silence symbol overrides

Linker produces warnings for symbol overrides from linker script.

Notify the user with -Wlinker-script, instead of producing this warning by
default.

Several users build images using --fatal-warnings, and these warnings prevent
the build from being succesful.

Fixes (qualcomm#145)

Change-Id: I2336ffc93859040daa18f3f2630fca3dea63a3f0
Signed-off-by: Shankar Easwaran <[email protected]>

Author: quic-seaswara

lib/SymbolResolver/IRBuilder.cpp

@@ -515,7 +515,7 @@ LDSymbol *IRBuilder::addSymbol<IRBuilder::Force, IRBuilder::Unresolve>(
   } else {
     // the symbol is already in the pool, override it
     ResolveInfo OldInfo;
-    if (!Info->isUndef())
+    if (ThisConfig.showLinkerScriptWarnings() && !Info->isUndef())
       ThisConfig.raise(Diag::warning_override_symbol)
           << SymbolName << Input->getInput()->decoratedPath()
           << Info->getResolvedPath();

test/Common/standalone/MultipleDefinitions/MultipleDefinitions.test

@@ -12,22 +12,22 @@ RUN: %clang %clangopts -o %t1.2.o -c %p/Inputs/2.c -ffunction-sections
 # Override symbols Defsym expressions
 #
 RUN: %clang %clangopts -o %t1.1.o -c %p/Inputs/1.c -ffunction-sections
-RUN: %link %linkopts %t1.1.o --defsym v=200 -o %t2.out 2>&1 | %filecheck %s -check-prefix=WARNDEF
+RUN: %link %linkopts -Wlinker-script %t1.1.o --defsym v=200 -o %t2.out 2>&1 | %filecheck %s -check-prefix=WARNDEF
 #WARNDEF: Warning: Symbol v defined in Expression(Defsym)v=200 overrides symbol in
 
 #
 # Check that linker script assignments are processed in link order
 #
-RUN: %link %linkopts %t1.1.o --defsym v=100 -o %t2.out.2 -T %p/Inputs/s.t 2>&1 | %filecheck %s -check-prefix=DEFSYMSCRIPT
-RUN: %link %linkopts %t1.1.o --defsym v=100 -o %t2.out.3 %p/Inputs/s.t 2>&1 | %filecheck %s -check-prefix=DEFSYMSCRIPT
+RUN: %link %linkopts -Wlinker-script %t1.1.o --defsym v=100 -o %t2.out.2 -T %p/Inputs/s.t 2>&1 | %filecheck %s -check-prefix=DEFSYMSCRIPT
+RUN: %link %linkopts -Wlinker-script %t1.1.o --defsym v=100 -o %t2.out.3 %p/Inputs/s.t 2>&1 | %filecheck %s -check-prefix=DEFSYMSCRIPT
 #DEFSYMSCRIPT: Warning: Symbol v defined in Expression(Defsym)v=100 overrides symbol in {{.*}}1.o
 
 
 #
 # Check that linker script assignment definitions are processed after all object
 # files are processed
 #
-RUN: %not %link %linkopts %t1.1.o --defsym v=100 -T %p/Inputs/s.t %t1.2.o 2>&1 | %filecheck %s -check-prefix=MULDEF
+RUN: %not %link %linkopts -Wlinker-script %t1.1.o --defsym v=100 -T %p/Inputs/s.t %t1.2.o 2>&1 | %filecheck %s -check-prefix=MULDEF
 #MULDEF: Error: multiple definition of symbol `v' in file {{.*}}1.o and {{.*}}2.o
 
 #END_TEST