commit fea4957177315f83746dca90cb4c9013eb465c46
author Alex Bradbury <asb@lowrisc.org> Sat Mar 09 09:28:06 2019 +0000
committer Alex Bradbury <asb@lowrisc.org> Sat Mar 09 09:28:06 2019 +0000
tree b9a9b764109fbfabbc1d2453688f2ae8c889b187
parent 972d7d514b2fbed4c256ce3a7e258e9e5e5a5ab9

[RISCV] Support -target-abi at the MC layer and for codegen

This patch adds proper handling of -target-abi, as accepted by llvm-mc and
llc. Lowering (codegen) for the hard-float ABIs will follow in a subsequent
patch. However, this patch does add MC layer support for the hard float and
RVE ABIs (emission of the appropriate ELF flags
https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#-file-header).

ABI parsing must be shared between codegen and the MC layer, so we add
computeTargetABI to RISCVUtils. A warning will be printed if an invalid or
unrecognized ABI is given.

Differential Revision: https://reviews.llvm.org/D59023

llvm-svn: 355771

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp

diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
index f7eae0b..40fa195 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp
@@ -11,7 +11,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "RISCVELFStreamer.h"
+#include "MCTargetDesc/RISCVAsmBackend.h"
 #include "RISCVMCTargetDesc.h"
+#include "Utils/RISCVBaseInfo.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 
@@ -22,14 +24,35 @@
                                                const MCSubtargetInfo &STI)
     : RISCVTargetStreamer(S) {
   MCAssembler &MCA = getStreamer().getAssembler();
-
   const FeatureBitset &Features = STI.getFeatureBits();
+  auto &MAB = static_cast<RISCVAsmBackend &>(MCA.getBackend());
+  RISCVABI::ABI ABI = MAB.getTargetABI();
+  assert(ABI != RISCVABI::ABI_Unknown && "Improperly initialised target ABI");
 
   unsigned EFlags = MCA.getELFHeaderEFlags();
 
   if (Features[RISCV::FeatureStdExtC])
     EFlags |= ELF::EF_RISCV_RVC;
 
+  switch (ABI) {
+  case RISCVABI::ABI_ILP32:
+  case RISCVABI::ABI_LP64:
+    break;
+  case RISCVABI::ABI_ILP32F:
+  case RISCVABI::ABI_LP64F:
+    EFlags |= ELF::EF_RISCV_FLOAT_ABI_SINGLE;
+    break;
+  case RISCVABI::ABI_ILP32D:
+  case RISCVABI::ABI_LP64D:
+    EFlags |= ELF::EF_RISCV_FLOAT_ABI_DOUBLE;
+    break;
+  case RISCVABI::ABI_ILP32E:
+    EFlags |= ELF::EF_RISCV_RVE;
+    break;
+  case RISCVABI::ABI_Unknown:
+    llvm_unreachable("Improperly initialised target ABI");
+  }
+
   MCA.setELFHeaderEFlags(EFlags);
 }