Merge pull request #14018 from glebm/fix-ubsan-warning-x64-emitter

x64Emitter: Fix unaligned store UBSAN errors
hrydgard · Jan 30, 2021 · 53b249f · 53b249f
2 parents a367191 + 7305ba9
commit 53b249f
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/Common/x64Emitter.cpp b/Common/x64Emitter.cpp
@@ -501,7 +501,8 @@ void XEmitter::SetJumpTarget(const FixupBranch &branch)
 	{
 		s64 distance = (s64)(code - branch.ptr);
 		_assert_msg_(distance >= -0x80000000LL && distance < 0x80000000LL, "Jump target too far away, needs indirect register");
-		((s32*)branch.ptr)[-1] = (s32)distance;
+		const s32 distance32 = static_cast<s32>(distance);
+		std::memcpy(branch.ptr - sizeof(s32), &distance32, sizeof(s32));
 	}
 }
 

diff --git a/Common/x64Emitter.h b/Common/x64Emitter.h
@@ -20,6 +20,7 @@
 #include "ppsspp_config.h"
 
 #include <cstddef>
+#include <cstring>
 
 #include "Common/Common.h"
 #include "Common/Log.h"
@@ -361,9 +362,9 @@ class XEmitter
 
 protected:
 	inline void Write8(u8 value)   {*code++ = value;}
-	inline void Write16(u16 value) {*(u16*)code = (value); code += 2;}
-	inline void Write32(u32 value) {*(u32*)code = (value); code += 4;}
-	inline void Write64(u64 value) {*(u64*)code = (value); code += 8;}
+	inline void Write16(u16 value) {std::memcpy(code, &value, sizeof(u16)); code += 2;}
+	inline void Write32(u32 value) {std::memcpy(code, &value, sizeof(u32)); code += 4;}
+	inline void Write64(u64 value) {std::memcpy(code, &value, sizeof(u64)); code += 8;}
 
 public:
 	XEmitter() { code = nullptr; flags_locked = false; }