 +32,6 @@
 
 #include <folly/Conv.h>
 #include <folly/ScopeGuard.h>
-#include <folly/experimental/symbolizer/ElfCache.h>
 #include <folly/experimental/symbolizer/Symbolizer.h>
 #include <folly/portability/SysSyscall.h>
 #include <folly/portability/Unistd.h>

folly/experimental/symbolizer/SignalHandler.h

@@ -17,7 +17,6 @@
 #pragma once
 
 #include <bitset>
-#include <functional>
 
 namespace folly {
 namespace symbolizer {

folly/experimental/symbolizer/SymbolizedFrame.h

@@ -16,24 +16,24 @@
 
 #pragma once
 
-#include <array>
 #include <cstdint>
 #include <memory>
 #include <string>
 
 #include <folly/Range.h>
-#include <folly/experimental/symbolizer/Elf.h>
 
 namespace folly {
 namespace symbolizer {
 
+class ElfFile;
+
 /**
- * Represent a file path a s collection of three parts (base directory,
+ * Represent a file path as a collection of three parts (base directory,
  * subdirectory, and file).
  */
 class Path {
  public:
-  Path() {}
+  Path() = default;
 
   Path(
       folly::StringPiece baseDir,
@@ -121,7 +121,7 @@ struct SymbolizedFrame {
 
 template <size_t N>
 struct FrameArray {
-  FrameArray() {}
+  FrameArray() = default;
 
   size_t frameCount = 0;
   uintptr_t addresses[N];

folly/experimental/symbolizer/Symbolizer.cpp

@@ -36,6 +36,7 @@
 #include <folly/String.h>
 #include <folly/experimental/symbolizer/Dwarf.h>
 #include <folly/experimental/symbolizer/Elf.h>
+#include <folly/experimental/symbolizer/ElfCache.h>
 #include <folly/experimental/symbolizer/LineReader.h>
 #include <folly/lang/SafeAssert.h>
 #include <folly/portability/SysMman.h>

folly/experimental/symbolizer/Symbolizer.h

@@ -28,8 +28,6 @@
 #include <folly/Synchronized.h>
 #include <folly/container/EvictingCacheMap.h>
 #include <folly/experimental/symbolizer/Dwarf.h>
-#include <folly/experimental/symbolizer/Elf.h>
-#include <folly/experimental/symbolizer/ElfCache.h>
 #include <folly/experimental/symbolizer/StackTrace.h>
 #include <folly/experimental/symbolizer/SymbolizedFrame.h>
 #include <folly/io/IOBuf.h>
@@ -37,6 +35,8 @@
 namespace folly {
 namespace symbolizer {
 
+class ElfCacheBase;
+class ElfCache;
 class Symbolizer;
 
 /**

folly/experimental/symbolizer/test/SmallSigAltStackCrash.cpp

@@ -15,6 +15,7 @@
  */
 
 #include <signal.h>
+#include <array>
 
 #include <folly/experimental/symbolizer/SignalHandler.h>
 

folly/experimental/symbolizer/test/SymbolizerTest.cpp

@@ -22,6 +22,7 @@
 #include <folly/Demangle.h>
 #include <folly/Range.h>
 #include <folly/String.h>
+#include <folly/experimental/symbolizer/ElfCache.h>
 #include <folly/experimental/symbolizer/SymbolizedFrame.h>
 #include <folly/experimental/symbolizer/test/SymbolizerTestUtils.h>
 #include <folly/portability/GTest.h>