[RISCV] Support ABI checking with per function target-features

1. if users don't specific -mattr, the default target-feature come
from IR attribute.
2. fixed bug and re-land this patch

Reviewers: lenary, asb

Reviewed By: lenary

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70837

(cherry picked from commit 0cb274d)

Author: zakk0610

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -194,6 +194,19 @@ class RISCVAsmParser : public MCTargetAsmParser {
     Parser.addAliasForDirective(".word", ".4byte");
     Parser.addAliasForDirective(".dword", ".8byte");
     setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
+
+    auto ABIName = StringRef(Options.ABIName);
+    if (ABIName.endswith("f") &&
+        !getSTI().getFeatureBits()[RISCV::FeatureStdExtF]) {
+      errs() << "Hard-float 'f' ABI can't be used for a target that "
+                "doesn't support the F instruction set extension (ignoring "
+                "target-abi)\n";
+    } else if (ABIName.endswith("d") &&
+               !getSTI().getFeatureBits()[RISCV::FeatureStdExtD]) {
+      errs() << "Hard-float 'd' ABI can't be used for a target that "
+                "doesn't support the D instruction set extension (ignoring "
+                "target-abi)\n";
+    }
   }
 };
 

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -51,6 +51,20 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
   RISCVABI::ABI ABI = Subtarget.getTargetABI();
   assert(ABI != RISCVABI::ABI_Unknown && "Improperly initialised target ABI");
 
+  if ((ABI == RISCVABI::ABI_ILP32F || ABI == RISCVABI::ABI_LP64F) &&
+      !Subtarget.hasStdExtF()) {
+    errs() << "Hard-float 'f' ABI can't be used for a target that "
+                "doesn't support the F instruction set extension (ignoring "
+                          "target-abi)\n";
+    ABI = Subtarget.is64Bit() ? RISCVABI::ABI_LP64 : RISCVABI::ABI_ILP32;
+  } else if ((ABI == RISCVABI::ABI_ILP32D || ABI == RISCVABI::ABI_LP64D) &&
+             !Subtarget.hasStdExtD()) {
+    errs() << "Hard-float 'd' ABI can't be used for a target that "
+              "doesn't support the D instruction set extension (ignoring "
+              "target-abi)\n";
+    ABI = Subtarget.is64Bit() ? RISCVABI::ABI_LP64 : RISCVABI::ABI_ILP32;
+  }
+
   switch (ABI) {
   default:
     report_fatal_error("Don't know how to lower this ABI");

llvm/lib/Target/RISCV/Utils/RISCVBaseInfo.cpp

@@ -28,17 +28,8 @@ ABI computeTargetABI(const Triple &TT, FeatureBitset FeatureBits,
     errs() << "64-bit ABIs are not supported for 32-bit targets (ignoring "
               "target-abi)\n";
     TargetABI = ABI_Unknown;
-  } else if (ABIName.endswith("f") && !FeatureBits[RISCV::FeatureStdExtF]) {
-    errs() << "Hard-float 'f' ABI can't be used for a target that "
-              "doesn't support the F instruction set extension (ignoring "
-              "target-abi)\n";
-    TargetABI = ABI_Unknown;
-  } else if (ABIName.endswith("d") && !FeatureBits[RISCV::FeatureStdExtD]) {
-    errs() << "Hard-float 'd' ABI can't be used for a target that "
-              "doesn't support the D instruction set extension (ignoring "
-              "target-abi)\n";
-    TargetABI = ABI_Unknown;
   } else if (IsRV32E && TargetABI != ABI_ILP32E && TargetABI != ABI_Unknown) {
+    // TODO: move this checking to RISCVTargetLowering and RISCVAsmParser
     errs()
         << "Only the ilp32e ABI is supported for RV32E (ignoring target-abi)\n";
     TargetABI = ABI_Unknown;

llvm/test/CodeGen/RISCV/subtarget-features-std-ext.ll

@@ -2,12 +2,17 @@
 ; RUN:   | FileCheck -check-prefix=RV32IF-ILP32 %s
 ; RUN: llc -mtriple=riscv32 -target-abi ilp32f < %s 2>&1 \
 ; RUN:   | FileCheck -check-prefix=RV32IF-ILP32F %s
+; RUN: llc -mtriple=riscv32 -mattr=-f -target-abi ilp32f <%s 2>&1 \
+; RUN:   | FileCheck -check-prefix=RV32I-ILP32F-FAILED %s
+
+; RV32I-ILP32F-FAILED: Hard-float 'f' ABI can't be used for a target that doesn't support the F instruction set extension
 
-; RV32IF-ILP32F: Hard-float 'f' ABI can't be used for a target that doesn't support the F instruction set extension (ignoring target-abi)
 
 define float @foo(i32 %a) nounwind #0 {
-; RV32IF-ILP32: # %bb.0:
-; RV32IF-ILP32-NEXT: fcvt.s.w  ft0, a0
+; RV32IF-ILP32: fcvt.s.w  ft0, a0
+; RV32IF-ILP32-NEXT: fmv.x.w a0, ft0
+; RV32IF-ILP32F: fcvt.s.w fa0, a0
+; RV32IF-ILP32F-NEXT: ret
   %conv = sitofp i32 %a to float
   ret float %conv
 }