Merge r278393 and r278395.

LLVM/Clang 3.8 is directly usable as a cross compiler for CloudABI/i686.
In 3.9rc1 there are a couple of regressions in the driver that cause it
to be less usable:

- PIE was enabled unconditionally, even though it's only available for
  x86-64 and aarch64.
- Some inline assembly fails to build, due to a shortage of registers,
  as frame pointers are not omitted.

Both these changes are fairly low risk (read: they don't affect other
targets), so go ahead and merge them into 3.9, so we can use an
unmodified compiler on all architectures.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_39@278605 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 47 insertions, 12 deletions

diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 4ecbf2bac3..9bb7a59adc 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -3281,6 +3281,19 @@ Tool *CloudABI::buildLinker() const {
   return new tools::cloudabi::Linker(*this);
 }
 
+bool CloudABI::isPIEDefault() const {
+  // Only enable PIE on architectures that support PC-relative
+  // addressing. PC-relative addressing is required, as the process
+  // startup code must be able to relocate itself.
+  switch (getTriple().getArch()) {
+  case llvm::Triple::aarch64:
+  case llvm::Triple::x86_64:
+    return true;
+  default:
+    return false;
+  }
+}
+
 SanitizerMask CloudABI::getSupportedSanitizers() const {
   SanitizerMask Res = ToolChain::getSupportedSanitizers();
   Res |= SanitizerKind::SafeStack;
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index 4e5c3f7f96..369712fa93 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -634,8 +634,7 @@ public:
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
-  bool isPIEDefault() const override { return true; }
-
+  bool isPIEDefault() const override;
   SanitizerMask getSupportedSanitizers() const override;
   SanitizerMask getDefaultSanitizers() const override;
 
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index ce4c1dc0f2..31d4360184 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -3258,7 +3258,7 @@ static bool shouldUseFramePointerForTarget(const ArgList &Args,
     break;
   }
 
-  if (Triple.isOSLinux()) {
+  if (Triple.isOSLinux() || Triple.getOS() == llvm::Triple::CloudABI) {
     switch (Triple.getArch()) {
     // Don't use a frame pointer on linux if optimizing for certain targets.
     case llvm::Triple::mips64:
@@ -7458,11 +7458,13 @@ void cloudabi::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   // CloudABI only supports static linkage.
   CmdArgs.push_back("-Bstatic");
-
-  // CloudABI uses Position Independent Executables exclusively.
-  CmdArgs.push_back("-pie");
   CmdArgs.push_back("--no-dynamic-linker");
-  CmdArgs.push_back("-zrelro");
+
+  // Provide PIE linker flags in case PIE is default for the architecture.
+  if (ToolChain.isPIEDefault()) {
+    CmdArgs.push_back("-pie");
+    CmdArgs.push_back("-zrelro");
+  }
 
   CmdArgs.push_back("--eh-frame-hdr");
   CmdArgs.push_back("--gc-sections");
diff --git a/test/Driver/cloudabi.c b/test/Driver/cloudabi.c
index 7a72f61895..053092a53d 100644
--- a/test/Driver/cloudabi.c
+++ b/test/Driver/cloudabi.c
@@ -1,8 +1,14 @@
 // RUN: %clang %s -### -target x86_64-unknown-cloudabi 2>&1 | FileCheck %s -check-prefix=SAFESTACK
 // SAFESTACK: "-cc1" "-triple" "x86_64-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections" {{.*}} "-fsanitize=safe-stack"
-// SAFESTACK: "-Bstatic" "-pie" "--no-dynamic-linker" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
+// SAFESTACK: "-Bstatic" "--no-dynamic-linker" "-pie" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
 
 // RUN: %clang %s -### -target x86_64-unknown-cloudabi -fno-sanitize=safe-stack 2>&1 | FileCheck %s -check-prefix=NOSAFESTACK
 // NOSAFESTACK: "-cc1" "-triple" "x86_64-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections"
 // NOSAFESTACK-NOT: "-fsanitize=safe-stack"
-// NOSAFESTACK: "-Bstatic" "-pie" "--no-dynamic-linker" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
+// NOSAFESTACK: "-Bstatic" "--no-dynamic-linker" "-pie" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
+
+// PIE shouldn't be enabled on i686. Just on architectures that provide
+// PC-relative addressing.
+// RUN: %clang %s -### -target i686-unknown-cloudabi 2>&1 | FileCheck %s -check-prefix=NOPIE
+// NOPIE: "-cc1" "-triple" "i686-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections" {{.*}} "-fsanitize=safe-stack"
+// NOPIE: "-Bstatic" "--no-dynamic-linker" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
diff --git a/test/Driver/cloudabi.cpp b/test/Driver/cloudabi.cpp
index dd52ac36ac..f9e9ba5cb4 100644
--- a/test/Driver/cloudabi.cpp
+++ b/test/Driver/cloudabi.cpp
@@ -1,8 +1,14 @@
 // RUN: %clangxx %s -### -target x86_64-unknown-cloudabi 2>&1 | FileCheck %s -check-prefix=SAFESTACK
 // SAFESTACK: "-cc1" "-triple" "x86_64-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections" {{.*}} "-fsanitize=safe-stack"
-// SAFESTACK: "-Bstatic" "-pie" "--no-dynamic-linker" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
+// SAFESTACK: "-Bstatic" "--no-dynamic-linker" "-pie" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
 
-// RUN: %clangxx %s -### -target x86_64-unknown-cloudabi -fno-sanitize=safe-stack 2>&1 | FileCheck %s -check-prefix=NOSAFESTACk
+// RUN: %clangxx %s -### -target x86_64-unknown-cloudabi -fno-sanitize=safe-stack 2>&1 | FileCheck %s -check-prefix=NOSAFESTACK
 // NOSAFESTACK: "-cc1" "-triple" "x86_64-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections"
 // NOSAFESTACK-NOT: "-fsanitize=safe-stack"
-// NOSAFESTACk: "-Bstatic" "-pie" "--no-dynamic-linker" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
+// NOSAFESTACK: "-Bstatic" "--no-dynamic-linker" "-pie" "-zrelro" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
+
+// PIE shouldn't be enabled on i686. Just on architectures that provide
+// PC-relative addressing.
+// RUN: %clangxx %s -### -target i686-unknown-cloudabi 2>&1 | FileCheck %s -check-prefix=NOPIE
+// NOPIE: "-cc1" "-triple" "i686-unknown-cloudabi" {{.*}} "-ffunction-sections" "-fdata-sections" {{.*}} "-fsanitize=safe-stack"
+// NOPIE: "-Bstatic" "--no-dynamic-linker" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
diff --git a/test/Driver/frame-pointer-elim.c b/test/Driver/frame-pointer-elim.c
index 5355cbe3a3..139c0ccb95 100644
--- a/test/Driver/frame-pointer-elim.c
+++ b/test/Driver/frame-pointer-elim.c
@@ -8,6 +8,15 @@
 // RUN:   FileCheck --check-prefix=LINUX %s
 // LINUX-NOT: "-momit-leaf-frame-pointer"
 
+// CloudABI follows the same rules as Linux.
+// RUN: %clang -### -target x86_64-unknown-cloudabi -S -O1 %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=CLOUDABI-OPT %s
+// CLOUDABI-OPT: "-momit-leaf-frame-pointer"
+
+// RUN: %clang -### -target x86_64-unknown-cloudabi -S %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=CLOUDABI %s
+// CLOUDABI-NOT: "-momit-leaf-frame-pointer"
+
 // Darwin disables omitting the leaf frame pointer even under optimization
 // unless the command lines are given.
 // RUN: %clang -### -target i386-apple-darwin -S %s 2>&1 | \