Add -fapply-global-visibility-to-externs for -cc1

Introduce an option to request global visibility settings be applied to
declarations without a definition or an explicit visibility, rather than
the existing behavior of giving these default visibility. When the
visibility of all or most extern definitions are known this allows for
the same optimisations -fvisibility permits without updating source code
to annotate all declarations.

Differential Revision: https://reviews.llvm.org/D56868

llvm-svn: 352391

diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 36d3764..4e391d2 100644 (file)
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -261,6 +261,8 @@ ENUM_LANGOPT(ValueVisibilityMode, Visibility, 3, DefaultVisibility,
              "default visibility for functions and variables [-fvisibility]")
 ENUM_LANGOPT(TypeVisibilityMode, Visibility, 3, DefaultVisibility,
              "default visibility for types [-ftype-visibility]")
+LANGOPT(SetVisibilityForExternDecls, 1, 0,
+        "apply global symbol visibility to external declarations without an explicit visibility")
 ENUM_LANGOPT(StackProtector, StackProtectorMode, 2, SSPOff,
              "stack protector mode")
 ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKind::Uninitialized,

diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 4cce9e6..cead872 100644 (file)
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -702,6 +702,8 @@ def fvisibility : Separate<["-"], "fvisibility">,
   HelpText<"Default type and symbol visibility">;
 def ftype_visibility : Separate<["-"], "ftype-visibility">,
   HelpText<"Default type visibility">;
+def fapply_global_visibility_to_externs : Flag<["-"], "fapply-global-visibility-to-externs">,
+  HelpText<"Apply global symbol visibility to external declarations without an explicit visibility">;
 def ftemplate_depth : Separate<["-"], "ftemplate-depth">,
   HelpText<"Maximum depth of recursive template instantiation">;
 def foperator_arrow_depth : Separate<["-"], "foperator-arrow-depth">,

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 0be4bad..5a1b7cf 100644 (file)
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -731,9 +731,11 @@ void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
   }
   if (!D)
     return;
-  // Set visibility for definitions.
+  // Set visibility for definitions, and for declarations if requested globally
+  // or set explicitly.
   LinkageInfo LV = D->getLinkageAndVisibility();
-  if (LV.isVisibilityExplicit() || !GV->isDeclarationForLinker())
+  if (LV.isVisibilityExplicit() || getLangOpts().SetVisibilityForExternDecls ||
+      !GV->isDeclarationForLinker())
     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
 }
 

diff --git a/clang/lib/Driver/ToolChains/AMDGPU.cpp b/clang/lib/Driver/ToolChains/AMDGPU.cpp
index a03a607..b9300bc 100644 (file)
--- a/clang/lib/Driver/ToolChains/AMDGPU.cpp
+++ b/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -108,5 +108,6 @@ void AMDGPUToolChain::addClangTargetOptions(
                          options::OPT_fvisibility_ms_compat)) {
     CC1Args.push_back("-fvisibility");
     CC1Args.push_back("hidden");
+    CC1Args.push_back("-fapply-global-visibility-to-externs");
   }
 }

diff --git a/clang/lib/Driver/ToolChains/HIP.cpp b/clang/lib/Driver/ToolChains/HIP.cpp
index f55dd2f..cd8ed61 100644 (file)
--- a/clang/lib/Driver/ToolChains/HIP.cpp
+++ b/clang/lib/Driver/ToolChains/HIP.cpp
@@ -293,8 +293,10 @@ void HIPToolChain::addClangTargetOptions(
   // Default to "hidden" visibility, as object level linking will not be
   // supported for the foreseeable future.
   if (!DriverArgs.hasArg(options::OPT_fvisibility_EQ,
-                         options::OPT_fvisibility_ms_compat))
+                         options::OPT_fvisibility_ms_compat)) {
     CC1Args.append({"-fvisibility", "hidden"});
+    CC1Args.push_back("-fapply-global-visibility-to-externs");
+  }
 }
 
 llvm::opt::DerivedArgList *

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 4d72924..dbc29e2 100644 (file)
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2501,6 +2501,9 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   if (Args.hasArg(OPT_fvisibility_global_new_delete_hidden))
     Opts.GlobalAllocationFunctionVisibilityHidden = 1;
 
+  if (Args.hasArg(OPT_fapply_global_visibility_to_externs))
+    Opts.SetVisibilityForExternDecls = 1;
+
   if (Args.hasArg(OPT_ftrapv)) {
     Opts.setSignedOverflowBehavior(LangOptions::SOB_Trapping);
     // Set the handler, if one is specified.

diff --git a/clang/test/CodeGen/set-visibility-for-decls.c b/clang/test/CodeGen/set-visibility-for-decls.c
new file mode 100644 (file)
index 0000000..04232f8
--- /dev/null
+++ b/clang/test/CodeGen/set-visibility-for-decls.c
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 %s -std=c11 -triple=x86_64-pc-linux -fvisibility hidden -fapply-global-visibility-to-externs -emit-llvm -o - | FileCheck --check-prefix=CHECK-HIDDEN %s
+// RUN: %clang_cc1 %s -std=c11 -triple=x86_64-pc-linux -fvisibility protected -fapply-global-visibility-to-externs -emit-llvm -o - | FileCheck --check-prefix=CHECK-PROTECTED %s
+// RUN: %clang_cc1 %s -std=c11 -triple=x86_64-pc-linux -fvisibility default -fapply-global-visibility-to-externs -emit-llvm -o - | FileCheck --check-prefix=CHECK-DEFAULT %s
+
+// CHECK-HIDDEN: @var_hidden = external hidden global
+// CHECK-PROTECTED: @var_hidden = external hidden global
+// CHECK-DEFAULT: @var_hidden = external hidden global
+__attribute__((visibility("hidden"))) extern int var_hidden;
+// CHECK-HIDDEN: @var_protected = external protected global
+// CHECK-PROTECTED: @var_protected = external protected global
+// CHECK-DEFAULT: @var_protected = external protected global
+__attribute__((visibility("protected"))) extern int var_protected;
+// CHECK-HIDDEN: @var_default = external global
+// CHECK-PROTECTED: @var_default = external global
+// CHECK-DEFAULT: @var_default = external global
+__attribute__((visibility("default"))) extern int var_default;
+// CHECK-HIDDEN: @var = external hidden global
+// CHECK-PROTECTED: @var = external protected global
+// CHECK-DEFAULT: @var = external global
+extern int var;
+
+// CHECK-HIDDEN: declare hidden i32 @func_hidden()
+// CHECK-PROTECTED: declare hidden i32 @func_hidden()
+// CHECK-DEFAULT: declare hidden i32 @func_hidden()
+__attribute__((visibility("hidden"))) int func_hidden(void);
+// CHECK-HIDDEN: declare protected i32 @func_protected()
+// CHECK-PROTECTED: declare protected i32 @func_protected()
+// CHECK-DEFAULT: declare protected i32 @func_protected()
+__attribute__((visibility("protected"))) int func_protected(void);
+// CHECK-HIDDEN: declare i32 @func_default()
+// CHECK-PROTECTED: declare i32 @func_default()
+// CHECK-DEFAULT: declare i32 @func_default()
+__attribute__((visibility("default"))) int func_default(void);
+// CHECK-HIDDEN: declare hidden i32 @func()
+// CHECK-PROTECTED: declare protected i32 @func()
+// CHECK-DEFAULT: declare i32 @func()
+int func(void);
+
+int use() {
+  return var_hidden + var_protected + var_default + var +
+         func_hidden() + func_protected() + func_default() + func();
+}

diff --git a/clang/test/Driver/amdgpu-visibility.cl b/clang/test/Driver/amdgpu-visibility.cl
index 35969db..19756d4 100644 (file)
--- a/clang/test/Driver/amdgpu-visibility.cl
+++ b/clang/test/Driver/amdgpu-visibility.cl
@@ -2,6 +2,14 @@
 // RUN: %clang -### -target amdgcn-amd-amdhsa -x cl -c -emit-llvm -fvisibility=protected  %s 2>&1 | FileCheck -check-prefix=OVERRIDE-PROTECTED  %s
 // RUN: %clang -### -target amdgcn-amd-amdhsa -x cl -c -emit-llvm -fvisibility-ms-compat  %s 2>&1 | FileCheck -check-prefix=OVERRIDE-MS  %s
 
-// DEFAULT: "-fvisibility" "hidden"
+// DEFAULT-DAG: "-fvisibility" "hidden"
+// DEFAULT-DAG: "-fapply-global-visibility-to-externs"
+
+// OVERRIDE-PROTECTED-NOT: "-fapply-global-visibility-to-externs"
 // OVERRIDE-PROTECTED: "-fvisibility" "protected"
-// OVERRIDE-MS:  "-fvisibility" "hidden" "-ftype-visibility" "default"
+// OVERRIDE-PROTECTED-NOT: "-fapply-global-visibility-to-externs"
+
+// OVERRIDE-MS-NOT: "-fapply-global-visibility-to-externs"
+// OVERRIDE-MS-DAG: "-fvisibility" "hidden"
+// OVERRIDE-MS-DAG: "-ftype-visibility" "default"
+// OVERRIDE-MS-NOT: "-fapply-global-visibility-to-externs"

diff --git a/clang/test/Driver/hip-toolchain-no-rdc.hip b/clang/test/Driver/hip-toolchain-no-rdc.hip
index 4f31a39..e8e4918 100644 (file)
--- a/clang/test/Driver/hip-toolchain-no-rdc.hip
+++ b/clang/test/Driver/hip-toolchain-no-rdc.hip
@@ -20,6 +20,7 @@
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "a.cu" {{.*}} "-target-cpu" "gfx803"
 // CHECK-SAME: "-fcuda-is-device" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[A_BC_803:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[A_SRC:".*a.cu"]]
 
@@ -47,6 +48,7 @@
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "a.cu" {{.*}} "-target-cpu" "gfx900"
 // CHECK-SAME: "-fcuda-is-device" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[A_BC_900:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[A_SRC]]
 
@@ -89,6 +91,7 @@
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "b.hip" {{.*}} "-target-cpu" "gfx803"
 // CHECK-SAME: "-fcuda-is-device" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[B_BC_803:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[B_SRC:".*b.hip"]]
 
@@ -116,6 +119,7 @@
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "b.hip" {{.*}} "-target-cpu" "gfx900"
 // CHECK-SAME: "-fcuda-is-device" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[B_BC_900:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[B_SRC]]
 

diff --git a/clang/test/Driver/hip-toolchain-rdc.hip b/clang/test/Driver/hip-toolchain-rdc.hip
index 5f3fd92..dc6fc6f 100644 (file)
--- a/clang/test/Driver/hip-toolchain-rdc.hip
+++ b/clang/test/Driver/hip-toolchain-rdc.hip
@@ -12,10 +12,11 @@
 // RUN:   %S/Inputs/hip_multiple_inputs/b.hip \
 // RUN: 2>&1 | FileCheck %s
 
-// CHECK: [[CLANG:".*clang.*"]] "-cc1" "-triple" "amdgcn-amd-amdhsa" 
+// CHECK: [[CLANG:".*clang.*"]] "-cc1" "-triple" "amdgcn-amd-amdhsa"
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "a.cu" {{.*}} "-target-cpu" "gfx803"
 // CHECK-SAME: "-fcuda-is-device" "-fgpu-rdc" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[A_BC:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[A_SRC:".*a.cu"]]
 
@@ -23,6 +24,7 @@
 // CHECK-SAME: "-aux-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc"
 // CHECK-SAME: {{.*}} "-main-file-name" "b.hip" {{.*}} "-target-cpu" "gfx803"
 // CHECK-SAME: "-fcuda-is-device" "-fgpu-rdc" "-fvisibility" "hidden"
+// CHECK-SAME: "-fapply-global-visibility-to-externs"
 // CHECK-SAME: {{.*}} "-o" [[B_BC:".*bc"]] "-x" "hip"
 // CHECK-SAME: {{.*}} [[B_SRC:".*b.hip"]]