auto-sync BitCastStdArray.py: Transform to union instead (#2257)

* auto-sync BitCastStdArray.py: Transform to `union` instead * Do `typeof` manually for MSVC
capstone-engine · Jan 24, 2024 · cb2b879 · cb2b879
1 parent eaf6d7a
commit cb2b879
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Showing 2 changed files with 41 additions and 12 deletions.
diff --git a/arch/AArch64/AArch64AddressingModes.h b/arch/AArch64/AArch64AddressingModes.h
@@ -827,12 +827,12 @@ static inline uint64_t AArch64_AM_decodeAdvSIMDModImmType12(uint8_t Imm)
 #define DEFINE_isSVEMaskOfIdenticalElements(T)                                 \
 	static inline bool CONCAT(AArch64_AM_isSVEMaskOfIdenticalElements, T)(int64_t Imm)    \
 	{                                                                          \
-		union {                                   \
-			uint64_t L;                                   \
-			T A[sizeof(int64_t) / sizeof(T)];                                   \
-		} U;                                   \
-		U.L = Imm;                                   \
-		T *Parts = U.A;                                   \
+		union { \
+			int64_t In; \
+			T Out[sizeof(int64_t) / sizeof(T)]; \
+		} U_Parts; \
+		U_Parts.In = Imm; \
+		T *Parts = U_Parts.Out; \
 		for (int i = 0; i < (sizeof(int64_t) / sizeof(T)); i++) {   \
 			if (Parts[i] != Parts[0]) \
 				return false; \
@@ -887,9 +887,24 @@ AArch64_AM_isSVEMoveMaskPreferredLogicalImmediate(int64_t Imm)
 	if (isSVECpyImm64(Imm))
 		return false;
 
-	int32_t *S = (int32_t *)(&(Imm)); // arr len =  2
-	int16_t *H = (int16_t *)(&(Imm)); // arr len =  4
-	int8_t *B = (int8_t *)(&(Imm));	  // arr len =  8
+	union {
+		int64_t In;
+		int32_t Out[2];
+	} U_S;
+	U_S.In = Imm;
+	int32_t *S = U_S.Out;
+	union {
+		int64_t In;
+		int16_t Out[4];
+	} U_H;
+	U_H.In = Imm;
+	int16_t *H = U_H.Out;
+	union {
+		int64_t In;
+		int8_t Out[8];
+	} U_B;
+	U_B.In = Imm;
+	int8_t *B = U_B.Out;
 
 	if (CONCAT(AArch64_AM_isSVEMaskOfIdenticalElements, int32_t)(Imm) &&
 		isSVECpyImm32(S[0]))

diff --git a/suite/auto-sync/Updater/CppTranslator/Patches/BitCastStdArray.py b/suite/auto-sync/Updater/CppTranslator/Patches/BitCastStdArray.py
@@ -7,7 +7,14 @@
 class BitCastStdArray(Patch):
     """
     Patch   auto S = bit_cast<std::array<int32_t, 2>>(Imm);
-    to      int32_t *S = ((int32_t *)(&Imm)); // Array length = 2
+    to      union {
+                typeof(Imm) In;
+                int32_t Out[2];
+            } U_S;
+            U_S.In = Imm;
+            int32_t *S = U_S.Out;
+
+            MSVC doesn't support typeof so it has to be resolved manually.
     """
 
     def __init__(self, priority: int):
@@ -38,8 +45,15 @@ def get_main_capture_name(self) -> str:
     def get_patch(self, captures: [(Node, str)], src: bytes, **kwargs) -> bytes:
         arr_name: bytes = captures[1][0].text
         array_type: Node = captures[3][0]
-        cast_target: bytes = captures[4][0].text
+        cast_target: bytes = captures[4][0].text.strip(b"()")
         array_templ_args: bytes = array_type.named_children[0].named_children[1].named_children[1].text.strip(b"<>")
         arr_type = array_templ_args.split(b",")[0]
         arr_len = array_templ_args.split(b",")[1]
-        return arr_type + b" *" + arr_name + b" = (" + arr_type + b"*)(&" + cast_target + b"); // arr len = " + arr_len
+        return (
+            b"union {\n"
+            + b"    typeof(" + cast_target + b") In;\n"
+            + b"    " + arr_type + b" Out[" + arr_len + b"];\n"
+            + b"} U_" + arr_name + b";\n"
+            + b"U_" + arr_name + b".In = " + cast_target + b";\n"
+            + arr_type + b" *" + arr_name + b" = U_" + arr_name + b".Out;"
+        )