[llvm] [MSan] Separated PPC32 va_arg helper from PPC64 (PR #131827)

[Vitaly Buka via llvm-commits]

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@@ -6551,42 +6541,27 @@ struct VarArgPowerPC32Helper : public VarArgHelperBase {
   Value *VAArgSize = nullptr;
 
   VarArgPowerPC32Helper(Function &F, MemorySanitizer &MS,
-                        MemorySanitizerVisitor &MSV, unsigned VAListTagSize)
-      : VarArgHelperBase(F, MS, MSV, VAListTagSize) {}
+                        MemorySanitizerVisitor &MSV)
+      : VarArgHelperBase(F, MS, MSV, /*VAListTagSize=*/12) {}
 
   void visitCallBase(CallBase &CB, IRBuilder<> &IRB) override {
-    // For PowerPC, we need to deal with alignment of stack arguments -
-    // they are mostly aligned to 8 bytes, but vectors and i128 arrays
-    // are aligned to 16 bytes, byvals can be aligned to 8 or 16 bytes,
-    // For that reason, we compute current offset from stack pointer (which is
-    // always properly aligned), and offset for the first vararg, then subtract
-    // them.
     unsigned VAArgBase;
     Triple TargetTriple(F.getParent()->getTargetTriple());
-    // Parameter save area starts at 48 bytes from frame pointer for ABIv1,
-    // and 32 bytes for ABIv2.  This is usually determined by target
-    // endianness, but in theory could be overridden by function attribute.
-    if (TargetTriple.isPPC64()) {
-      if (TargetTriple.isPPC64ELFv2ABI())
-        VAArgBase = 32;
-      else
-        VAArgBase = 48;
-    } else {
-      // Parameter save area is 8 bytes from frame pointer in PPC32
-      VAArgBase = 8;
-    }
+    // Parameter save area is 8 bytes from frame pointer in PPC32
+    VAArgBase = 8;
     unsigned VAArgOffset = VAArgBase;
     const DataLayout &DL = F.getDataLayout();
+    unsigned IntptrSize = DL.getTypeStoreSize(MS.IntptrTy);
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vitalybuka wrote:

maybe assert(IntptrSize == 4) ?

https://github.com/llvm/llvm-project/pull/131827