[clang] [SystemZ][z/OS] Implement z/OS XPLINK ABI (PR #91384)

[Ulrich Weigand via cfe-commits]

================
@@ -0,0 +1,137 @@
+// RUN: %clang_cc1 -triple s390x-ibm-zos \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-feature +vector \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu z13 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu arch11 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu z14 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu arch12 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu z15 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple s390x-ibm-zos -target-cpu arch13 \
+// RUN:   -emit-llvm -no-enable-noundef-analysis -o - %s | FileCheck %s
+
+// Scalar types
+
+char pass_char(char arg) { return arg; }
+// CHECK-LABEL: define signext i8 @pass_char(i8 signext %{{.*}})
+
+short pass_short(short arg) { return arg; }
+// CHECK-LABEL: define signext i16 @pass_short(i16 signext %{{.*}})
+
+int pass_int(int arg) { return arg; }
+// CHECK-LABEL: define signext i32 @pass_int(i32 signext %{{.*}})
+
+long pass_long(long arg) { return arg; }
+// CHECK-LABEL: define i64 @pass_long(i64 %{{.*}})
+
+long long pass_longlong(long long arg) { return arg; }
+// CHECK-LABEL: define i64 @pass_longlong(i64 %{{.*}})
+
+float pass_float(float arg) { return arg; }
+// CHECK-LABEL: define float @pass_float(float %{{.*}})
+
+double pass_double(double arg) { return arg; }
+// CHECK-LABEL: define double @pass_double(double %{{.*}})
+
+long double pass_longdouble(long double arg) { return arg; }
+// CHECK-LABEL: define fp128 @pass_longdouble(fp128 %{{.*}})
+
+enum Color { Red, Blue };
+enum Color pass_enum(enum Color arg) { return arg; }
+// CHECK-LABEL: define zeroext i32 @pass_enum(i32 zeroext %{{.*}})
+
+// Complex types
+
+// TODO: Add tests for complex integer types
+
+_Complex float pass_complex_float(_Complex float arg) { return arg; }
+// CHECK-LABEL: define { float, float } @pass_complex_float(float %{{.*}}, float %{{.*}})
+
+_Complex double pass_complex_double(_Complex double arg) { return arg; }
+// CHECK-LABEL: define { double, double } @pass_complex_double(double %{{.*}}, double %{{.*}})
+
+_Complex long double pass_complex_longdouble(_Complex long double arg) { return arg; }
+// CHECK-LABEL: define { fp128, fp128 } @pass_complex_longdouble(fp128 %{{.*}}, fp128 %{{.*}})
+
+// Verify that the following are complex-like types
+struct complexlike_float { float re, im; };
+struct complexlike_float pass_complexlike_float(struct complexlike_float arg) { return arg; }
+// CHECK-LABEL: define %struct.complexlike_float @pass_complexlike_float(float %{{.*}}, float %{{.*}})
+
+struct complexlike_double { double re, im; };
+struct complexlike_double pass_complexlike_double(struct complexlike_double arg) { return arg; }
+// CHECK-LABEL: define %struct.complexlike_double @pass_complexlike_double(double %{{.*}}, double %{{.*}})
+
+struct complexlike_longdouble { long double re, im; };
+struct complexlike_longdouble pass_complexlike_longdouble(struct complexlike_longdouble arg) { return arg; }
+// CHECK-LABEL: define %struct.complexlike_longdouble @pass_complexlike_longdouble(fp128 %{{.*}}, fp128 %{{.*}})
+
+// Aggregate types
+
----------------
uweigand wrote:

We probably ought to increase test coverage to handle more cases, in particular unnamed arguments, and some of the special cases of what counts and does not count as "single-element struct".

https://github.com/llvm/llvm-project/pull/91384