ARM: Fix assertion caused by passing bitfield struct using ABIArgInfo::getExpandWithPadding

[olista01]

Summary

In cases where a struct must, according to the AAPCS, not be split between general purpose and floating point registers, we use ABIArgInfo::getExpandWithPadding to add the padding arguments. However, ExpandWithPadding does not work if the struct contains bitfields, so we instead must use ABIArgInfo::getDirect.

[t.p.northover]

Hi Oliver,

I think this looks good.

Cheers.

Tim.

[olista01]

Thanks, Committed revision 208185.

lib/CodeGen/TargetInfo.cpp

for (auto &I : FI.arguments()) {
     // the stack. If this situation occurs, we add padding to prevent the
     // GPRs from being used. In this situiation, the current argument could
     // only be allocated by rule C.8, so rule C.6 would mark these GPRs as
     // unusable anyway.
     const bool StackUsed = PreAllocationGPRs > NumGPRs || PreAllocationVFPs > NumVFPs;
     if (!IsCPRC && PreAllocationGPRs < NumGPRs && AllocatedGPRs > NumGPRs && StackUsed) {
       llvm::Type *PaddingTy = llvm::ArrayType::get(
           llvm::Type::getInt32Ty(getVMContext()), NumGPRs - PreAllocationGPRs);
-      I.info = ABIArgInfo::getExpandWithPadding(false, PaddingTy);
+      I.info = ABIArgInfo::getDirect(nullptr /* type */, 0 /* offset */,
+                                     PaddingTy);
     }
   }
 
   // Always honor user-specified calling convention.
   if (FI.getCallingConvention() != llvm::CallingConv::C)
     return;
 
   llvm::CallingConv::ID cc = getRuntimeCC();

test/CodeGen/arm-aapcs-vfp.c

 // CHECK-LABEL: define arm_aapcs_vfpcc void @f33(%struct.s33* byval align 1 %s)
 struct s33 { char buf[32*32]; };
 void f33(struct s33 s) { }
 
 typedef struct { long long x; int y; } struct_long_long_int;
 // CHECK: define arm_aapcs_vfpcc void @test_vfp_stack_gpr_split_1(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, i32 %j, i64 %k, i32 %l)
 void test_vfp_stack_gpr_split_1(double a, double b, double c, double d, double e, double f, double g, double h, double i, int j, long long k, int l) {}
 
-// CHECK: define arm_aapcs_vfpcc void @test_vfp_stack_gpr_split_2(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, i32 %j, [3 x i32], i64 %k.0, i32 %k.1)
+// CHECK: define arm_aapcs_vfpcc void @test_vfp_stack_gpr_split_2(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, i32 %j, [3 x i32], i64 %k.coerce0, i32 %k.coerce1)
 void test_vfp_stack_gpr_split_2(double a, double b, double c, double d, double e, double f, double g, double h, double i, int j, struct_long_long_int k) {}
 
-// CHECK: define arm_aapcs_vfpcc void @test_vfp_stack_gpr_split_3(%struct.struct_long_long_int* noalias sret %agg.result, double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, [3 x i32], i64 %k.0, i32 %k.1)
+// CHECK: define arm_aapcs_vfpcc void @test_vfp_stack_gpr_split_3(%struct.struct_long_long_int* noalias sret %agg.result, double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, [3 x i32], i64 %k.coerce0, i32 %k.coerce1)
 struct_long_long_int test_vfp_stack_gpr_split_3(double a, double b, double c, double d, double e, double f, double g, double h, double i, struct_long_long_int k) {}
+
+typedef struct { int a; int b:4; int c; } struct_int_bitfield_int;
+// CHECK: define arm_aapcs_vfpcc void @test_test_vfp_stack_gpr_split_bitfield(double %a, double %b, double %c, double %d, double %e, double %f, double %g, double %h, double %i, i32 %j, i32 %k, [2 x i32], i32 %l.coerce0, i8 %l.coerce1, i32 %l.coerce2)
+void test_test_vfp_stack_gpr_split_bitfield(double a, double b, double c, double d, double e, double f, double g, double h, double i, int j, int k, struct_int_bitfield_int l) {}