Enable PIE for CloudABI.

As we're currently working on making CloudABI executables easier to
emulate in userspace (e.g., on OS X and Windows), it makes a whole lot
of sense to build these using PIE. By using PIE, they can simply be
loaded into the existing process address space without clashes.

PIE support got added to CloudABI's C library and seems to work pretty
well. CloudABI does not make use of an ld.so, so the binary's _start()
has all the logic in it to do the relocations.

Now that all but one bug in LLD relating to PIE support have been
squashed (and a patch for that is already in code review), I'd like to
go ahead and force the use of PIE for Clang 3.9. When released, we'll
also switch over to using LLD exclusively.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@265546 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index d0418349bfa3c63ad5e0fad7550499e21fa14d79..e7992170cc8a05ffba044dce8d09cda9c8e24ac6 100644 (file)
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -617,7 +617,7 @@ public:
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
-  bool isPIEDefault() const override { return false; }
+  bool isPIEDefault() const override { return true; }
 
   SanitizerMask getSupportedSanitizers() const override;
   SanitizerMask getDefaultSanitizers() const override;

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 6be28290a7fbdbd53bd3fb19693646832aa20771..a585918aa28bdefe0d366180d2adba1736e7d129 100644 (file)
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -7110,6 +7110,12 @@ 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");
+
   CmdArgs.push_back("--eh-frame-hdr");
   CmdArgs.push_back("--gc-sections");
 

diff --git a/test/Driver/cloudabi.c b/test/Driver/cloudabi.c
index 2f1f9852b0a671b2902fc65597f0347563dae747..7a72f6189515bfe1094434d9dfa7682821f832f4 100644 (file)
--- a/test/Driver/cloudabi.c
+++ b/test/Driver/cloudabi.c
@@ -1,8 +1,8 @@
 // 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" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
+// SAFESTACK: "-Bstatic" "-pie" "--no-dynamic-linker" "-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" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc" "-lcompiler_rt" "crtend.o"
+// NOSAFESTACK: "-Bstatic" "-pie" "--no-dynamic-linker" "-zrelro" "--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 9c1b6d091c19c0e8b695185e8e1fc2e07b5943ae..dd52ac36acc81cfd7d8e9b81e1ee364242ff9dac 100644 (file)
--- a/test/Driver/cloudabi.cpp
+++ b/test/Driver/cloudabi.cpp
@@ -1,8 +1,8 @@
 // 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" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
+// 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"
 
 // 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" "--eh-frame-hdr" "--gc-sections" "-o" "a.out" "crt0.o" "crtbegin.o" "{{.*}}" "{{.*}}" "-lc++" "-lc++abi" "-lunwind" "-lc" "-lcompiler_rt" "crtend.o"
+// 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"