[RISCV][Clang] Compute the default target-abi if it's empty.

Every generated IR has a corresponding target-abi value, so
encoding a non-empty value would improve the robustness and
correctness.

Reviewed By: asb, jrtc27, arichardson

Differential Revision: https://reviews.llvm.org/D105555

Author: zakk0610

clang/lib/Basic/Targets/RISCV.cpp

@@ -246,6 +246,9 @@ bool RISCVTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
     ISAInfo = std::move(*ParseResult);
   }
 
+  if (ABI.empty())
+    ABI = llvm::RISCV::computeDefaultABIFromArch(*ISAInfo).str();
+
   return true;
 }
 

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

@@ -194,27 +194,11 @@ StringRef riscv::getRISCVABI(const ArgList &Args, const llvm::Triple &Triple) {
 
   auto ParseResult = llvm::RISCVISAInfo::parseArchString(
       Arch, /* EnableExperimentalExtension */ true);
-  if (!ParseResult) {
+  if (!ParseResult)
     // Ignore parsing error, just go 3rd step.
     consumeError(ParseResult.takeError());
-  } else {
-    auto &ISAInfo = *ParseResult;
-    bool HasD = ISAInfo->hasExtension("d");
-    unsigned XLen = ISAInfo->getXLen();
-    if (XLen == 32) {
-      bool HasE = ISAInfo->hasExtension("e");
-      if (HasD)
-        return "ilp32d";
-      if (HasE)
-        return "ilp32e";
-      return "ilp32";
-    } else if (XLen == 64) {
-      if (HasD)
-        return "lp64d";
-      return "lp64";
-    }
-    llvm_unreachable("unhandled XLen");
-  }
+  else
+    return llvm::RISCV::computeDefaultABIFromArch(**ParseResult);
 
   // 3. Choose a default based on the triple
   //

clang/test/CodeGen/RISCV/riscv-metadata.c

@@ -1,14 +1,28 @@
+// RUN: %clang_cc1 -triple riscv32 -emit-llvm -o - %s | FileCheck -check-prefix=EMPTY-ILP32 %s
+// RUN: %clang_cc1 -triple riscv32 -emit-llvm -target-feature +f -target-feature +d -o - %s | FileCheck -check-prefix=EMPTY-ILP32D %s
 // RUN: %clang_cc1 -triple riscv32 -target-abi ilp32 -emit-llvm -o - %s | FileCheck -check-prefix=ILP32 %s
 // RUN: %clang_cc1 -triple riscv32 -target-feature +f -target-abi ilp32f -emit-llvm -o - %s | FileCheck -check-prefix=ILP32F %s
 // RUN: %clang_cc1 -triple riscv32 -target-feature +d -target-feature +f -target-abi ilp32d -emit-llvm -o - %s | FileCheck -check-prefix=ILP32D %s
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - %s | FileCheck -check-prefix=EMPTY-LP64 %s
+// RUN: %clang_cc1 -triple riscv64 -target-feature +f -target-feature +d -emit-llvm -o - %s | FileCheck -check-prefix=EMPTY-LP64D %s
 // RUN: %clang_cc1 -triple riscv64 -target-abi lp64 -emit-llvm -o - %s | FileCheck -check-prefix=LP64 %s
 // RUN: %clang_cc1 -triple riscv64 -target-feature +f -target-abi lp64f -emit-llvm -o - %s | FileCheck -check-prefix=LP64F %s
 // RUN: %clang_cc1 -triple riscv64 -target-feature +d -target-feature +f -target-abi lp64d -emit-llvm -o - %s | FileCheck -check-prefix=LP64D %s
 
+// Test expected behavior when giving -target-cpu
+// This cc1 test is similar to clang with -march=rv32ifd -mcpu=sifive-e31, default abi is ilp32d
+// RUN: %clang_cc1 -triple riscv32 -emit-llvm -target-feature +f -target-feature +d -target-cpu sifive-e31 -o - %s | FileCheck -check-prefix=EMPTY-ILP32D %s
+// This cc1 test is similar to clang with -march=rv64i -mcpu=sifive-u74, default abi is lp64
+// RUN: %clang_cc1 -triple riscv64 -emit-llvm -o - -target-cpu sifive-u74 %s | FileCheck -check-prefix=EMPTY-LP64 %s
+
+// EMPTY-ILP32: !{{[0-9]+}} = !{i32 1, !"target-abi", !"ilp32"}
+// EMPTY-ILP32D: !{{[0-9]+}} = !{i32 1, !"target-abi", !"ilp32d"}
 // ILP32: !{{[0-9]+}} = !{i32 1, !"target-abi", !"ilp32"}
 // ILP32F: !{{[0-9]+}} = !{i32 1, !"target-abi", !"ilp32f"}
 // ILP32D: !{{[0-9]+}} = !{i32 1, !"target-abi", !"ilp32d"}
 
+// EMPTY-LP64: !{{[0-9]+}} = !{i32 1, !"target-abi", !"lp64"}
+// EMPTY-LP64D: !{{[0-9]+}} = !{i32 1, !"target-abi", !"lp64d"}
 // LP64: !{{[0-9]+}} = !{i32 1, !"target-abi", !"lp64"}
 // LP64F: !{{[0-9]+}} = !{i32 1, !"target-abi", !"lp64f"}
 // LP64D: !{{[0-9]+}} = !{i32 1, !"target-abi", !"lp64d"}

llvm/include/llvm/Support/TargetParser.h

@@ -17,8 +17,9 @@
 // FIXME: vector is used because that's what clang uses for subtarget feature
 // lists, but SmallVector would probably be better
 #include "llvm/ADT/Triple.h"
-#include "llvm/Support/ARMTargetParser.h"
 #include "llvm/Support/AArch64TargetParser.h"
+#include "llvm/Support/ARMTargetParser.h"
+#include "llvm/Support/RISCVISAInfo.h"
 #include <vector>
 
 namespace llvm {
@@ -174,6 +175,7 @@ void fillValidCPUArchList(SmallVectorImpl<StringRef> &Values, bool IsRV64);
 void fillValidTuneCPUArchList(SmallVectorImpl<StringRef> &Values, bool IsRV64);
 bool getCPUFeaturesExceptStdExt(CPUKind Kind, std::vector<StringRef> &Features);
 StringRef resolveTuneCPUAlias(StringRef TuneCPU, bool IsRV64);
+StringRef computeDefaultABIFromArch(const llvm::RISCVISAInfo &ISAInfo);
 
 } // namespace RISCV
 

llvm/lib/Support/TargetParser.cpp

@@ -331,6 +331,21 @@ bool getCPUFeaturesExceptStdExt(CPUKind Kind,
   return true;
 }
 
+StringRef computeDefaultABIFromArch(const llvm::RISCVISAInfo &ISAInfo) {
+  if (ISAInfo.getXLen() == 32) {
+    if (ISAInfo.hasExtension("d"))
+      return "ilp32d";
+    if (ISAInfo.hasExtension("e"))
+      return "ilp32e";
+    return "ilp32";
+  } else if (ISAInfo.getXLen() == 64) {
+    if (ISAInfo.hasExtension("d"))
+      return "lp64d";
+    return "lp64";
+  }
+  llvm_unreachable("Invalid XLEN");
+}
+
 } // namespace RISCV
 } // namespace llvm