From 9cad440d4c739ccf6e524df2e3416ad07ec177a5 Mon Sep 17 00:00:00 2001
From: Frits van Bommel <fvbommel@wxs.nl>
Date: Tue, 17 Feb 2009 00:08:20 +0100
Subject: [PATCH] Fix the problems exposed by the callingconv1.d test case.

The first was that unless otherwise specified, inputs are assumed to be in
registers even if they specify a "matching output" that's in memory.

While testing that fix, I also ran into a bug causing the generated "matching
output" for any input was always the first one instead of the correct one.
---
 gen/asmstmt.cpp | 21 ++++++++++++++-------
 gen/irstate.h   |  5 ++++-
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/gen/asmstmt.cpp b/gen/asmstmt.cpp
index aa1adc36..58814360 100644
--- a/gen/asmstmt.cpp
+++ b/gen/asmstmt.cpp
@@ -385,18 +385,25 @@ assert(0);
     for(it i = output_constraints.begin(), e = output_constraints.end(); i != e; ++i, ++n) {
         // rewrite update constraint to in and out constraints
         if((*i)[0] == '+') {
-            (*i)[0] = '=';
-            std::string input_constraint;
-            std::stringstream ss;
-            ss << n;
-            ss >> input_constraint;
-            //FIXME: I think multiple inout constraints will mess up the order!
-            input_constraints.push_front(input_constraint);
+            assert(*i == mrw_cns && "What else are we updating except memory?");
+            /* LLVM doesn't support updating operands, so split into an input
+             * and an output operand.
+             */
+            
+            // Change update operand to pure output operand.
+            *i = mw_cns;
+            
+            // Add input operand with same value, with original as "matching output".
+            std::ostringstream ss;
+            ss << m_cns << (n + asmblock->outputcount);
+            input_constraints.push_front(ss.str());
             input_values.push_front(output_values[n]);
         }
         llvmOutConstraints += *i;
         llvmOutConstraints += ",";
     }
+    asmblock->outputcount += n;
+
     for(it i = input_constraints.begin(), e = input_constraints.end(); i != e; ++i) {
         llvmInConstraints += *i;
         llvmInConstraints += ",";
diff --git a/gen/irstate.h b/gen/irstate.h
index 22aa60a1..477b0d1d 100644
--- a/gen/irstate.h
+++ b/gen/irstate.h
@@ -81,6 +81,7 @@ struct IRAsmBlock
 {
     std::deque<IRAsmStmt*> s;
     std::set<std::string> clobs;
+    size_t outputcount;
 
     // stores the labels within the asm block
     std::vector<Identifier*> internalLabels;
@@ -92,7 +93,9 @@ struct IRAsmBlock
     LLValue* (*retfixup)(IRBuilderHelper b, LLValue* orig); // Modifies retval
 
     IRAsmBlock(AsmBlockStatement* b)
-        : asmBlock(b), retty(NULL), retn(0), retemu(false), retfixup(NULL) {}
+        : asmBlock(b), retty(NULL), retn(0), retemu(false), retfixup(NULL),
+          outputcount(0)
+    {}
 };
 
 // llvm::CallInst and llvm::InvokeInst don't share a common base