user/glslang: spirv-remap: Cross-endian support

Reported upstream at https://github.com/KhronosGroup/glslang/issues/3799;
I'm not happy with the patch, and I feel like it can be better, but it
works and it unblocks Vulkan for beta6.

1 files changed, 46 insertions, 0 deletions

diff --git a/user/glslang/remap-endian.patch b/user/glslang/remap-endian.patch
new file mode 100644
index 000000000..4c1fc78ff
--- /dev/null
+++ b/user/glslang/remap-endian.patch
@@ -0,0 +1,46 @@
+Issue: https://github.com/KhronosGroup/glslang/issues/3799
+
+--- glslang-14.3.0/StandAlone/spirv-remap.cpp.old	2024-06-25 17:42:43.000000000 -0500
++++ glslang-14.3.0/StandAlone/spirv-remap.cpp	2024-11-22 15:27:02.655869572 -0600
+@@ -38,6 +38,7 @@
+ #include <cstring>
+ #include <stdexcept>
+ #include <filesystem>
++#include <byteswap.h>
+ 
+ //
+ // Include remapper
+@@ -48,6 +49,8 @@
+ 
+     typedef unsigned int SpvWord;
+ 
++    static const SpvWord MagicNumber = 0x07230203;
++
+     // Poor man's basename: given a complete path, return file portion.
+     // E.g:
+     //      Linux:  /foo/bar/test  -> test
+@@ -82,6 +85,7 @@
+     void read(std::vector<SpvWord>& spv, const std::string& inFilename, int verbosity)
+     {
+         std::ifstream fp;
++        bool isNativeEndian = true;
+ 
+         if (verbosity > 0)
+             logHandler(std::string("  reading: ") + inFilename);
+@@ -97,11 +101,16 @@
+         spv.reserve(size_t(fp.tellg()) / sizeof(SpvWord));
+         fp.seekg(0, fp.beg);
+ 
++        char begin = fp.peek();
++        char native_begin = reinterpret_cast<const char*>(&MagicNumber)[0];
++        if (begin != native_begin) isNativeEndian = false;
++
+         while (!fp.eof()) {
+             SpvWord inWord;
+             fp.read((char *)&inWord, sizeof(inWord));
+ 
+             if (!fp.eof()) {
++                if (!isNativeEndian) inWord = __bswap_32(inWord);
+                 spv.push_back(inWord);
+                 if (fp.fail())
+                     errHandler(std::string("error reading file: ") + inFilename);