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authorChandler Carruth <chandlerc@gmail.com>2012-04-08 17:51:45 +0000
committerChandler Carruth <chandlerc@gmail.com>2012-04-08 17:51:45 +0000
commit253933ee9ef2c413ecd782efeacc5d7b9bcda09a (patch)
tree4dd402f01a78ae40c9d6569bc5fba37f5af64501 /tools/llc
parent34797136cb9fa9f450c0e1c47983482083979dd4 (diff)
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Teach LLVM about a PIE option which, when enabled on top of PIC, makes
optimizations which are valid for position independent code being linked into a single executable, but not for such code being linked into a shared library. I discussed the design of this with Eric Christopher, and the decision was to support an optional bit rather than a completely separate relocation model. Fundamentally, this is still PIC relocation, its just that certain optimizations are only valid under a PIC relocation model when the resulting code won't be in a shared library. The simplest path to here is to expose a single bit option in the TargetOptions. If folks have different/better designs, I'm all ears. =] I've included the first optimization based upon this: changing TLS models to the *Exec models when PIE is enabled. This is the LLVM component of PR12380 and is all of the hard work. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154294 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'tools/llc')
-rw-r--r--tools/llc/llc.cpp6
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/llc/llc.cpp b/tools/llc/llc.cpp
index 191b649c05..9e30ac198b 100644
--- a/tools/llc/llc.cpp
+++ b/tools/llc/llc.cpp
@@ -263,6 +263,11 @@ TrapFuncName("trap-func", cl::Hidden,
cl::init(""));
static cl::opt<bool>
+EnablePIE("enable-pie",
+ cl::desc("Assume the creation of a position independent executable."),
+ cl::init(false));
+
+static cl::opt<bool>
SegmentedStacks("segmented-stacks",
cl::desc("Use segmented stacks if possible."),
cl::init(false));
@@ -467,6 +472,7 @@ int main(int argc, char **argv) {
Options.RealignStack = EnableRealignStack;
Options.DisableJumpTables = DisableSwitchTables;
Options.TrapFuncName = TrapFuncName;
+ Options.PositionIndependentExecutable = EnablePIE;
Options.EnableSegmentedStacks = SegmentedStacks;
std::auto_ptr<TargetMachine>