GH-35596: [C++][CI] Improve compilation caching with PCG (#35597)

### Rationale for this change The PCG headers use the `__DATE__` and `__TIME__` macros, which makes builds non-deterministic: imneme/pcg-cpp#59 Deterministic builds are useful for a number of reasons. One is security audits of binary artifacts, another (that directly affects us) is making compilation caching as efficient as possible. Preprocessor-based compilation caching breaks when time-dependent macros are used. ### What changes are included in this PR? Remove the `struct static_arbitrary_seed` construct from PCG. Also, enable a gcc/clang warning that detects the use of non-deterministic preprocessor macros. ### Are these changes tested? Yes, by the additional warning (which is turned into an error in "checkin" warnings mode). ### Are there any user-facing changes? No. * Closes: #35596 Authored-by: Antoine Pitrou <[email protected]> Signed-off-by: Antoine Pitrou <[email protected]>
apache · May 16, 2023 · f6e4479 · f6e4479
1 parent 8be70c1
commit f6e4479
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Showing 3 changed files with 4 additions and 21 deletions.
diff --git a/cpp/cmake_modules/SetupCxxFlags.cmake b/cpp/cmake_modules/SetupCxxFlags.cmake
@@ -311,11 +311,13 @@ if("${BUILD_WARNING_LEVEL}" STREQUAL "CHECKIN")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wno-unused-parameter")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wno-constant-logical-operand")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wno-return-stack-address")
+    set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wdate-time")
   elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wall")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wno-conversion")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wno-sign-conversion")
     set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wunused-result")
+    set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -Wdate-time")
   elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
     if(WIN32)
       set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} /Wall")

diff --git a/cpp/src/arrow/vendored/pcg/README.md b/cpp/src/arrow/vendored/pcg/README.md
@@ -24,3 +24,5 @@ Sources are taken from git changeset ffd522e7188bef30a00c74dc7eb9de5faff90092
 
 Changes:
 - enclosed in `arrow_vendored` namespace
+- remove `struct arbitrary_seed` definition because of https://github.com/apache/arrow/issues/35596
+
diff --git a/cpp/src/arrow/vendored/pcg/pcg_extras.hpp b/cpp/src/arrow/vendored/pcg/pcg_extras.hpp
@@ -612,27 +612,6 @@ class seed_seq_from {
     }
 };
 
-/*
- * Sometimes you might want a distinct seed based on when the program
- * was compiled.  That way, a particular instance of the program will
- * behave the same way, but when recompiled it'll produce a different
- * value.
- */
-
-template <typename IntType>
-struct static_arbitrary_seed {
-private:
-    static constexpr IntType fnv(IntType hash, const char* pos) {
-        return *pos == '\0'
-             ? hash
-             : fnv((hash * IntType(16777619U)) ^ *pos, (pos+1));
-    }
-
-public:
-    static constexpr IntType value = fnv(IntType(2166136261U ^ sizeof(IntType)),
-                        __DATE__ __TIME__ __FILE__);
-};
-
 // Sometimes, when debugging or testing, it's handy to be able print the name
 // of a (in human-readable form).  This code allows the idiom:
 //
Original file line number	Diff line number	Diff line change
Expand Up		@@ -24,3 +24,5 @@ Sources are taken from git changeset ffd522e7188bef30a00c74dc7eb9de5faff90092

		Changes:
		- enclosed in `arrow_vendored` namespace
		- remove `struct arbitrary_seed` definition because of https://github.com/apache/arrow/issues/35596