MemorySanitizer does not require PIE.

Since r249754 MemorySanitizer should work equally well for PIE and
non-PIE executables on Linux/x86_64.

Beware, with this change -fsanitize=memory no longer adds implicit
-fPIE -pie compiler/linker flags on Linux/x86_64.

This is a re-land of r250941, limited to Linux/x86_64 + a very minor
refactoring in SanitizerArgs.

llvm-svn: 250949

1 files changed, 8 insertions, 6 deletions

diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 8c417ef4324..3f1b99cac50 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -29,7 +29,7 @@ enum : SanitizerMask {
   NeedsUbsanRt = Undefined | Integer | CFI,
   NeedsUbsanCxxRt = Vptr | CFI,
   NotAllowedWithTrap = Vptr,
-  RequiresPIE = Memory | DataFlow,
+  RequiresPIE = DataFlow,
   NeedsUnwindTables = Address | Thread | Memory | DataFlow,
   SupportsCoverage = Address | Memory | Leak | Undefined | Integer | DataFlow,
   RecoverableByDefault = Undefined | Integer,
@@ -164,7 +164,7 @@ bool SanitizerArgs::needsUbsanRt() const {
 }
 
 bool SanitizerArgs::requiresPIE() const {
-  return AsanZeroBaseShadow || (Sanitizers.Mask & RequiresPIE);
+  return NeedPIE || (Sanitizers.Mask & RequiresPIE);
 }
 
 bool SanitizerArgs::needsUnwindTables() const {
@@ -180,8 +180,8 @@ void SanitizerArgs::clear() {
   CoverageFeatures = 0;
   MsanTrackOrigins = 0;
   MsanUseAfterDtor = false;
+  NeedPIE = false;
   AsanFieldPadding = 0;
-  AsanZeroBaseShadow = false;
   AsanSharedRuntime = false;
   LinkCXXRuntimes = false;
 }
@@ -424,8 +424,10 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
         }
       }
     }
-    MsanUseAfterDtor = 
-      Args.hasArg(options::OPT_fsanitize_memory_use_after_dtor);
+    MsanUseAfterDtor =
+        Args.hasArg(options::OPT_fsanitize_memory_use_after_dtor);
+    NeedPIE |= !(TC.getTriple().isOSLinux() &&
+                 TC.getTriple().getArch() == llvm::Triple::x86_64);
   }
 
   // Parse -f(no-)?sanitize-coverage flags if coverage is supported by the
@@ -496,7 +498,7 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   if (AllAddedKinds & Address) {
     AsanSharedRuntime =
         Args.hasArg(options::OPT_shared_libasan) || TC.getTriple().isAndroid();
-    AsanZeroBaseShadow = TC.getTriple().isAndroid();
+    NeedPIE |= TC.getTriple().isAndroid();
     if (Arg *A =
             Args.getLastArg(options::OPT_fsanitize_address_field_padding)) {
         StringRef S = A->getValue();