[clang] [llvm] [Driver] Default -msmall-data-limit= to 0 and clean up code (PR #83093)

[Fangrui Song via cfe-commits]

https://github.com/MaskRay updated https://github.com/llvm/llvm-project/pull/83093

>From dbc9ddd9a9b1b73d56f8aab5265db36a44e6fcaf Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Mon, 26 Feb 2024 17:58:55 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.4
---
 clang/lib/Driver/ToolChains/Clang.cpp         | 41 ++-----------------
 .../CodeGen/RISCV/riscv-sdata-module-flag.c   |  4 +-
 clang/test/Driver/riscv-sdata-warning.c       |  4 --
 clang/test/Driver/riscv-sdata.c               |  5 +++
 llvm/lib/Target/RISCV/RISCVTargetObjectFile.h |  2 +-
 5 files changed, 12 insertions(+), 44 deletions(-)
 delete mode 100644 clang/test/Driver/riscv-sdata-warning.c
 create mode 100644 clang/test/Driver/riscv-sdata.c

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 6e1b7e8657d0dc..9b9eab3990607f 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2029,42 +2029,6 @@ void Clang::AddPPCTargetArgs(const ArgList &Args,
   }
 }
 
-static void SetRISCVSmallDataLimit(const ToolChain &TC, const ArgList &Args,
-                                   ArgStringList &CmdArgs) {
-  const Driver &D = TC.getDriver();
-  const llvm::Triple &Triple = TC.getTriple();
-  // Default small data limitation is eight.
-  const char *SmallDataLimit = "8";
-  // Get small data limitation.
-  if (Args.getLastArg(options::OPT_shared, options::OPT_fpic,
-                      options::OPT_fPIC)) {
-    // Not support linker relaxation for PIC.
-    SmallDataLimit = "0";
-    if (Args.hasArg(options::OPT_G)) {
-      D.Diag(diag::warn_drv_unsupported_sdata);
-    }
-  } else if (Args.getLastArgValue(options::OPT_mcmodel_EQ)
-                 .equals_insensitive("large") &&
-             (Triple.getArch() == llvm::Triple::riscv64)) {
-    // Not support linker relaxation for RV64 with large code model.
-    SmallDataLimit = "0";
-    if (Args.hasArg(options::OPT_G)) {
-      D.Diag(diag::warn_drv_unsupported_sdata);
-    }
-  } else if (Triple.isAndroid()) {
-    // GP relaxation is not supported on Android.
-    SmallDataLimit = "0";
-    if (Args.hasArg(options::OPT_G)) {
-      D.Diag(diag::warn_drv_unsupported_sdata);
-    }
-  } else if (Arg *A = Args.getLastArg(options::OPT_G)) {
-    SmallDataLimit = A->getValue();
-  }
-  // Forward the -msmall-data-limit= option.
-  CmdArgs.push_back("-msmall-data-limit");
-  CmdArgs.push_back(SmallDataLimit);
-}
-
 void Clang::AddRISCVTargetArgs(const ArgList &Args,
                                ArgStringList &CmdArgs) const {
   const llvm::Triple &Triple = getToolChain().getTriple();
@@ -2073,7 +2037,10 @@ void Clang::AddRISCVTargetArgs(const ArgList &Args,
   CmdArgs.push_back("-target-abi");
   CmdArgs.push_back(ABIName.data());
 
-  SetRISCVSmallDataLimit(getToolChain(), Args, CmdArgs);
+  if (Arg *A = Args.getLastArg(options::OPT_G)) {
+    CmdArgs.push_back("-msmall-data-limit");
+    CmdArgs.push_back(A->getValue());
+  }
 
   if (!Args.hasFlag(options::OPT_mimplicit_float,
                     options::OPT_mno_implicit_float, true))
diff --git a/clang/test/CodeGen/RISCV/riscv-sdata-module-flag.c b/clang/test/CodeGen/RISCV/riscv-sdata-module-flag.c
index 9bd69e7995877e..e91b2e7f225f52 100644
--- a/clang/test/CodeGen/RISCV/riscv-sdata-module-flag.c
+++ b/clang/test/CodeGen/RISCV/riscv-sdata-module-flag.c
@@ -30,14 +30,14 @@
 
 void test(void) {}
 
-// RV32-DEFAULT: !{i32 8, !"SmallDataLimit", i32 8}
+// RV32-DEFAULT: !{i32 8, !"SmallDataLimit", i32 0}
 // RV32-G4:      !{i32 8, !"SmallDataLimit", i32 4}
 // RV32-S0:      !{i32 8, !"SmallDataLimit", i32 0}
 // RV32-S2G4:    !{i32 8, !"SmallDataLimit", i32 4}
 // RV32-T16:     !{i32 8, !"SmallDataLimit", i32 16}
 // RV32-PIC:     !{i32 8, !"SmallDataLimit", i32 0}
 
-// RV64-DEFAULT: !{i32 8, !"SmallDataLimit", i32 8}
+// RV64-DEFAULT: !{i32 8, !"SmallDataLimit", i32 0}
 // RV64-G4:      !{i32 8, !"SmallDataLimit", i32 4}
 // RV64-S0:      !{i32 8, !"SmallDataLimit", i32 0}
 // RV64-S2G4:    !{i32 8, !"SmallDataLimit", i32 4}
diff --git a/clang/test/Driver/riscv-sdata-warning.c b/clang/test/Driver/riscv-sdata-warning.c
deleted file mode 100644
index ace9a32ee116fd..00000000000000
--- a/clang/test/Driver/riscv-sdata-warning.c
+++ /dev/null
@@ -1,4 +0,0 @@
-// REQUIRES: riscv-registered-target
-// RUN: %clang -S --target=riscv32-unknown-elf -fpic -msmall-data-limit=8 %s 2>&1 \
-// RUN:   | FileCheck -check-prefix=CHECK-PIC-SDATA %s
-// CHECK-PIC-SDATA: warning: ignoring '-msmall-data-limit=' with -mcmodel=large for -fpic or RV64
diff --git a/clang/test/Driver/riscv-sdata.c b/clang/test/Driver/riscv-sdata.c
new file mode 100644
index 00000000000000..84cd109813db4c
--- /dev/null
+++ b/clang/test/Driver/riscv-sdata.c
@@ -0,0 +1,5 @@
+// RUN: %clang -### -S --target=riscv64 %s 2>&1 | FileCheck %s
+// RUN: %clang -### -S --target=riscv64 -msmall-data-limit=8 %s 2>&1 | FileCheck %s --check-prefix=EIGHT
+
+// CHECK-NOT: "-msmall-data-limit"
+// EIGHT: "-msmall-data-limit" "8"
diff --git a/llvm/lib/Target/RISCV/RISCVTargetObjectFile.h b/llvm/lib/Target/RISCV/RISCVTargetObjectFile.h
index 0910fbd3d95041..2d4fa211fa303e 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetObjectFile.h
+++ b/llvm/lib/Target/RISCV/RISCVTargetObjectFile.h
@@ -17,7 +17,7 @@ namespace llvm {
 class RISCVELFTargetObjectFile : public TargetLoweringObjectFileELF {
   MCSection *SmallDataSection;
   MCSection *SmallBSSSection;
-  unsigned SSThreshold = 8;
+  unsigned SSThreshold = 0;
 
 public:
   unsigned getTextSectionAlignment() const override;