From 039b970c97cf557b2bdb0fb72188cedb8fff31ad Mon Sep 17 00:00:00 2001 From: Roman Divacky Date: Sat, 20 Feb 2016 08:31:24 +0000 Subject: [PATCH] Fix handling of vaargs on PPC32 when going from regsave to overflow. It can happen that when we only have 1 more register left in the regsave area we need to store a value bigger than 1 register and therefore we go to the overflow area. In this case we have to leave the last slot in the regsave area unused and keep using overflow area. Do this by storing a limit value to the used register counter in the overflow block. Issue diagnosed by and solution tested by Mark Millard! llvm-svn: 261422 --- clang/lib/CodeGen/TargetInfo.cpp | 5 ++++- clang/test/CodeGen/ppc-varargs-struct.c | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp index bbc6b3b1ae28..8a5cc6c3df87 100644 --- a/clang/lib/CodeGen/TargetInfo.cpp +++ b/clang/lib/CodeGen/TargetInfo.cpp @@ -3505,6 +3505,7 @@ public: Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAList, QualType Ty) const { + const unsigned OverflowLimit = 8; if (const ComplexType *CTy = Ty->getAs()) { // TODO: Implement this. For now ignore. (void)CTy; @@ -3547,7 +3548,7 @@ Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAList, } llvm::Value *CC = - Builder.CreateICmpULT(NumRegs, Builder.getInt8(8), "cond"); + Builder.CreateICmpULT(NumRegs, Builder.getInt8(OverflowLimit), "cond"); llvm::BasicBlock *UsingRegs = CGF.createBasicBlock("using_regs"); llvm::BasicBlock *UsingOverflow = CGF.createBasicBlock("using_overflow"); @@ -3599,6 +3600,8 @@ Address PPC32_SVR4_ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAList, { CGF.EmitBlock(UsingOverflow); + Builder.CreateStore(Builder.getInt8(OverflowLimit), NumRegsAddr); + // Everything in the overflow area is rounded up to a size of at least 4. CharUnits OverflowAreaAlign = CharUnits::fromQuantity(4); diff --git a/clang/test/CodeGen/ppc-varargs-struct.c b/clang/test/CodeGen/ppc-varargs-struct.c index 1ad57c26b485..d7936a126960 100644 --- a/clang/test/CodeGen/ppc-varargs-struct.c +++ b/clang/test/CodeGen/ppc-varargs-struct.c @@ -37,6 +37,7 @@ void testva (int n, ...) // CHECK-PPC-NEXT: br label %[[CONT:[a-z0-9]+]] // // CHECK-PPC:[[USING_OVERFLOW]] +// CHECK-PPC-NEXT: store i8 8, i8* [[GPRPTR]], align 4 // CHECK-PPC-NEXT: [[OVERFLOW_AREA_P:%[0-9]+]] = getelementptr inbounds %struct.__va_list_tag, %struct.__va_list_tag* [[ARRAYDECAY]], i32 0, i32 3 // CHECK-PPC-NEXT: [[OVERFLOW_AREA:%.+]] = load i8*, i8** [[OVERFLOW_AREA_P]], align 4 // CHECK-PPC-NEXT: %{{[0-9]+}} = ptrtoint i8* %argp.cur to i32 @@ -76,6 +77,7 @@ void testva (int n, ...) // CHECK-PPC-NEXT: br label %[[CONT:[a-z0-9]+]] // // CHECK-PPC:[[USING_OVERFLOW]] +// CHECK-PPC-NEXT: store i8 8, i8* [[GPRPTR]], align 4 // CHECK-PPC-NEXT: [[OVERFLOW_AREA_P:%[0-9]+]] = getelementptr inbounds %struct.__va_list_tag, %struct.__va_list_tag* [[ARRAYDECAY]], i32 0, i32 3 // CHECK-PPC-NEXT: [[OVERFLOW_AREA:%.+]] = load i8*, i8** [[OVERFLOW_AREA_P]], align 4 // CHECK-PPC-NEXT: [[MEMADDR:%.+]] = bitcast i8* [[OVERFLOW_AREA]] to i32*