[ubsan] Prevent miniz from performing unaligned load / stores (microsoft#7817)

damyanp · web-flow · commit 26251e3127aa · 2025-10-13T11:19:16.000-07:00
By default, miniz performs unaligned loads/stores in x86/x64 platforms.
This is undefined behavior in C, and so we explicitly disable it.


Fixes 98 ubsan / alignment errors when building check-all.
diff --git a/lib/DxilCompression/CMakeLists.txt b/lib/DxilCompression/CMakeLists.txt
@@ -9,5 +9,9 @@ add_llvm_library(LLVMDxilCompression
   ADDITIONAL_HEADER_DIRS
 )
 
+# By default, miniz performs unaligned loads/stores in x86/x64 platforms. This
+# is undefined behavior in C, and so we explicitly disable it.
+target_compile_definitions(LLVMDxilCompression PRIVATE MINIZ_USE_UNALIGNED_LOADS_AND_STORES=0)
+
 add_dependencies(LLVMDxilCompression intrinsics_gen)
 

Original file line number	Diff line number	Diff line change
`@@ -9,5 +9,9 @@ add_llvm_library(LLVMDxilCompression`
`9`	`9`	`ADDITIONAL_HEADER_DIRS`
`10`	`10`	`)`
`11`	`11`
	`12`	`+# By default, miniz performs unaligned loads/stores in x86/x64 platforms. This`
	`13`	`+# is undefined behavior in C, and so we explicitly disable it.`
	`14`	`+target_compile_definitions(LLVMDxilCompression PRIVATE MINIZ_USE_UNALIGNED_LOADS_AND_STORES=0)`
	`15`	`+`
`12`	`16`	`add_dependencies(LLVMDxilCompression intrinsics_gen)`
`13`	`17`