Runtimes: ensure that we strongly resolve all symbols on Linux

Ensure that there are no undefined symbols at link time to validate that
we fully specified dependencies. This is the default behaviour on
Windows, but ELF targets will simply make any undefined symbols weakly
defined and rely on load time symbolic resolution.

Author: compnerd

Runtimes/Core/CMakeLists.txt

@@ -182,6 +182,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 add_compile_options(
   $<$<COMPILE_LANGUAGE:Swift>:-explicit-module-build>

Runtimes/Overlay/CMakeLists.txt

@@ -94,6 +94,8 @@ include(ExperimentalFeatures)
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 include(ExperimentalFeatures)
 

Runtimes/Supplemental/Differentiation/CMakeLists.txt

@@ -88,6 +88,8 @@ add_compile_options(
 # FIXME(#83444) - enable this once we fix DLL storage for
 # `_fatalErrorForwardModeDifferentiationDisabled`
 # add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 if(SwiftDifferentiation_ENABLE_VECTOR_TYPES)
   gyb_expand(SIMDDifferentiation.swift.gyb SIMDDifferentiation.swift)

Runtimes/Supplemental/Distributed/CMakeLists.txt

@@ -98,6 +98,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 add_library(swiftDistributed
   DistributedActor.cpp

Runtimes/Supplemental/Observation/CMakeLists.txt

@@ -83,6 +83,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 add_library(swiftObservation
   Sources/Observation/Locking.swift

Runtimes/Supplemental/StringProcessing/CMakeLists.txt

@@ -65,6 +65,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 add_subdirectory(_RegexParser)
 add_subdirectory(_StringProcessing)

Runtimes/Supplemental/Synchronization/CMakeLists.txt

@@ -101,6 +101,8 @@ add_compile_options(
 # frontned and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 gyb_expand(Atomics/AtomicIntegers.swift.gyb Atomics/AtomicIntegers.swift)
 gyb_expand(Atomics/AtomicStorage.swift.gyb Atomics/AtomicStorage.swift)

Runtimes/Supplemental/Volatile/CMakeLists.txt

@@ -77,6 +77,8 @@ add_compile_options(
 # frontend and `clang-cl` (and `clang`) currently do not support `/WX:nnnn`. As
 # a compromise, treat all linker warnings as errors.
 add_link_options($<$<PLATFORM_ID:Windows>:LINKER:/WX>)
+# Ensure all symbols are fully resolved on Linux
+add_link_options($<$<PLATFORM_ID:Linux>:LINKER:-z,defs>)
 
 add_library(swift_Volatile
   Volatile.swift)