[AIX][TLS][clang] Add -maix-small-local-dynamic-tls clang option (#88829

)

This patch adds the clang portion of an AIX-specific option to inform
the
compiler that it can use a faster access sequence for the local-dynamic
TLS model (formally named aix-small-local-dynamic-tls).

This patch mainly references Amy's work on small local-exec TLS support.

clang/docs/ReleaseNotes.rst

@@ -659,6 +659,12 @@ CUDA Support
 AIX Support
 ^^^^^^^^^^^
 
+- Introduced the ``-maix-small-local-dynamic-tls`` option to produce a faster
+  access sequence for local-dynamic TLS variables where the offset from the TLS
+  base is encoded as an immediate operand.
+  This access sequence is not used for TLS variables larger than 32KB, and is
+  currently only supported on 64-bit mode.
+
 WebAssembly Support
 ^^^^^^^^^^^^^^^^^^^
 

clang/include/clang/Driver/Options.td

@@ -5041,6 +5041,12 @@ def maix_small_local_exec_tls : Flag<["-"], "maix-small-local-exec-tls">,
            "where the offset from the TLS base is encoded as an "
            "immediate operand (AIX 64-bit only). "
            "This access sequence is not used for variables larger than 32KB.">;
+def maix_small_local_dynamic_tls : Flag<["-"], "maix-small-local-dynamic-tls">,
+  Group<m_ppc_Features_Group>,
+  HelpText<"Produce a faster access sequence for local-dynamic TLS variables "
+           "where the offset from the TLS base is encoded as an "
+           "immediate operand (AIX 64-bit only). "
+           "This access sequence is not used for variables larger than 32KB.">;
 def maix_struct_return : Flag<["-"], "maix-struct-return">,
   Group<m_Group>, Visibility<[ClangOption, CC1Option]>,
   HelpText<"Return all structs in memory (PPC32 only)">,

clang/lib/Basic/Targets/PPC.cpp

@@ -79,6 +79,8 @@ bool PPCTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasPrivileged = true;
     } else if (Feature == "+aix-small-local-exec-tls") {
       HasAIXSmallLocalExecTLS = true;
+    } else if (Feature == "+aix-small-local-dynamic-tls") {
+      HasAIXSmallLocalDynamicTLS = true;
     } else if (Feature == "+isa-v206-instructions") {
       IsISA2_06 = true;
     } else if (Feature == "+isa-v207-instructions") {
@@ -573,9 +575,10 @@ bool PPCTargetInfo::initFeatureMap(
   // Privileged instructions are off by default.
   Features["privileged"] = false;
 
-  // The code generated by the -maix-small-local-exec-tls option is turned
-  // off by default.
+  // The code generated by the -maix-small-local-[exec|dynamic]-tls option is
+  // turned off by default.
   Features["aix-small-local-exec-tls"] = false;
+  Features["aix-small-local-dynamic-tls"] = false;
 
   Features["spe"] = llvm::StringSwitch<bool>(CPU)
                         .Case("8548", true)
@@ -713,6 +716,7 @@ bool PPCTargetInfo::hasFeature(StringRef Feature) const {
       .Case("rop-protect", HasROPProtect)
       .Case("privileged", HasPrivileged)
       .Case("aix-small-local-exec-tls", HasAIXSmallLocalExecTLS)
+      .Case("aix-small-local-dynamic-tls", HasAIXSmallLocalDynamicTLS)
       .Case("isa-v206-instructions", IsISA2_06)
       .Case("isa-v207-instructions", IsISA2_07)
       .Case("isa-v30-instructions", IsISA3_0)

clang/lib/Basic/Targets/PPC.h

@@ -61,6 +61,7 @@ class LLVM_LIBRARY_VISIBILITY PPCTargetInfo : public TargetInfo {
   bool HasROPProtect = false;
   bool HasPrivileged = false;
   bool HasAIXSmallLocalExecTLS = false;
+  bool HasAIXSmallLocalDynamicTLS = false;
   bool HasVSX = false;
   bool UseCRBits = false;
   bool HasP8Vector = false;

clang/lib/Driver/ToolChains/Arch/PPC.cpp

@@ -125,21 +125,22 @@ void ppc::getPPCTargetFeatures(const Driver &D, const llvm::Triple &Triple,
 
   bool UseSeparateSections = isUseSeparateSections(Triple);
   bool HasDefaultDataSections = Triple.isOSBinFormatXCOFF();
-  if (Args.hasArg(options::OPT_maix_small_local_exec_tls)) {
+  if (Args.hasArg(options::OPT_maix_small_local_exec_tls) ||
+      Args.hasArg(options::OPT_maix_small_local_dynamic_tls)) {
     if (!Triple.isOSAIX() || !Triple.isArch64Bit())
-      D.Diag(diag::err_opt_not_valid_on_target) << "-maix-small-local-exec-tls";
+      D.Diag(diag::err_opt_not_valid_on_target)
+          << "-maix-small-local-[exec|dynamic]-tls";
 
-    // The -maix-small-local-exec-tls option should only be used with
+    // The -maix-small-local-[exec|dynamic]-tls option should only be used with
     // -fdata-sections, as having data sections turned off with this option
-    // is not ideal for performance. Moreover, the small-local-exec-tls region
-    // is a limited resource, and should not be used for variables that may
-    // be replaced.
+    // is not ideal for performance. Moreover, the
+    // small-local-[exec|dynamic]-tls region is a limited resource, and should
+    // not be used for variables that may be replaced.
     if (!Args.hasFlag(options::OPT_fdata_sections,
                       options::OPT_fno_data_sections,
                       UseSeparateSections || HasDefaultDataSections))
       D.Diag(diag::err_drv_argument_only_allowed_with)
-          << "-maix-small-local-exec-tls"
-          << "-fdata-sections";
+          << "-maix-small-local-[exec|dynamic]-tls" << "-fdata-sections";
   }
 }
 

clang/test/Driver/aix-small-local-exec-tls.c → clang/test/Driver/aix-small-local-exec-dynamic-tls.c

@@ -6,6 +6,9 @@
 // RUN: %clang -target powerpc64-unknown-aix -maix-small-local-exec-tls -S -emit-llvm \
 // RUN:    %s -o - | FileCheck %s --check-prefix=CHECK-AIX_SMALL_LOCALEXEC_TLS
 
+// RUN: %clang -target powerpc64-unknown-aix -maix-small-local-dynamic-tls -S -emit-llvm \
+// RUN:    %s -o - | FileCheck %s --check-prefix=CHECK-AIX_SMALL_LOCALDYNAMIC_TLS
+
 // RUN: not %clang -target powerpc-unknown-aix -maix-small-local-exec-tls \
 // RUN:    -fsyntax-only %s 2>&1 | FileCheck --check-prefix=CHECK-UNSUPPORTED-AIX32 %s
 // RUN: not %clang -target powerpc64le-unknown-linux-gnu -maix-small-local-exec-tls \
@@ -19,19 +22,35 @@
 // RUN:    -fsyntax-only -fno-data-sections %s 2>&1 | \
 // RUN:    FileCheck --check-prefix=CHECK-UNSUPPORTED-NO-DATASEC %s
 
+// RUN: not %clang -target powerpc-unknown-aix -maix-small-local-dynamic-tls \
+// RUN:    -fsyntax-only %s 2>&1 | FileCheck --check-prefix=CHECK-UNSUPPORTED-AIX32 %s
+// RUN: not %clang -target powerpc64le-unknown-linux-gnu -maix-small-local-dynamic-tls \
+// RUN:    -fsyntax-only %s 2>&1 | FileCheck --check-prefix=CHECK-UNSUPPORTED-LINUX %s
+// RUN: not %clang -target powerpc64-unknown-linux-gnu -maix-small-local-dynamic-tls \
+// RUN:    -fsyntax-only %s 2>&1 | FileCheck --check-prefix=CHECK-UNSUPPORTED-LINUX %s
+// RUN: not %clang -target powerpc64-unknown-aix -maix-small-local-dynamic-tls \
+// RUN:    -fsyntax-only -fno-data-sections %s 2>&1 | \
+// RUN:    FileCheck --check-prefix=CHECK-UNSUPPORTED-NO-DATASEC %s
+// RUN: not %clang -target powerpc64-unknown-linux-gnu -maix-small-local-dynamic-tls \
+// RUN:    -fsyntax-only -fno-data-sections %s 2>&1 | \
+// RUN:    FileCheck --check-prefix=CHECK-UNSUPPORTED-NO-DATASEC %s
+
 int test(void) {
   return 0;
 }
 
 // CHECK: test() #0 {
 // CHECK: attributes #0 = {
-// CHECK-SAME: -aix-small-local-exec-tls
+// CHECK-SAME: {{-aix-small-local-exec-tls,.*-aix-small-local-dynamic-tls|-aix-small-local-dynamic-tls,.*-aix-small-local-exec-tls}}
 
-// CHECK-UNSUPPORTED-AIX32: option '-maix-small-local-exec-tls' cannot be specified on this target
-// CHECK-UNSUPPORTED-LINUX: option '-maix-small-local-exec-tls' cannot be specified on this target
-// CHECK-UNSUPPORTED-NO-DATASEC: invalid argument '-maix-small-local-exec-tls' only allowed with '-fdata-sections'
+// CHECK-UNSUPPORTED-AIX32: option '-maix-small-local-[exec|dynamic]-tls' cannot be specified on this target
+// CHECK-UNSUPPORTED-LINUX: option '-maix-small-local-[exec|dynamic]-tls' cannot be specified on this target
+// CHECK-UNSUPPORTED-NO-DATASEC: invalid argument '-maix-small-local-[exec|dynamic]-tls' only allowed with '-fdata-sections'
 
 // CHECK-AIX_SMALL_LOCALEXEC_TLS: test() #0 {
 // CHECK-AIX_SMALL_LOCALEXEC_TLS: attributes #0 = {
 // CHECK-AIX_SMALL_LOCALEXEC_TLS-SAME: +aix-small-local-exec-tls
 
+// CHECK-AIX_SMALL_LOCALDYNAMIC_TLS: test() #0 {
+// CHECK-AIX_SMALL_LOCALDYNAMIC_TLS: attributes #0 = {
+// CHECK-AIX_SMALL_LOCALDYNAMIC_TLS-SAME: +aix-small-local-dynamic-tls