[RISCV][LTO] enable LTO/ThinLTO on RISCV (D78035)

clang/lib/Driver/ToolChains/RISCVToolchain.cpp

@@ -159,6 +159,12 @@ void RISCV::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   std::string Linker = getToolChain().GetLinkerPath();
 
+  if (D.isUsingLTO()) {
+    assert(!Inputs.empty() && "Must have at least one input.");
+    addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
+                  D.getLTOMode() == LTOK_Thin);
+  }
+
   bool WantCRTs =
       !Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles);
 

clang/lib/Driver/ToolChains/RISCVToolchain.h

@@ -26,6 +26,7 @@ class LLVM_LIBRARY_VISIBILITY RISCVToolChain : public Generic_ELF {
   void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
                              llvm::opt::ArgStringList &CC1Args,
                              Action::OffloadKind) const override;
+  bool HasNativeLLVMSupport() const override { return true; }
   RuntimeLibType GetDefaultRuntimeLibType() const override;
   UnwindLibType
   GetUnwindLibType(const llvm::opt::ArgList &Args) const override;

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -109,6 +109,19 @@ RISCVTargetMachine::getSubtargetImpl(const Function &F) const {
   return I.get();
 }
 
+void RISCVTargetMachine::setTargetOptionsWithModuleMetadata(
+    const Module &M LLVM_ATTRIBUTE_UNUSED) {
+  StringRef ABIName = Options.MCOptions.getABIName();
+  if (const MDString *ModuleTargetABI =
+          dyn_cast_or_null<MDString>(M.getModuleFlag("target-abi"))) {
+    StringRef ModuleABIName = ModuleTargetABI->getString();
+    if (!ABIName.empty() && ModuleABIName != ABIName)
+      report_fatal_error("-target-abi option != target-abi module flag");
+    if (ABIName.empty())
+      Options.MCOptions.ABIName = ModuleABIName.str();
+  }
+}
+
 TargetTransformInfo
 RISCVTargetMachine::getTargetTransformInfo(const Function &F) {
   return TargetTransformInfo(RISCVTTIImpl(this, F));

llvm/lib/Target/RISCV/RISCVTargetMachine.h

@@ -42,6 +42,9 @@ class RISCVTargetMachine : public LLVMTargetMachine {
     return TLOF.get();
   }
 
+  void setTargetOptionsWithModuleMetadata(
+      const Module &M LLVM_ATTRIBUTE_UNUSED) override;
+
   TargetTransformInfo getTargetTransformInfo(const Function &F) override;
 
   virtual bool isNoopAddrSpaceCast(unsigned SrcAS,

llvm/test/LTO/RISCV/Inputs/mabi-invalid.ll

@@ -0,0 +1,14 @@
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+target triple = "riscv32-unknown-linux-gnu"
+
+define float @foo(float %x) #0 {
+  %conv = fpext float %x to double
+  %add = fadd double %conv, 0x400921FD80C9BEFB
+  %conv1 = fptrunc double %add to float
+  ret float %conv1
+}
+
+attributes #0 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"ilp32"}

llvm/test/LTO/RISCV/Inputs/mabi.ll

@@ -0,0 +1,14 @@
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+target triple = "riscv32-unknown-linux-gnu"
+
+define float @foo(float %x) #0 {
+  %conv = fpext float %x to double
+  %add = fadd double %conv, 0x400921FD80C9BEFB
+  %conv1 = fptrunc double %add to float
+  ret float %conv1
+}
+
+attributes #0 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"ilp32f"}

llvm/test/LTO/RISCV/lit.local.cfg

@@ -0,0 +1,2 @@
+if not 'RISCV' in config.root.targets:
+  config.unsupported = True

llvm/test/LTO/RISCV/mabi-invalid.ll

@@ -0,0 +1,35 @@
+; Check with regular LTO
+; RUN: rm -f %t*
+; RUN: llvm-as < %s >%t1
+; RUN: llvm-as < %p/Inputs/mabi-invalid.ll >%t2
+; Check old API
+; RUN: not llvm-lto -exported-symbol=main  -o %t3 %t1 %t2 2>&1 | FileCheck %s
+; Check new API
+; RUN: not llvm-lto2 run -r %t1,foo, -r %t1,main,plx -r %t2,foo,plx -o %t3.o %t1 %t2 2>&1 | FileCheck %s
+
+; Check with ThinLTO.
+; RUN: rm -f %t*
+; RUN: opt -module-summary -o %t1 %s
+; RUN: opt -module-summary -o %t2 %p/Inputs/mabi-invalid.ll
+; Check old API
+; RUN: not --crash llvm-lto -thinlto -thinlto-action=run %t1 %t2 -exported-symbol=main 2>&1 | FileCheck %s
+; Check new API
+; RUN: not --crash llvm-lto2 run -r %t1,foo, -r %t1,main,plx -r %t2,foo,plx -o %t3.o %t1 %t2 2>&1 | FileCheck %s
+
+; CHECK: 'target-abi': IDs have conflicting values
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+target triple = "riscv32-unknown-linux-gnu"
+
+declare float @foo(float) #1
+
+define float @main(float %x) #0 {
+  %retval = call float @foo(float 10.0)
+  ret float %retval
+}
+
+attributes #0 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+attributes #1 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"ilp32f"}

llvm/test/LTO/RISCV/mabi.ll

@@ -0,0 +1,44 @@
+; Test target-abi module flag generate correct elf flags.
+
+; Check with regular LTO
+; RUN: rm -f %t*
+; RUN: llvm-as < %s >%t1
+; RUN: llvm-as < %p/Inputs/mabi.ll >%t2
+; Check old API
+; RUN: llvm-lto -exported-symbol=main  -o %t3 %t1 %t2
+; RUN: llvm-readelf -h %t3 | FileCheck %s
+; Check new API
+; RUN: llvm-lto2 run -r %t1,foo, -r %t1,main,plx -r %t2,foo,plx -o %t3.o %t1 %t2
+; RUN: llvm-readelf -h %t3.o.0 | FileCheck %s
+
+; Check with ThinLTO.
+; RUN: rm -f %t*
+; RUN: opt -module-summary -o %t1 %s
+; RUN: opt -module-summary -o %t2 %p/Inputs/mabi.ll
+; Check old API
+; RUN: llvm-lto -thinlto -thinlto-action=run %t1 %t2 -exported-symbol=main
+; RUN: llvm-readelf -h %t1.thinlto.o | FileCheck %s
+; RUN: llvm-readelf -h %t2.thinlto.o | FileCheck %s
+; Check new API
+; RUN: llvm-lto2 run -r %t1,foo, -r %t1,main,plx -r %t2,foo,plx -o %t3.o %t1 %t2
+; RUN: llvm-readelf -h %t3.o.1 | FileCheck %s
+; RUN: llvm-readelf -h %t3.o.2 | FileCheck %s
+
+; CHECK: Flags: 0x2, single-float ABI
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+target triple = "riscv32-unknown-linux-gnu"
+
+declare float @foo(float) #1
+
+define float @main(float %x) #0 {
+  %retval = call float @foo(float 10.0)
+  ret float %retval
+}
+
+attributes #0 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+attributes #1 = { nounwind "target-features"="+a,+c,+f,+m,+relax" }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"ilp32f"}
+