llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-backend-sparc @llvm/pr-subscribers-clang-codegen Author: Koakuma (koachan) <details> <summary>Changes</summary> Make sure that empty structs are treated as if it has a size of one bit in function parameters and return types so that it occupies a full argument and/or return register slot. This fixes crashes and miscompilations when passing and/or returning empty structs. --- Full diff: https://github.com/llvm/llvm-project/pull/90338.diff 2 Files Affected: - (modified) clang/lib/CodeGen/Targets/Sparc.cpp (+4-1) - (modified) clang/test/CodeGen/sparcv9-abi.c (+6) ``````````diff diff --git a/clang/lib/CodeGen/Targets/Sparc.cpp b/clang/lib/CodeGen/Targets/Sparc.cpp index 9025a633f328e2..b82e9a69e19671 100644 --- a/clang/lib/CodeGen/Targets/Sparc.cpp +++ b/clang/lib/CodeGen/Targets/Sparc.cpp @@ -263,7 +263,10 @@ SparcV9ABIInfo::classifyType(QualType Ty, unsigned SizeLimit) const { CoerceBuilder CB(getVMContext(), getDataLayout()); CB.addStruct(0, StrTy); - CB.pad(llvm::alignTo(CB.DL.getTypeSizeInBits(StrTy), 64)); + // All structs, even empty ones, should take up a register argument slot, + // so pin the minimum struct size to one bit. + CB.pad(llvm::alignTo( + std::max(CB.DL.getTypeSizeInBits(StrTy).getKnownMinValue(), 1UL), 64)); // Try to use the original type for coercion. llvm::Type *CoerceTy = CB.isUsableType(StrTy) ? StrTy : CB.getType(); diff --git a/clang/test/CodeGen/sparcv9-abi.c b/clang/test/CodeGen/sparcv9-abi.c index 5e74a9a883cefa..360bd9d9019e56 100644 --- a/clang/test/CodeGen/sparcv9-abi.c +++ b/clang/test/CodeGen/sparcv9-abi.c @@ -21,6 +21,12 @@ char f_int_4(char x) { return x; } // CHECK-LABEL: define{{.*}} fp128 @f_ld(fp128 noundef %x) long double f_ld(long double x) { return x; } +// Empty struct is lowered as a placeholder word parameter. +struct empty {}; + +// CHECK-LABEL: define{{.*}} i64 @f_empty(i64 %x.coerce) +struct empty f_empty(struct empty x) { return x; } + // Small structs are passed in registers. struct small { int *a, *b; `````````` </details> https://github.com/llvm/llvm-project/pull/90338 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
