[clang] f1e0392 - [RISCV] Disable generation of asynchronous unwind tables for RISCV baremetal (#81727)

[via cfe-commits]

Author: Garvit Gupta
Date: 2024-02-23T20:01:58+08:00
New Revision: f1e0392b822e06f39c49df3ba594f4c98f608ba0

URL: https://github.com/llvm/llvm-project/commit/f1e0392b822e06f39c49df3ba594f4c98f608ba0
DIFF: https://github.com/llvm/llvm-project/commit/f1e0392b822e06f39c49df3ba594f4c98f608ba0.diff

LOG: [RISCV] Disable generation of asynchronous unwind tables for RISCV baremetal (#81727)

The below culprit patch enabled the generation of asynchronous unwind
tables (-funwind-tables=2) by default for RISCV for both linux and
RISCVToolChain baremetal object. However, since there are 2 baremetal
toolchain objects for RISCV, this created a discrepancy between their
behavior. Moreover, enabling the generation of asynchronous unwind
tables based on whether `-gcc-toolchain` option is present or not
doesn't seem to be the best criteria to decide on the same. This patch
make the behavior consistent by disabling the unwind tables in
RISCVToolChain Baremetal object.

Culprit Patch - https://reviews.llvm.org/D145164

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/RISCVToolchain.cpp
    clang/lib/Driver/ToolChains/RISCVToolchain.h
    clang/test/Driver/riscv-features.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
index 85beb945cbf6fc..624099d21ae124 100644
--- a/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
+++ b/clang/lib/Driver/ToolChains/RISCVToolchain.cpp
@@ -86,6 +86,11 @@ RISCVToolChain::GetUnwindLibType(const llvm::opt::ArgList &Args) const {
   return ToolChain::UNW_None;
 }
 
+ToolChain::UnwindTableLevel RISCVToolChain::getDefaultUnwindTableLevel(
+    const llvm::opt::ArgList &Args) const {
+  return UnwindTableLevel::None;
+}
+
 void RISCVToolChain::addClangTargetOptions(
     const llvm::opt::ArgList &DriverArgs,
     llvm::opt::ArgStringList &CC1Args,

diff  --git a/clang/lib/Driver/ToolChains/RISCVToolchain.h b/clang/lib/Driver/ToolChains/RISCVToolchain.h
index cec817ef7190be..fa0aa265d842bb 100644
--- a/clang/lib/Driver/ToolChains/RISCVToolchain.h
+++ b/clang/lib/Driver/ToolChains/RISCVToolchain.h
@@ -28,6 +28,8 @@ class LLVM_LIBRARY_VISIBILITY RISCVToolChain : public Generic_ELF {
   RuntimeLibType GetDefaultRuntimeLibType() const override;
   UnwindLibType
   GetUnwindLibType(const llvm::opt::ArgList &Args) const override;
+  UnwindTableLevel
+  getDefaultUnwindTableLevel(const llvm::opt::ArgList &Args) const override;
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;

diff  --git a/clang/test/Driver/riscv-features.c b/clang/test/Driver/riscv-features.c
index a108383e29fb6b..fc5fb0f27e3af4 100644
--- a/clang/test/Driver/riscv-features.c
+++ b/clang/test/Driver/riscv-features.c
@@ -41,6 +41,14 @@
 // FAST-UNALIGNED-ACCESS: "-target-feature" "+fast-unaligned-access"
 // NO-FAST-UNALIGNED-ACCESS: "-target-feature" "-fast-unaligned-access"
 
+// RUN: %clang --target=riscv32-unknown-elf --gcc-toolchain="" -### %s 2>&1 | FileCheck %s -check-prefix=NOUWTABLE
+// RUN: %clang --target=riscv32-unknown-elf --gcc-toolchain="" -fasynchronous-unwind-tables -### %s 2>&1 | FileCheck %s -check-prefix=UWTABLE
+// RUN: %clang --target=riscv64-unknown-elf --gcc-toolchain="" -### %s 2>&1 | FileCheck %s -check-prefix=NOUWTABLE
+// RUN: %clang --target=riscv64-unknown-elf --gcc-toolchain="" -fasynchronous-unwind-tables -### %s 2>&1 | FileCheck %s -check-prefix=UWTABLE
+//
+// UWTABLE: "-funwind-tables=2"
+// NOUWTABLE-NOT: "-funwind-tables=2"
+
 // RUN: %clang --target=riscv32-linux -### %s -fsyntax-only 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=DEFAULT-LINUX
 // RUN: %clang --target=riscv64-linux -### %s -fsyntax-only 2>&1 \