[Mesa-dev] [PATCH 6/7] i915: Fail without crashing if a Mesa IR program uses too many registers

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

So far this can only happen in GLSL shaders that contain flow-control
that could not be lowered.  These programs would have failed to run on
hardware anyway.
---
 src/mesa/drivers/dri/i915/i915_fragprog.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i915/i915_fragprog.c b/src/mesa/drivers/dri/i915/i915_fragprog.c
index 6e1d709..32050ce 100644
--- a/src/mesa/drivers/dri/i915/i915_fragprog.c
+++ b/src/mesa/drivers/dri/i915/i915_fragprog.c
@@ -303,7 +303,7 @@ do {									\
 /* 
  * TODO: consider moving this into core 
  */
-static void calc_live_regs( struct i915_fragment_program *p )
+static bool calc_live_regs( struct i915_fragment_program *p )
 {
     const struct gl_fragment_program *program = &p->FragProg;
     GLuint regsUsed = 0xffff0000;
@@ -317,6 +317,9 @@ static void calc_live_regs( struct i915_fragment_program *p )
 
         /* Register is written to: unmark as live for this and preceeding ops */ 
         if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+	    if (inst->DstReg.Index > 16)
+	       return false;
+
             live_components[inst->DstReg.Index] &= ~inst->DstReg.WriteMask;
             if (live_components[inst->DstReg.Index] == 0)
                 regsUsed &= ~(1 << inst->DstReg.Index);
@@ -327,6 +330,9 @@ static void calc_live_regs( struct i915_fragment_program *p )
             if (inst->SrcReg[a].File == PROGRAM_TEMPORARY) {
                 unsigned c;
 
+		if (inst->SrcReg[a].Index > 16)
+		   return false;
+
                 regsUsed |= 1 << inst->SrcReg[a].Index;
 
                 for (c = 0; c < 4; c++) {
@@ -340,6 +346,8 @@ static void calc_live_regs( struct i915_fragment_program *p )
 
         p->usedRegs[i] = regsUsed;
     }
+
+    return true;
 }
 
 static GLuint get_live_regs( struct i915_fragment_program *p, 
@@ -394,7 +402,10 @@ upload_program(struct i915_fragment_program *p)
 
    /* Not always needed:
     */
-   calc_live_regs(p);
+   if (!calc_live_regs(p)) {
+      i915_program_error(p, "Could not allocate registers");
+      return;
+   }
 
    while (1) {
       GLuint src0, src1, src2, flags;
-- 
1.7.4.4