[SR-648] ELF static binary fixes

- Revert the use of SWIFT_RUNTIME_EXPORT in ImageInspectionELF.cpp and
  fix the unittests by explicitly adding the file to the list

- Revert the change of section data names

Author: spevans

stdlib/public/runtime/ImageInspectionELF.cpp

@@ -19,7 +19,6 @@
 #if defined(__ELF__) || defined(__ANDROID__)
 
 #include "ImageInspection.h"
-#include "../SwiftShims/Visibility.h"
 #include <elf.h>
 #include <link.h>
 #include <dlfcn.h>
@@ -30,11 +29,11 @@ using namespace swift;
 /// The symbol name in the image that identifies the beginning of the
 /// protocol conformances table.
 static const char ProtocolConformancesSymbol[] =
-  "__swift2_protocol_conformances_start";
+  ".swift2_protocol_conformances_start";
 /// The symbol name in the image that identifies the beginning of the
 /// type metadata record table.
 static const char TypeMetadataRecordsSymbol[] =
-  "__swift2_type_metadata_start";
+  ".swift2_type_metadata_start";
 
 /// Context arguments passed down from dl_iterate_phdr to its callback.
 struct InspectArgs {
@@ -79,7 +78,6 @@ static int iteratePHDRCallback(struct dl_phdr_info *info,
   return 0;
 }
 
-SWIFT_RUNTIME_EXPORT
 void swift::initializeProtocolConformanceLookup() {
   // Search the loaded dls. This only searches the already
   // loaded ones.
@@ -92,7 +90,6 @@ void swift::initializeProtocolConformanceLookup() {
   dl_iterate_phdr(iteratePHDRCallback, &ProtocolConformanceArgs);
 }
 
-SWIFT_RUNTIME_EXPORT
 void swift::initializeTypeMetadataRecordLookup() {
   InspectArgs TypeMetadataRecordArgs = {
     TypeMetadataRecordsSymbol,
@@ -101,7 +98,6 @@ void swift::initializeTypeMetadataRecordLookup() {
   dl_iterate_phdr(iteratePHDRCallback, &TypeMetadataRecordArgs);
 }
 
-SWIFT_RUNTIME_EXPORT
 int swift::lookupSymbol(const void *address, SymbolInfo *info) {
   Dl_info dlinfo;
   if (dladdr(address, &dlinfo) == 0) {

stdlib/public/runtime/ImageInspectionStatic.cpp

@@ -15,32 +15,42 @@
 //===----------------------------------------------------------------------===//
 
 #include "ImageInspection.h"
+#include <cstring>
 
 // Currently only tested on linux but should work for any ELF platform
 #if defined(__ELF__) && defined(__linux__)
 
-// These are defined in swift_sections.S
-// Used in swift_sections.S to mark the start of a section
+// These are defined in swift_sections.S to mark the start of a section with the
+// length of the data followed immediately by the section data
+struct alignas(uint64_t) Section;
+extern const Section protocolConformancesStart asm(".swift2_protocol_conformances_start");
+extern const Section typeMetadataStart asm(".swift2_type_metadata_start");
+
 struct SectionInfo {
   uint64_t size;
-  const uint8_t data[0];
+  const char *data;
 };
-extern const SectionInfo __swift2_protocol_conformances_start;
-extern const SectionInfo __swift2_type_metadata_start;
 
+static SectionInfo
+getSectionInfo(const Section *section) {
+  SectionInfo info;
+  memcpy(&info.size, section, sizeof(uint64_t));
+  info.data = reinterpret_cast<const char *>(section) + sizeof(uint64_t);
+  return info;
+}
 
 void
 swift::initializeProtocolConformanceLookup() {
-  addImageProtocolConformanceBlockCallback(
-    __swift2_protocol_conformances_start.data,
-    __swift2_protocol_conformances_start.size);
+  auto protocolConformances = getSectionInfo(&protocolConformancesStart);
+  addImageProtocolConformanceBlockCallback(protocolConformances.data,
+                                           protocolConformances.size);
 }
 
 void
 swift::initializeTypeMetadataRecordLookup() {
-  addImageTypeMetadataRecordBlockCallback(
-    __swift2_type_metadata_start.data,
-    __swift2_type_metadata_start.size);
+  auto typeMetadata = getSectionInfo(&typeMetadataStart);
+  addImageTypeMetadataRecordBlockCallback(typeMetadata.data,
+                                          typeMetadata.size);
 }
 
 // This is called from Errors.cpp when dumping a stack trace entry.

stdlib/public/runtime/swift_sections.S

@@ -31,14 +31,14 @@
     .p2align 3
 
 #if defined(SWIFT_BEGIN)
-    .globl __\()\name\()_start
-    .protected __\()\name\()_start
-__\()\name\()_start:
+    .globl .\()\name\()_start
+    .protected .\()\name\()_start
+.\()\name\()_start:
 #if defined(__BIG_ENDIAN__)
     .long 0
-    .long .\()\name\()_end - __\()\name\()_start - 8
+    .long .\()\name\()_end - .\()\name\()_start - 8
 #else
-    .long .\()\name\()_end - __\()\name\()_start - 8
+    .long .\()\name\()_end - .\()\name\()_start - 8
     .long 0
 #endif
 #endif

unittests/runtime/CMakeLists.txt

@@ -1,6 +1,11 @@
 if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
    ("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "${SWIFT_PRIMARY_VARIANT_ARCH}"))
 
+  if(SWIFT_BUILD_STATIC_STDLIB AND "${SWIFT_HOST_VARIANT_SDK}" STREQUAL "LINUX")
+    set(swift_runtime_test_extra_sources
+      "${CMAKE_CURRENT_SOURCE_DIR}/../../stdlib/public/runtime/ImageInspectionELF.cpp")
+  endif()
+
   add_subdirectory(LongTests)
 
   set(PLATFORM_SOURCES)
@@ -36,6 +41,7 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
     # from the swiftCore dylib, so we need to link to both the runtime archive
     # and the stdlib.
     $<TARGET_OBJECTS:swiftRuntime${SWIFT_PRIMARY_VARIANT_SUFFIX}>
+    ${swift_runtime_test_extra_sources}
     )
 
   # FIXME: cross-compile for all variants.

unittests/runtime/LongTests/CMakeLists.txt

@@ -32,6 +32,7 @@ if(("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "${SWIFT_PRIMARY_VARIANT_SDK}") AND
     # from the swiftCore dylib, so we need to link to both the runtime archive
     # and the stdlib.
     $<TARGET_OBJECTS:swiftRuntime${SWIFT_PRIMARY_VARIANT_SUFFIX}>
+    ${swift_runtime_test_extra_sources}
     )
 
   # FIXME: cross-compile for all variants.